Subaru tidbit of the day

[PhyrraM]

I have noticed a fair amount of interest in the 818 from possible FFR repeat customers. Folks who might be more knowledgeable on V8 American iron. While all the tech specs on these Subarus are easy to Google and find out, sometimes it's the little everyday stuff that makes just as much impact.

Motors, gearboxes and eventually brakes are going to have multiple threads dedicated to them. These things prolly won't.

Also, not knowing exactly what FFR is going to re-use and what is going to be in the kit, I'd figure we can use this thread to throw out those seemingly non-important factoids and details.

Tidbit #1:

'02-'03 WRX seats are very good, generally considered the most supportive of any Subaru factory seat. They however look like regular Ma-and-Pop Camry seats, with a squared off top and separate headrests.

'04-'07 WRX and STI seats look very sporty with tall, tapering seatbacks and integrated headrests. They would likely fit the style of the 818 very well and pretty much look like an aftermarket sports seat. They, however, are generally regarded as less supportive than the '02-'03 WRX seats.

[riptide motorsport]

good thread........Steven

[Horhay]

The STi seats are incredibly springy. They are my least favorite part of driving my STi.

[Sergio]

I don't think FFR is going to recommend to use the stock seats for the 818, saving weight would mean the stock seats would have to go.
lighter seats are available and also FFR has the connections (SubeSports) to make (or rename) a whole new seat for the 818.

[crackedcornish]

it will be interesting to see if FFR hits both the 1800lb and $9900 mark

if they use a lot of stock Subie parts I'd imagine weight will become an issue, if they use a lot of aftermarket/specialty parts then the price point may be in danger....we'll just have to wait and see what happens

[PhyrraM]

Tidbit #2

The Subaru front knuckle/hub is virtually universal. The only real exceptions are the rare SVX and the '05+ STI. Both of which are 5x114.5 vs. the 5x100 of every other Subaru.

This means that the same front spindle/hub assembly can accept tiny single piston 1.8 liter base Impreza brakes all the way up to 4 piston '04 (only) STI 13" Brembos. A sweet spot is the stock WRX 2 or 4 piston calipers.

The idea here is that if FFR uses the front assembly in the back, the smaller Impreza brakes can be swapped with zero issues. If FFR keeps them in front, the larger WRX and Brembo assemblies are appropriate. And if it uses custom hubs/knuckles? Well, then the info is still a tidbit.

[PhyrraM]

Tidbit #3

In the American market:

'02-'05 WRXs are 2.0 liters and use a traditional throttle cable.

All other turbos, including '06+ WRX, ALL STIs, Turbo Bajas, '05-'09 Legacy GTs, Forester XTs, and Outback XTs are 2.5 liters and have an electronic throttle.

Non-turbos phased in the electronic drive-by-wire at a slower pace.

[Cooluser23]

I prefer Mitsubishi Evolution, or Dodge Viper seats over any Sti seats I sat in. (I worked as a valet. I drove A LOT of cars)

However I do like the idea of making the seats single donor to keep costs down.

As long as there is enough room to put Cobra Misano, Sparco Milano, or Recaro Sportster CS, Bride, etc. seats in for people who want to spring for extra dough, I'm happy. :)

[PhyrraM]

Tidbit 4

All the 5 speed transmissions bolted behind EJ motors are the same basic design. As they got newer they got upgrades. However, turbo models used a different clutch arraingement than non-turbo models.

All non-turbo models had a traditional push clutch. Early years had a cable mechanism, starting about '96ish hydraulic actuation was phased in depending on engine size.

Turbo models up to about '05 had a pull type clutch. All were hydraulic. All clutch parts, including flywheel are different. Bellhousing accomodations for the throw-out bearing make the trannys physically different, even if interenally similiar.

Starting about '05ish, the turbo 5-speeds started appearing with push clutches too.

The 6 speed on the STI is also a pull type of clutch, but again, all clutch parts are unique from other models.

[GTLee77]

Great info!! Keep it up...

[PhyrraM]

Tidbit #5

All of the Subarus that would make a good donor have headlights and parking lights that automatically go off with the ignition. While this is likely intended to protect the battery, the main switch can be left in the 'on' position for a basic autolamp feature. If you need parking lights while the ignition is off, there is a dedicated switch on top of the steering column.

The first time you accidentally flip it while cleaning the interior, it will take you 30 minutes (and a phone call to a 'Subaru friend') to figure out why your parking lights won't turn off, even though you turned the headlight switch off.

[MDRex]

The switch mentioned above is right on the top of the steering colum. That switch controls the corner marker lights/parking lights, not the headlights, just wanted to make sure people understood which lights PhyrraM is talking about. The marker lights will only stay on when the car is off if that switch is "On". The headlights will never stay on when the car is off, so you can leave your headlight switch to 'On' and have the headlights come on automatically when you start the car.

Also, the fog lights on the Impreza will only go on with the headlights on. The fogs turn off automatically when you turn the highbeams on. But there is a simple hack to get the fogs to go on and stay on whenever you'd like, more info can be found on any of the Subaru forums.

[PhyrraM]

Tidbit #6

The WRX and most other Subarus of the same era have a 16.5:1 steering rack ratio. The STI and '06-'07 WRX have a 15:1 rack.

The '91-'94 Subaru Legacy is unique with a 16.0:1.

[thebeerbaron]

Can you express the rack ratio in turns from lock to lock? I did some quick googling, but didn't come up with much. I know the 15:1 rack will be faster, but I'd like to know what that means in terms of steering wheel travel.

I'm guessing we'll have to de-power the rack for this car. Do you know of any guides to doing that? I know it can be as simple as just looping the lines, but there are better ways where you remove seals and weld up certain bits, depending on the car involved.

Great thread!

[PhyrraM]

Can you express the rack ratio in turns from lock to lock? I did some quick googling, but didn't come up with much. I know the 15:1 rack will be faster, but I'd like to know what that means in terms of steering wheel travel.

I'm guessing we'll have to de-power the rack for this car. Do you know of any guides to doing that? I know it can be as simple as just looping the lines, but there are better ways where you remove seals and weld up certain bits, depending on the car involved.

Great thread!

Without knowing what front knuckles FFR is planning on using, there can be no correlation between gear ratio and turns lock-to-lock. A lower ratio will be faster. Also, the length of the arm on the knuckles will effect how 'fast' the steering is.

I have never depowered a rack, but I'm sure that FFR will provide proper instuctions.

[thebeerbaron]

Without knowing what front knuckles FFR is planning on using, there can be no correlation between gear ratio and turns lock-to-lock.

I thought about that, but isn't lock-to-lock just a function of reaching the physical stops at the end of the rack? Even if you pull the rack off the car, you'd know how many input turns it takes to go from one end of the rack to the other.

The knuckle and arm length would affect steering angle per input degree, and thus a bunch of suspension geometries my pea-sized brain can't handle today, but unless the tires hit the chassis first, it will be the rack that stops the steering travel.

[PhyrraM]

Tidbit #7

Subarus use a 53mm offset wheel. Many aftermarket wheels used on Subarus are 45mm offset.

Folks start to talk about wheelbearings going bad with less than 45mm offset, but it is still debated.

[riptide motorsport]

great thread, i can feel my mind exspanding everyday!!!!!!!!!!!!!!!!!!!!!!!!

[MDRex]

The whole wheel bearing thing is very much up for debate. There are guys that complain theirs went bad fast and then those that race their cars a lot and never have an issue with the wheel bearings. So take any talk of wheel bearing issues with a grain of salt, just like the supposed glass tranny.

[crobin4]

The whole wheel bearing thing is very much up for debate. There are guys that complain theirs went bad fast and then those that race their cars a lot and never have an issue with the wheel bearings. So take any talk of wheel bearing issues with a grain of salt, just like the supposed glass tranny.
I agree I've run a very long time with 35mm offset, and had no issues.

[PhyrraM]

.....take any talk of wheel bearing issues with a grain of salt.....

Completely agree, that's why I made it point to mention it is still debated.

Considering the weight goal of the 818, I wouldn't worry about wheel bearings unless the go-cart/first builds have problems.

[Evan78]

Regarding STi Brembos, I just want to point out that the 05 STi went to a 5x114.5 bolt pattern as PhyrraM mentioned, so the rotors changed to match, but the calipers are all the same as far as I know.

[PhyrraM]

Tidbit #8

The '02 and '03 WRXs had the speedometer centered in the middle of the cluster as the largest gauge. The tachometer was smaller and to the right. There were no USA STIs for these two years.

In '04 they got switched and put the tach as largest and in the middle, where it belongs. The speedo took up residence in the smaller spot to the right. This applied to WRXs and STIs, however STIs have a more 'stylish' electroluminescent cluster.

All speedometers are electronic. There are no speedo cables on the '02+ cars.


IMHO, I prefer the simpler, less distracting, WRX cluster.

[PhyrraM]

Tidbit #9

All modern EJ series turbo Subarus had DOHC heads. The only EJ series motor that had a turbo and SOHC heads was the USA market '91-'94 Legacy turbo.

2.0 turbos ('02-'05 WRX) were traditional DOHC with no variable valve timing.

2.5 turbos (Baja, Forester, Legacy, WRX '06-'07, and STI '04-'07) had variable valve timing on the intake.

'08+ STIs have variable valve timing on both intake and exhaust. Of course, the '08+ are outside the stated donor years and are not expected to be preferred donors.

[riptide motorsport]

how much diference can you exspect performancewise from the dohc verses the sohc? ....thanks Steven

[PhyrraM]

how much diference can you exspect performancewise from the dohc verses the sohc? ....thanks Steven

For the turbo, the SOHC is much older ('90-'94) and only rated at 160HP. It is however a 2.2 vs. a 2.0 in the WRXs ('02-'05). It is pre-OBDII electronics, pro or con? This SOHC is generally considered an inferior head design to newer ones.

For the non-turbos, the SOHC is considered better than the non-turbo DOHC used in mid-late 90s cars. Subaru has only recently ('10 models) switched back to DOHC for non turbo cars.


Subaru guys used to take the DOHC heads and swap them to the 2.2 block, however the advent of the factory 2.5 turbos has curtailed that.

[PhyrraM]

Tidbit #10
For cars Imprezas '93-'07, Legacies and Outbacks '90-'04, Foresters '97-'08, and all Bajas:

Turbo and non-turbo Subarus use different front crossmembers. The turbo crossmember has a notch to clear the exhaust pipe that routes gasses up to the turbo. Because of this slight shape change, the front anti-roll bar is also different between turbos and non-turbos.

Imprezas '08+, Legacies and Outbacks '05+, and Foresters '09+ no longer use the 'coporate' front crossmembers of earlier cars.

[Gollum]

The wheel bearing issue is definitely some muddy water to tread. From all that I've heard from quality subaru techs, the main consensus is that people are either using poor quality "direct replacement" off brand bearings, or they were changed at some point and weren't installed correctly, as the subaru wheel bearings aren't the simplest in the world to change.

On the other side, I've talked to people that have had wheel bearing issues, who seem to really know what they're talking about and say that once they switched to the larger 5x114 hubs the problem went away. One guy I'd talked to had gone through three sets of wheel bearings, all different brands. I can only assume he doesn't know how to install them very well, or there is indeed something else causing bearing failures.


This is all good info. Keep it coming.

[Brian Apple]

Also, wheel bearings are pressed in at a shop unless you use the 05-07 STI hub/carrier which bolt in the bearings and can be done by anyone. STI bearings are larger in diameter and the hub has to be the 5x114. Not interchangeable with the 5x100. This requires the STI axles as the number of splines are different. At the trans though, it requires the STI 6 speed also as the axles on the STI are female input and the WRX are male input to the trans.

[riptide motorsport]

wheres the tidbit??????

[PhyrraM]

wheres the tidbit??????

Travelling and work. Haven't had time to sit down and compose a good one. So, how about a quicky....

Tidbit #11

In addition to a slightly larger intercooler, STIs have a factory intercooler spray setup. It is a trunk mounted tank, nozzles and a dash mounted switch.

WRXs make do with just the hood scoop.

[PhyrraM]

And on a related note:

Tidbit #12

'02-'05 WRXs have a all aluminum intercooler. (2.0 liter)

'06-'07 WRXs switched to an intercooler with plastic endtanks. (2.5 liter)

All STIs had a slightly largr than WRX all aluminum intercooler.

'04+ Turbo Bajas and Foresters had a plastic endtank intercooler very similiar to the '06-'07 WRX.

'91-'94 Turbo Legacies did not have an intercooler.

Later cars ('05+ Legacy/Outback, '08+ WRX, '09+ Forester) use a slightly revised turbo/intercooler/throttlebody routing - making intercoolers non-interchangeable with earlier models. These models had the intercooler bolted to the turbo directly instead of a traditional hose. They also had a plastic intake manifold instead of the aluminum on earlier models. The later motors can be backdated to the earlier design with an intake manifold swap, if desired.

[crobin4]

'91-'94 legacys had a water to air intercooler

[PhyrraM]

'91-'94 legacys had a water to air intercooler

True. Overseas '89-'93 2.0 liter Legacy/Liberty models had an air-to-water intercooler.

North American Legacy 2.2 liter SOHC models had no intercooler.



For completeness:

Overseas '94-'03 turbo models were 2.0 liter twin turbos with normal air-to-air intercoolers

[Justen]

Twin turbos on a 2.0? 2 turbos or 1 twin scroll?

[PhyrraM]

Twin turbos on a 2.0? 2 turbos or 1 twin scroll?

Two sequential turbos. One small and one larger one. They made good power and had good low end, but Subaru struggled with the transition from primary to secondary. Subaru folks have called this the "Valley of Death" for years.

These motors are relatively cheap as imports here in the states because they don't fit left hand drive cars. The traditional Subaru single turbo system bolts up to the longblocks, so complete motors only have longblock value. The factory ECU wiring is fairrly complex, but doable. Of course a standalone will also work.

[PhyrraM]

Tidbit #13

Over the years, Subaru EJ series 4 cylinders have had many versions of heads and blocks. They however are generally catagorized into two groups, Phase 1 and Phase 2. The crossover year is about '98-'99 depending on model.

The main reason for the change seems to be to improve the 2.5 liter motors- which were "short-cutted" from the original 1.6-2.2 liter sizes. There were numerous upgrades, but the one that effects an engine build the most is the relocation of the thrust bearing from the center of the motor (#3 journal) to the flywheel end (#5 journal). There is also double the number of engine-to-transmission mounting bolts on the phase 2 (from 4 to 8), however early cars don't seem to have a problem in this regard.

Another of the improvements applies only to the 2.5 liter motors. Phase 1 had 48mm rod journals. This is smaller than the 52mm standard on all other EJ motors. The assumption is that Subaru used the smaller journal to cram the larger 79mm stroke into the early case. That was rectified on phase 2 when the journals on the 2.5 liter were now back to 52mm like all the rest.

[BrandonDrums]

Tidbit #14

PhyrraM is my current favorite FFR forum member. Awesome stuff man.

[PhyrraM]

Thanks. I intended for others to start throwing out their Tidbits(tm) too.

Tidbit #15

All EJ based Subarus have the engine ECU under the front passenger floorboard on a fairly long harness leg. This should allow a good amount of flexibility on mounting location and access when/if the harness is converted to 818 duty.

The exception is the '90-'94 Legacy which has the ECU stuffed under the dash on the drivers side and has almost no play in the harness.

[PhyrraM]

Tidbit #16

Subaru transmissions have the speedo output up front near the FWD output. Early Legacies used a cable, while all other later cars used a speed sensor. All transmissions will accept either.

Exception:

'05+ Legacies/Outbacks, '08+ Imprezas, '09+ Foresters use the wheel speed sensors for speed reference. These transmissions do not have a spot for the speed sensor/cable at all.

[BrandonDrums]

Thanks. I intended for others to start throwing out their Tidbits(tm) too.



Lol, your tidbits are about 10 miles out from what I can provide. I know a good amount about Subaru's...but not like you good sir.

Are you looking this stuff up or is it all in the noggin?

[PhyrraM]

All from memory, but my knowledge is mostly stock. I admire those folks who can rattle off turos sizes and injectors, custom pistons, and PPG gearsets.

I spent alot of time upgrading my early Legacy with late model parts, to good effect. most of my tidbits come from that endeavor.

[crobin4]

Lol, your tidbits are about 10 miles out from what I can provide. I know a good amount about Subaru's...but not like you good sir.

Are you looking this stuff up or is it all in the noggin?

+1 I've forgotten too much. I retained what I needed to know for my projects, ad evidently purged the rest.
It's what you guys have to look forward to when you get older too.

Remember, Party with moderation.

[Gollum]

I personally love this thread because I'm still relatively new to the subie world, and haven't even owned one myself yet.

Hopefully I can be more help in some other areas.

Keep the info coming!

[bbjones121]

Tidbit of a Tidbit:

Plastic endtanks on the 06+ WRX, 05+LGT/OBT blow pretty easily with stage 2 upgrades. There are options available that are much larger and all aluminum.


And on a related note:

Tidbit #12

'02-'05 WRXs have a all aluminum intercooler. (2.0 liter)

'06-'07 WRXs switched to an intercooler with plastic endtanks. (2.5 liter)

All STIs had a slightly largr than WRX all aluminum intercooler.

'04+ Turbo Bajas and Foresters had a plastic endtank intercooler very similiar to the '06-'07 WRX.

'91-'94 Turbo Legacies did not have an intercooler.

Later cars ('05+ Legacy/Outback, '08+ WRX, '09+ Forester) use a slightly revised turbo/intercooler/throttlebody routing - making intercoolers non-interchangeable with earlier models. These models had the intercooler bolted to the turbo directly instead of a traditional hose. They also had a plastic intake manifold instead of the aluminum on earlier models. The later motors can be backdated to the earlier design with an intake manifold swap, if desired.

[bbjones121]

Tidbit #17

Fuel Systems:

02+WRX, 07+STI, 07+LGT use a top feed fuel injector
04-06 STI and 05-06 LGT use a side feed fuel injector

OEM 02-05 WRX has 420cc
OEM 06-08 WRX has 560cc
OEM 04-06 STI has 535cc
OEM 07-08 STI has 560cc
OEM 05-06 LGT has 535cc
OEM 07+ LGT has 560cc (I think these are good for around 250whp @ sea level)
Pink JDM STI OEM injectors are around 550cc

02-05 WRX fuel pump is 130lph
06-07 WRX fuel pump is 145lph
08+ WRX fuel pump is 155lph
04-07 STI fuel pump is 145lph
08+ STI fuel pump is 175lph
05-07 LGT fuel pump is 145lph
08+ LGT fuel pump is 175lph (Just off the top of my head, I think this was good for around 275-300whp @ sea level)

Since I am a strong proponent of E-85 I will throw this in here:
If you want to run E-85, you should upgrade your system with 15% larger fuel injectors and fuel pump than what you would have with premium fuel.

[PhyrraM]

Tidbit #18

As factory mounted in a Subaru (most '90-'07), 5-speeds and 6-speeds use different shift linkages. Even though they look the same.

Also, 5-speeds have early and late variations of the linkage. You can switch beween the two on any 5-speed however. You just need to use the proper/matching bracket on the shift rod coming out of the transmission.

[mn_vette]

Thanks. I intended for others to start throwing out their Tidbits(tm) too.

Tidbit #15

All EJ based Subarus have the engine ECU under the front passenger floorboard on a fairly long harness leg. This should allow a good amount of flexibility on mounting location and access when/if the harness is converted to 818 duty.

The exception is the '90-'94 Legacy which has the ECU stuffed under the dash on the drivers side and has almost no play in the harness.

This would lead me to believe that the ECU may not be designed to be mounted in the engine compartment like most cars. We may have to put this in the passanger compartment somewhere, especially in warm climates.

[PhyrraM]

This would lead me to believe that the ECU may not be designed to be mounted in the engine compartment like most cars. We may have to put this in the passanger compartment somewhere, especially in warm climates.

While I cannot comment on what temperature thay can tolerate, I can say that you do not want to place it anywhere that might see moisture or dust/dirt. It is NOT sealed.

[bbjones121]

yes definitely not sealed

[bbjones121]

Tidbit #19

Off the top of my head, this is what I remember about lights. If you want OEM HID lights for the 02-03 WRX style, you will have to import them from Japan. They will probably be very expensive, but you could probably find them new. Above that, they will have a cutoff that is on the opposite side of the road (blinding oncoming traffic). You will have to open them up (bake them in your oven) and flip the shield that sits in front of the bulb housing. I had a good pictoral guide to this on the legacy forums, but there are many more WRX owners that probably have tutorials specific to the WRX/Impreza.

For all the 04+ WRX, you can purchase 04+ OEM STI HID headlights.

If you do get the STI HID's, make sure that they come with the leveling motor attached or it might be an expensive upgrade later if you want the ability to adjust the height of the beam from inside the car. Also try to get the motor connector, wiring harness, interior level switch, and connector for interior level switch. You will be able to find wiring schematics for hooking these up on most Subaru forums. I think that the connector is probably the same as the one I used on my JDM HID Legacy headlights, which was Toyota part numbers # 90980-11016 (should be about $6 online a piece and you need two, one for each light) and the wires are Toyota part #82998-12440 (you will need 6 of these and they are overpriced at about $4.50 online a piece). Of course I am sure there are Subaru part numbers for the STI headlights as well, but I don't know those.

There are many retrofit applications with the WRX headlights with better projectors than those that come stock on the STI, but I think the OEM STI lights are the easiest solution to getting HID's and plus they have leveling ability. I am sure you can find somewhere inside the car to mount the leveling switch.

[bbjones121]

Tidbit #19 addition

If you want to save money on upgrades, you will probably find any part you are looking for "used" at a fraction the cost. There are many "parting out" threads that have wrecked vehicles or people are taking off all their aftermarket stuff to sell and put their car back to stock. You will also be able to sell any left over parts from your doner on any of these sites as well. Just scope out the market places on subaru forums: iwsti.com, nasioc.com, subaruoutback.org, subaruforester.org, clubwrx.net, wrxtuners.com, legacygt.com. I am sure I forgot some, but those are the main ones I think.

[PhyrraM]

Tidbit #20
Most of the Subarus suitable for donors came with 16" or 17" in wheels. The '02-'05 WRX came 16x6.5" in a split 5-spoke design. The '06-'07 WRX upped the wheel size to 17x7" to clear the 4 piston fixed calipers that were standard on those years.

Curiously, the earlier '98-'01 Impreza 2.5RS came with 16x7" wheels that clear the 4 piston calipers, even though those cars had smaller-than-WRX brakes.

Most 16" Subaru wheels will clear the '02-'05 2-piston WRX brakes. Only very select OEM wheels will clear the '06-'07 4 piston calipers.

US market STIs had 17x7.5" for '04. For '05-'07 STIs they were 17x8" and a larger bolt circle for the lugs. All STIs in North America had Brembo brakes and require very selective rims to clear.

[readymix]

OH man, I can contribute heavily to this thread. If there is a single stock anything in my car, it's likely interior or body panels. Everything else has been stripped, ripped, swapped or overhauled entirely with new bits.

Subarus are like legos for the most part. Especially from around 1994 through 2007 across the Forester, Legacy and Impreza lines. PhyrraM has touched on most of the differences so far, though. Nice work, buddy.

Some comments. The people saying to take the wheel bearing issue with a grain of salt...spot on. I've run +40 and +42 offset wheels on my car for a number of years with no issue. It's hit or miss, but not a for-certain sort of thing. If you have a press, and you are disassembling things for your FF818 build anyway, might as well replace them, especially if your mileage is high. But odds are, you'll be fine with whatever is pressed in there if it isn't grinding already.

The Subaru driveline across all vehicles lends itself very nicely to an MR layout. Unlike the FWD inline 4's, the transmission mounts to the engine the way a typical FR setup is assembled. The engine sits low due to the pistons moving side to side, keeping the weight low. The transmission is your typical FR type rear shaft design, the difference here is a center differential was added to the back of the unit to transfer power to the front differential which drives the front wheels. Subaru hobbyists have welded the center differential and removed the front shafts creating an FR layout in the past. And removing the center differential and block it off while maintaining the front differential allows for an MR configuration. If you are looking for a very versatile setup for any kit or custom built vehicle, the Subaru EJ series motors lend themselves nicely to any configuration.

For the EJ2X turbo engines, there is a great deal of interchangeability. The EJ20 WRX heads from 02-07 will mount up nicely to an EJ257 STi shortblock, though care has to be taken to use a proper headgasket for compression ratio sake. Pretty much any turbo that works on an EJ257 will work on an EJ20 and vice versa.
The EJ257 differs in overall strength from the EJ205 of the US based WRX. The EJ257 and EJ207 (JDM 2 liter) have a semi closed deck with cylinder reenforcements in the block castings. While the EJ205 is a fully open deck. Strangely, the EJ22 from the 1991-1994 turbo Legacy (Legacy SS) has a fully closed deck with a few coolant passages built into the casting. And EJ20X heads mount up nicely to it...with one big warning. The EJ22"T" from the Legacy SS is an oddity in that the pistons at TDC will actually protrude from the block by a few hundreths of an inch. Which doesn't sound like much, but without proper headgasket thickness, will actually make contact with the heads and cause issues. This can be remedied by using a headgasket that is a bit thicker. It lowers your overall compression ratio a bit, but it will keep you safe. Another great thing about the EJ205 and EJ22"T" is that the connecting rods are the same specs.

I could really go on all day. I have experience with alot of different engine setups. I do all my own work. My car went from the stock 2.0L WRX motor, to a 2.2"T"+WRX head hybrid, to an EJ257+wrx heads hybrid. I've had a number of turbos. And a slew of different fuel/ECU/intercooler setups. Seriously, if you have questions about anything related to the engine, feel free to shoot a PM.

[bbjones121]

Now we are getting more Subaru guys over here. I will be posting updates to the designs in some of the Subaru forums to get some more interest.

[readymix]

Now we are getting more Subaru guys over here. I will be posting updates to the designs in some of the Subaru forums to get some more interest.

We have a thread going on the local forum (Minnesota). Most Subaru enthusiasts would get behind the idea of this car. But 99% of them daily drive their Subarus and likely aren't down with trashing one to make another car out of it. Luckily, I'm in that 1% that parks his car most of the time, and doesn't have any qualms about destroying it to donor a FF818 car.

[bbjones121]

We have a thread going on the local forum (Minnesota). Most Subaru enthusiasts would get behind the idea of this car. But 99% of them daily drive their Subarus and likely aren't down with trashing one to make another car out of it. Luckily, I'm in that 1% that parks his car most of the time, and doesn't have any qualms about destroying it to donor a FF818 car.

I daily drive my corn fed zilla18g 2006 LGT too. I plan on having both. Wheels are interchanged, I will have stash of oil filters, and hopefully have one engine that I am rebuilding to put in either car.

[readymix]

I daily drive my corn fed zilla18g 2006 LGT too. I plan on having both. Wheels are interchanged, I will have stash of oil filters, and hopefully have one engine that I am rebuilding to put in either car.

I'm just hoping they keep the same wheel and tire specs from the Impreza, because Uncle Sam bought me a set of Work VS-XX 3 piece wheels a couple years ago, and I don't want to give them up for this.

[PhyrraM]

Tidbit #21

For Subarus with rear disc brakes, the parking brake is not integrated into the rear calipers. They use the mini-drum brake set up, with a dedicated drum parking brake. The drum and the rear rotors are cast as one piece.

All Subarus but the STI use the same diameter drum regardless of rear rotor size. The STI uses a larger parking brake drum than lesser Subarus.

Of course, it's not yet know if the rear assembly will be used on the 818 at all.

[PhyrraM]

Tidbit #22

As with most modern cars, the Subaru HVAC unit is completely behind the dashboard with the only penetrations through the firewall being 2 water hoses and 2 freon pipes. The fresh air comes from the cowl area on the passenger side.

If attempting factory dash and HVAC in your 818 the HVAC unit and the dash should come from the same car. There are numerous small wiring and hardware changes, depending on year, trim level, and model that need to be accounted for if trying to 'mix-n-match'.

[PhyrraM]

Tidbit #23

The 'New to the USA' '02/'03 WRX had only one factory option for the states, auto or manual transmission. All the other "options" were dealer or port installed and pretty meaningless items. Things such as auto dimming rearvier mirrors, upgraded speakers, a short shifter, a few different shift knobs, and a vary rare 17" BBS wheel option.

Starting in '04, once Subaru realized these things will actually sell well here, factory options and new trim levels appeared.

[2KWIK4U]

You must be an encyclopedia of Subaru :)

I am mainly a Chevy guy but I will have to get some books and start reading up on Subaru if I am going to build an 818 I guess.

[PhyrraM]

Tidbit #24

If the 818 uses the factory WRX dash, the '02-'03 might be more appropriate.

The '04+ WRX/STI integrates the console into the center stack on the dash. It might look out of place without the console.

On the '02-'03 WRX the center stack has a standalone look to it, with the console starting under the dashboard.

[PhyrraM]

Tidbit #25

For the earlier models:

Just because it has a hood scoop, doesn't automatically make it a turbo.

'96-'99 Outbacks and Legacy GTs had hoodscoops and 2.5 liter N/A motors.

'97-'01 Outback Sports had hoodscoops and 2.2 liter N/A motors.

'98-'01 Impreza 2.5RSs had hoodscoops and 2.5 liter N/A motors.

From '02+ you can safely use the hoodscoop = turbo rule.

[mn_vette]

Tidbit #25

For the earlier models:

Just because it has a hood scoop, doesn't automatically make it a turbo.

'96-'99 Outbacks and Legacy GTs had hoodscoops and 2.5 liter N/A motors.

'97-'01 Outback Sports had hoodscoops and 2.2 liter N/A motors.

'98-'01 Impreza 2.5RSs had hoodscoops and 2.5 liter N/A motors.

From '02+ you can safely use the hoodscoop = turbo rule.

That is a great bit of knowledge to have. It may save a few people some rides out to look at donors or someone some big cash if they are buying a wrecked one without inspecting it.

[VF48WRX]

Tidbit:
You can run an RS trans on this kit to get the following ratios:

1st - 3.545
2nd - 2.111
3rd - 1.448
4th - 1.088
5th - 0.780
Final - 4.111

I'm running an RS trans and rear diff in my 02 WRX. Only thing I had to change was the clutch slave & clutch/flywheel due to being push instead of pull style (and rear diff of course)

I think this will make a nice trans for the 818.

[riptide motorsport]

what is a RS trans and how much do they cost? ....Steven

[StatGSR]

^ 2.5RS impreza, depending on the year $100-500ish. Not exactly sure what year RS he is talking about as i bet the pre 02's likely have different ratios, also may be similar to a legacy gt or outback. i posted up the uber subaru transmission ratio list on another thread a couple weeks ago...

http://thefactoryfiveforum.com/showthread.php?1363-My-only-concern-is-Gearing&p=16557&viewfull=1#post16557

[VF48WRX]

what is a RS trans and how much do they cost? ....Steven

I'm running an 01 Impreza RS (non turbo 2.5 liter) trans. They are uber cheap used..

[thebeerbaron]

I'm getting ready to yank the motor out of my donor in order to replace what I hope are just bad headgaskets. I'm sure I'll come up with some more tidbits, but this one may save you some angst:

On at least the 2002 motor (and maybe other years), the front oxygen sensor is accessible through the passenger wheel well. An oxygen sensor socket will not work, as part of the frame is in the way. Due to heat shields on the headers, an open-end wrench or crows-foot wrench will not work. Your best bet (and I did not have this tool handy) is an offset-style tool like this (http://www.amazon.com/Powerbuilt-648691-Oxygen-Sensor-Offset/dp/B00390BS7C/ref=sr_1_8?ie=UTF8&qid=1306699634&sr=8-8).

http://ecx.images-amazon.com/images/I/31eFoDvSNtL._SS500_.jpg
I'm not recommending that particular one, just that style. I'll let you know how it goes when I get the right tool.

[riptide motorsport]

Ah yes. .............a crows foot socket.........

[thebeerbaron]

I think of "crows foot" as having the drive point flat with the plane of the nut. That won't fly on the WRX because the hex on the sensor is recessed inside a heat shield. You need the reach this thing has between the square drive and the hex face to get in there.

[wjfawb0]

I picked up one of the offset O2 sockets for my 05 STI. It was about the only way to get the O2 out when I changed the up-pipe and belt sanded the header flanges.

[Steve91T]

Here's a question...what is the weight difference between a n/a engine and a turbo one? 75 lbs? If someone were to buy an n/a engine and have it rebuilt with higher compression, bigger valves, bigger cam, what would it cost and what kind of power would be expected?

I know it wouldn't be anything close to what the turbo engine could produce, but the simplicity, durability, and lightness of an n/a engine could be a lot of fun.

Steve

[Dave Smith]

Fantastic information.

[Silvertop]

Here's a question...what is the weight difference between a n/a engine and a turbo one? 75 lbs? If someone were to buy an n/a engine and have it rebuilt with higher compression, bigger valves, bigger cam, what would it cost and what kind of power would be expected?

I know it wouldn't be anything close to what the turbo engine could produce, but the simplicity, durability, and lightness of an n/a engine could be a lot of fun.

Steve

I'm no Subie expert, so others on this site can probably do a better job of answering your questions, but I did do a little bit of research on NA powertrains, and I'll share what I learned about what is available out there.

Most year 2000+ NA Subie engines are 2.5 Liter, developing in the range of 170 HP. They are mostly SOHC rather than DOHC, which (to me) is a good thing, since you will only need to buy two cams (one per head) rather than four. With a mild street performance cam set, some air intake and exhaust upgrades, a reasonable ECU reflash (there are some reasonable off-the-shelf ones out there.....), and maybe a lightweight flywheel and crank pulley, one should be able to get close to the stock horsepower (227) of the early 2000's WRX Turbo engines. If you want to swing past the 6500 RPM redline, you'll need heavier valve springs too (and they're kinda spendy). Without the valve springs, you'll likely spend $1500-2000 on engine mod parts. The engine will reportedly take the extra power without need to beef up the internals.

The major benefits of using the NA engine is that you will come away with a much broader torque curve (assuming you don't get too silly with the cam upgrade) and can use a less expensive donor car. However, if your alternative is to run with an unimproved Turbo engine, you'll probably eat up most of the cost saved in using a standard Impreza over a WRX.

Can't address the weight difference, but I'm guessing that it would be less than 75 lbs. Mostly the weight of the turbo and the intercooler.

I'm not sure which way I will jump when the time comes. I probably won't be able to resist tweaking the engine a little, no matter whether I go with a WRX donor or a standard Impreza, so the cost savings may be real. It may have more to do with the aesthetics of driving a car with an NA motor vs a Turbo. The other big deal is the torque range. Mod for mod, though, the Turbo will ultimately be faster. Either way, in a car this light, great fun will be available. Much to think about.

Again, I'm no expert. Subie guys, did I get it right?

[Ks2]

even with 200 horsepower in a car of this weight you will be plenty fast, many of the other subarus i see in the SCCA races are N/A with light motor modifications and are still very competitive

if i remember correctly some standard engine modifications most of them utilize with stock internals, upgraded injectors and fuel pump, lightened components (pulleys flywheels etc) larger intake and exhaust headers and a good tune. these guys run around 190-200 depending on the tune and about the same torque, the motors are much more durable and cheap

[thebeerbaron]

OK, so I'm not exactly sure why, but that particular tool did NOT get the job done. It fit over the wires and got down into the little recess in the heat shield, but I couldn't get any purchase on the sensor, the socket just kept spinning. I think it might be too wide to fit down into the recess, but I can't say for sure. Curses.

Going to go check with the Scooby forums and figure out what I'm missing...

[wjfawb0]

Seems like I might have used a crescent wrench to get a grip on the oxygen sensor to break it free before I had the tool. I suspect the previous owner "clearanced" the heat shield for me.

[willy]

If subaru has somuch interchangeable stuff how about the lower controlarms , and other things need for teh 818. This would give us a much wider donor base to choose from than just a WRX.

[Scubynubie]

OK, so I'm not exactly sure why, but that particular tool did NOT get the job done. It fit over the wires and got down into the little recess in the heat shield, but I couldn't get any purchase on the sensor, the socket just kept spinning. I think it might be too wide to fit down into the recess, but I can't say for sure. Curses.

Going to go check with the Scooby forums and figure out what I'm missing...

It has been a long time, but if I remember correctly, you can use a Dremmel to cut the heatsheild enough to slid the O2 sensor wire out. Then there is just one, or maybe two bolts on the top side of the shield to get out, and the shield comes off. Once that is out of the way, it is a lot easier to get at the sensor. Also, remember that you can un-plug the sensor up in the engine bay too.

Up-Pipe = Fun

[thebeerbaron]

Really, just one or two to get that heat shield off? I was looking at twice that. I must be doing things the hard way again. NASIOC has me convinced I can get the motor out without removing the sensor, if I'm careful. We'll see Sunday.

[readymix]

Yeah, you should be able to pull the motor without removing that sensor. Like Scubynubie said, there is a connection to that sensor further up the wire that should allow you to remove the engine with the pigtail hanging. The heat shields can be difficult to remove, those bolts are down low where the water and snow tends to fly around, and they can get corroded into place. I think one of mine had to be cut off.

[Silvertop]

I'm not sure if this is the right thread for this, since it is a question rather than a tidbit, and perhaps slightly off-topic, but I'll run it up the pole anyhow......

I've become aware of an outfit called Proflow Design which specializes in reboring and upgrading throttle bodies for Subaru (among others) for better airflow at a cost of $175-$250, depending on model. Is this a useful and cost effective improvement? Will it benefit performance without making matching upgrades to the fuel injection side of the process? Does anyone have any experience with this?

[kyle242gt]

Generally, TB upgrades are more helpful on NA applications. I wouldn't bother.

[prematureapex]

Tidbit #20
Most of the Subarus suitable for donors came with 16" or 17" in wheels. The '02-'05 WRX came 16x6.5" in a split 5-spoke design. The '06-'07 WRX upped the wheel size to 17x7" to clear the 4 piston fixed calipers that were standard on those years.

Curiously, the earlier '98-'01 Impreza 2.5RS came with 16x7" wheels that clear the 4 piston calipers, even though those cars had smaller-than-WRX brakes.

Most 16" Subaru wheels will clear the '02-'05 2-piston WRX brakes. Only very select OEM wheels will clear the '06-'07 4 piston calipers.

US market STIs had 17x7.5" for '04. For '05-'07 STIs they were 17x8" and a larger bolt circle for the lugs. All STIs in North America had Brembo brakes and require very selective rims to clear.

Good info, a couple additions:

Not sure it's fair to say they went to 17" wheels to clear the brakes.

The 06-07 4-pot brakes aren't any larger in overall diameter than the 02-05 2-pots. They actually require less diameter (being a true caliper, they sit closer to the identically-sized rotor). Where they lacked clearance with the 16x6.5" WRX wheels was due to their width (their front face hit the back face of the spokes).

Thus, diameter wise, they are in fact more suited to smaller wheels. Hence, you can run some 15" wheels on the 4-pots, but not on the older 2-pots.

A 3mm spacer is required to run the 4-pots on 02-05 Impreza 16" wheels due to their width.


Another note about the 4-pots: Contrary to popular belief, they are actually weaker than the older 2-pot squeezers. They offer less clamping force.

However, in addition to easier pad changes, they are stiffer as a result of being true opposable calipers, compared to the sliders. So, you get some added pedal feel, easier pad changes, and a reward bias shift.

That reward bias shift is really what makes the improvement over the 2-pots. Who would have thought, improved braking by lessening braking force. :p

[Silvertop]

Generally, TB upgrades are more helpful on NA applications. I wouldn't bother.

Useful to know. And actually, it is not clear yet whether my donor car will be wrx turbo or NA, so the TB upgrade could turn out to be useful...... Thanks for the input.

[Gollum]

Generally speaking, most people that upgrade to larger throttle bodies end up with a much larger throttle body than needed. They think they're getting more power because they feel more power with less pedal movement. Really all they've done usually is moved their pedal to air movement, not increased ingested air. With an "optimum" throttle body size at peak RPM you should be able to move through about the last 5% or less and feel no power difference. Throwing a large throttle body on like oh so many 240sx kids do ends up with more than 10% of the end of the pedal movement just being "full throttle".

Now, if you want to talk about doing things to make the throttle more aerodynamic that's a whole different topic, and one 60mm throttle body might not perform the same as another 60mm throttle body.

So as with everything else engine related, it all comes down to having a well engineered SYSTEM, not just a part.

[Flamshackle]

Generally, TB upgrades are more helpful on NA applications. I wouldn't bother.

Unless you have a 500HP+ monster then this is totally a waste of time. I have been modding and tuning subaru motors all my car enthusiast life.

mod list and order for a subaru turb motor= exhaust mod/intake mod/intercooler upgrade/retune... This is the best bang for your buck at a bolt on level and one MOST enthusiasts have the time/money for without compromising reliability of the engine internals.

from there things get costly and you really need an STI block/stronger internals to RELIABLY take it further.

check out these guys...
http://www.mrtperformance.com.au/performance

They are the BEST subaru tuners I know of. Although for me they are just across the ditch they have LOADS of experience and results to back it up for our engine of choice here for the 818.

I was in Sydney last week talking to Bret Middleton (He runs MRT) and suggested he get in touch with Dave Smith to offer different packages to the 818 customers. This would be a match made in heaven for power upgrades on the mighty EJ20.

Dave Smith you really should get in touch with this bloke. He really knows about subaru tuning and would be a good "world" engine package option.

[Twinspool]

Since the engines destined for 818s will be out and on a stand anyway, what are the opportunities for reliability that could be readily exploited?

For example, is that #4 cylinder weakness (?) a thermal issue, oiling problem, fuel distribution?

[ZeroDrift]

Some useful information about engines:
-2005 Legacy 2.5NA intake manifolds flow exceptionally well. I've heard that they rival Cosworth's intake manifold, and cost a fraction.
-2005 Legacy GT transmissions have taller gear ratios compared to other 5mt transmissions. You can also add a gear driven speedometer fairly easily.
-Subaru's SOHC heads flow exceptionally well, and will yield great low end torque on turbo engines. If I recall correctly, max flow is in the 250cfm range. They also have a great roller cam setup.
-2005 Legacy 2.5 NA (not 100% sure of the year) will have SOHC heads with an extra lobe on the camshaft. This is very much like Honda's V-Tec
-You cannot install 2.5L heads on a 2L engine, but you can install 2L heads on a 2.5L engine.
-Be weary of cylinder #4 when making more power than stock. Should any piston fail, this one will be the first to go typically.
-STi factory connecting rods can handle a great deal of power and are affordable. I've heard people achieving 450whp reliably with OEM rods.
-STi oil pumps are 11mm, while most WRX's that don't have AVCS will have a 10mm pump. JDM STi's that have dual AVCS (intake & exhaust) will have a 12mm oil pump. Older NA models will have anything from a 7mm oil pump to a 10mm.
-Every time the head is milled flat, camshaft timing will change slightly. There are aftermarket adjustable idler pulleys that can be used in extreme cases. These idlers can also be used when mixing phase 1 and 2 engines and heads.
-2008 STi crankshafts are nitrade coated from the factory.
-STI oil pans differ from other models, but aside from larger capacity, the dip stick tube is also shorter!

Non turbo engines will use a different coolant crossover pipe. You can modify the crossover to fit, but expect to cut and weld on the aluminum piece:
http://img827.imageshack.us/img827/2063/dsc0741o.jpg

Open Deck, Semi Closed Deck, and Closed Deck Blocks:
All non turbo engines are considered to be Open Deck blocks. STi, and newer 2.5L Turbo engines have a Semi Closed Deck, while 2.2L Turbo models and some rare 2.0L engines will have a fully closed deck.

Open Deck:
http://img37.imageshack.us/img37/2927/72809746.jpg

Semi Closed Deck:
http://img442.imageshack.us/img442/6103/dsc0737f.jpg

http://img824.imageshack.us/img824/5206/dsc0738w.jpg

Semi Closed Deck blocks will have additional reinforced webbing on the outside of the block halves.
http://img99.imageshack.us/img99/5564/dsc0739a.jpg

Closed Deck:
http://www.scoob.co.uk/typer/cdb25hr.jpg

Suspension:
-Non turbo Subaru's (and turbo wagons) will have 10mm narrower control arms than a WRX.
-STi models will have aluminum front control arms and improvements have been made to the rear arms as well. These arms are the same length as a WRX.
-STi models have a stiffer rubber used in bushings throughout the chassis.
-2005+ STi models will have the 5x114.3 bolt pattern. This is because they have much larger/stronger wheel bearings.
-2005+ STi steering knuckles are thicker where the McPherson strut mounts. As such they will need machine work to fit older models, and of course new rims.
-2005+ STi models have different axles than WRX and the standard Impreza's.
-WRX, and STi axles are also longer than non turbo models. This is due to the different length control arms.

Misc:
Subaru's boxer rumble is because the exhaust is 'uneven' and as such, the exhaust pulse will overlap causing the rumble. Headers that state they are unequal length will retain the rumble, while equal length headers will loose this 'rumble'.


That is all for now. :)

[Flamshackle]

Since the engines destined for 818s will be out and on a stand anyway, what are the opportunities for reliability that could be readily exploited?
For example, is that #4 cylinder weakness (?) a thermal issue, oiling problem, fuel distribution?

Yea the leaning out of the number 4 is easily fixed with a split fuel rail mod... its no biggy though and a good pump can help solve it also.
oiling problem? iv owned subs for years and they have good oil supply.

1 thing though that's reported in US is the pickups can have fatigue/cracking/catastrophic failure issues. uncommon but regular enough to cause alarm I guess...

the biggest one will be the exhaust route. It will have to be modded anyway to suit the rear so that will reap the most rewards immediately from a stock setup.

at least changing spark plugs will be easier in this car (hopefully)

[Ks2]

some early wrxs in very cold weather (below zero) have fuel line leaks (some fuel will pool on the top of the motor) i had to replace the lines in the WRX motor and then again when i swapped to the JDM STI motor of the same year so if you live somewhere where it gets really flipping cold you might upgrade to silicone lines while the motor is out (it is easy when the motor is still in the subaru, don't know about the accessibility in the 818)

wheel bearings tend to fail on heavily modified applications, i have heard packing them with high temp grease helps, but that is up for debate... i have replaced the front wheel bearings once and the rear twice (well still in the process... have been busy)

while the motor is out, get good motor mounts (group N) they are cheap and well worth the money

[Silvertop]

Now, if you want to talk about doing things to make the throttle more aerodynamic that's a whole different topic, and one 60mm throttle body might not perform the same as another 60mm throttle body.

So as with everything else engine related, it all comes down to having a well engineered SYSTEM, not just a part.

The particular vendor (Proflow Design) that sparked my curiosity and my question specializes in modifying the customer's existing throttle body, probably more for smoother flow than greater flow. The modification involves adding only 2mm to the bore, a more streamlined and tighter fitting butterfly, and apparently some tapering in key flow areas. It doesn't seem to me that adding 2mm of bore is going to dramatically increase the amount of air that can be delivered to the system.

However, based on this response (and others) here, it DOES appear that there are better places for me to spend my money.

[PhyrraM]

...
Suspension:
-Non turbo Subaru's (and turbo wagons) will have 10mm narrower control arms than a WRX.
.....

Correction. Even non-turbo 4 door sedans from '02-'07 have the wider suspension and control arms.

So, from '02-'07 ALL sedans are wide, and ALL wagons are narrow. This only 100% applies to the North American market. In other markets, there were narrow sedans for some years. Look for the fender flares.

[Flamshackle]

wheel bearings tend to fail on heavily modified applications, i have heard packing them with high temp grease helps, but that is up for debate... i have replaced the front wheel bearings once and the rear twice (well still in the process... have been busy)

while the motor is out, get good motor mounts (group N) they are cheap and well worth the money

good call on fuel lines...
We won't have any problems (bar std wear and tear) with our wheel bearings on the 818 however as the loads on them will be dramatically decreased as the car will weigh over 600kg less than the application they were spec'd for.

[Scubynubie]

Another note about the 4-pots: Contrary to popular belief, they are actually weaker than the older 2-pot squeezers. They offer less clamping force.

However, in addition to easier pad changes, they are stiffer as a result of being true opposable calipers, compared to the sliders. So, you get some added pedal feel, easier pad changes, and a reward bias shift.

That reward bias shift is really what makes the improvement over the 2-pots. Who would have thought, improved braking by lessening braking force. :p

This is actually wrong. The 4-Pot calipers do offer better clamping force than the stock WRX calipers. No question.

I swapped to these calipers with the same pad compound (Hawk HPS at the time) and tires, and where I was not able to get into ABS before (sticky tires on the track), with the 4-Pot's I could. As for the brake bias argument, this is also wrong.

I have since switched to the H6-rear rotors (larger diameter) and they dramatically improved the braking performance by evening out brake distribution.

FWIW.

[Scubynubie]

Some useful information about engines:
-2005 Legacy 2.5NA intake manifolds flow exceptionally well. I've heard that they rival Cosworth's intake manifold, and cost a fraction.
-2005 Legacy GT transmissions have taller gear ratios compared to other 5mt transmissions. You can also add a gear driven speedometer fairly easily.

Keep in mind though that the LGT had 4.11 final drive up until 2008 or 2009 ( I don't remember exactly) Because of the weight of the car 818, I'm going to guess that the 3.7 :1 final in the 06 - 07 is going to be ideal

-Subaru's SOHC heads flow exceptionally well, and will yield great low end torque on turbo engines. If I recall correctly, max flow is in the 250cfm range. They also have a great roller cam setup.
-2005 Legacy 2.5 NA (not 100% sure of the year) will have SOHC heads with an extra lobe on the camshaft. This is very much like Honda's V-Tec
-You cannot install 2.5L heads on a 2L engine, but you can install 2L heads on a 2.5L engine.
-Be weary of cylinder #4 when making more power than stock. Should any piston fail, this one will be the first to go typically.
-STi factory connecting rods can handle a great deal of power and are affordable. I've heard people achieving 450whp reliably with OEM rods.
-STi oil pumps are 11mm, while most WRX's that don't have AVCS will have a 10mm pump. JDM STi's that have dual AVCS (intake & exhaust) will have a 12mm oil pump. Older NA models will have anything from a 7mm oil pump to a 10mm.

Sorry but all this is completely wrong. The WRX and STI used a 10mm pump up to 2008 (Yes even the STI with AVCS). The 2008+ STI went to a 11mm pump because it started using AVCS on intake and exhaust cams. The WRX still uses a 10mm pump to this day.

Also, the 12mm JDM pump was never on an STI. Nope, never was. It is actually from the twin turbo Legacy.

-Every time the head is milled flat, camshaft timing will change slightly. There are aftermarket adjustable idler pulleys that can be used in extreme cases. These idlers can also be used when mixing phase 1 and 2 engines and heads.
-2008 STi crankshafts are nitrade coated from the factory.
-STI oil pans differ from other models, but aside from larger capacity, the dip stick tube is also shorter!

All the 2.5 LIter Subaru's use the same oil pan (Okay there are 2 or so variations, but the overall design is the same) You can tell them because they have a cut-away in the pan (which is where the twin scroll JDM headers lived). The 2002 - 2005 WRX use a different oil pan that actually has higher capacity because it does not have the afore mentioned cut-out.



Corrections are in bold.

[ZeroDrift]

Corrections are in bold.

Thank you for some of the corrections. I did make some mistakes with my initial post, but not as much as you correct.

Subaru 4 cylinder oil pans are all compatible, yet are not built the same. I must be more specific in the future. Here is a link with some pictures and an explanations: http://forums.nasioc.com/forums/showpost.php?p=27383408&postcount=36

The oil pump info that I read was possibly not a credible source, so that may very well be.

[prematureapex]

This is actually wrong. The 4-Pot calipers do offer better clamping force than the stock WRX calipers. No question.

I swapped to these calipers with the same pad compound (Hawk HPS at the time) and tires, and where I was not able to get into ABS before (sticky tires on the track), with the 4-Pot's I could. As for the brake bias argument, this is also wrong.

I have since switched to the H6-rear rotors (larger diameter) and they dramatically improved the braking performance by evening out brake distribution.

FWIW.

No, you are certainly mistaken.

8% less brake torque with the 4-pots. That is a fact.

It is COMMON knowledge that the 4-pots have a smaller piston area than the 2 pots. Search on nasioc.

As for the bias, no again, not wrong. With less brake torque up front, your bias is effectively shifter rearward. I too run the H6 rears (and the 4 pots on my last 2 bugeyes), for added rear bias.

A quick search on your part would have yielded about 10000 threads on the topic. Perhaps that would have been a wise thing to do before taking the time to call someone wrong. Again, this is common knowledge.

http://forums.nasioc.com/forums/showpost.php?p=8994574&postcount=2

There is an excel spreadsheet in that link with all the piston area data, as well the the effect on brake bias associated with common brake swaps.

Full thread (from above post):

http://forums.nasioc.com/forums/showthread.php?p=8994574#post8994574


One of COUNTLESS threads discussing the subject:

http://forums.nasioc.com/forums/showthread.php?t=1983223&highlight=4+pots+upgrade

Post 8, for example, provides correct information.



There are several advantages to the 4-pots, but heat capacity and brake torque are most certainly not. The rear bias shift, increased pedal stiffness, and more pad options are the advantages.

[Silvertop]

Does anybody out there know if the aftermarket equal-length header systems available for NA Imprezas typically terminate at the same location in the car as the stock unequal-length ones? Also, do the stock NA and turbo headers terminate at the same location on the car?

The reason I ask -- I'm guessing that the base kit will probably not include headers in the base price (maybe as an extra cost option)-- but will include the exhaust system from that point back, since it will have to be completely different from the original system....

It's a little early, but I'm planning my engine mods for an 818 using an NA Impreza-based donor.

[riptide motorsport]

the kit will most likely include a 'connecting' pipe system and use the stock manifolds and mufflers.......Steven

[305mouse]

Does anybody out there know if the aftermarket equal-length header systems available for NA Imprezas typically terminate at the same location in the car as the stock unequal-length ones? Also, do the stock NA and turbo headers terminate at the same location on the car?

OEM and aftermarket NA headers will end at the same spot. NA and turbo headers are completely different. On a turbo the exhaust manifold goes from drivers side to meet up the passenger side and then merge to the UP pipe, which connects to the turbo, then to a Down pipe. Since NA's don't have turbo's, that whole system is different.

[StatGSR]

its a kit car, i dont see why it would include an exhaust at all...... if its not something you can do, that's what exhaust shops are for...

honestly i would think they are doing alright so long as the car can fit the oem NA and turbo headers without issues

as for NA equal length headers, yes they exist, i know obx makes some, just google/ebay it

[Silvertop]

the kit will most likely include a 'connecting' pipe system and use the stock manifolds and mufflers.......Steven

That is my assumption too -- and is why I asked the question. Per 305Mouse's answer, if the NA manifold or header terminates at a different location than the turbo header, as it apparently does, the connecting piping provided in the kit (which will be meant for the turbo application) will most likely not work for someone using an NA engine. Which may mean an additional expense. The exercise here is an attempt to figure out if starting with an NA donor will wind up being less, the same, or more expensive to complete, independently of the fact that the NA donor car itself may be significantly less expensive to buy. Especially after spending a couple of thousand tweaking the NA engine (Cams, intake mods, equal length headers, ECU tune) to get it in the vicinity of 200HP, which is my idea of what it ought to have.

Of course, it is entirely possible that FFR will offer connective piping for the NA as well as for turbo. Time will tell on that. I'm really getting way ahead of myself.
With luck, the answers will be clear before I find myself faced with the decision to buy a particular donor car..............

[Silvertop]

its a kit car, i dont see why it would include an exhaust at all...... if its not something you can do, that's what exhaust shops are for...

honestly i would think they are doing alright so long as the car can fit the oem NA and turbo headers without issues

as for NA equal length headers, yes they exist, i know obx makes some, just google/ebay it

If their original product is any benchmark, there probably WILL be manifold-back piping included in the kit. But you are right, One can always get something made up.

[StatGSR]

Especially after spending a couple of thousand tweaking the NA engine (Cams, intake mods, equal length headers, ECU tune) to get it in the vicinity of 200HP, which is my idea of what it ought to have.

I think you (like me) need to hope and pray that we can slip an EZ30 into the 818

[305mouse]

The axelback muffler from an 04-07 STI will work on any 02-07 WRX and I know 06-07 NA Impreza's. Most likely 02-05 as well, but my memory fails me right now. I 'm 99% certain it does. Anyways, off the muffler the pipe takes a dogleft to the right and is probably a good 18-24" long. With the length of the muffler and pipe I don't forsee it being used in this application. I think custom or coming with the kit is the way it'll be.

[Silvertop]

I think you (like me) need to hope and pray that we can slip an EZ30 into the 818

Well, there's an interesting thought. What donor car does THAT come in? And how do I resist the urge to tweak THAT engine? Not that it would need it............:)

[Silvertop]

....................I think custom or coming with the kit is the way it'll be.

Yes. And most likely, if one selects something other than a turbo donor, custom will probably be the ONLY answer. That's OK -- but one will want to understand these kinds of things as he makes his donor choice.

[Inthenameofweez]

While using a WRX or STi oil pan, it is IMPERATIVE that the corresponding oil dipstick is also used. Without, the readings will be wrong due to the difference in how the pan holds the oil, not necessarily how much. Without going into deep detail that I may be incorrect about, the STi pans did a better job of keeping the oil IN THE PAN and near the pick up (decreased slosh). There is also an issue that has been mentioned previously in this thread (oil pick up). The pick up will actually fracture at the weld on the flange. This creates a slight air introduction prior to the oil pump. Cavitation (think of trying to put oil in a blender) results in rod bearing and sometimes main bearing failure. This will also destroy the cam journals. Aftermarket baffles, pans, and pumps are a good idea for someone who will be racing the vehicle in any circuit type race.

[rori]

Correction. Even non-turbo 4 door sedans from '02-'07 have the wider suspension and control arms.

So, from '02-'07 ALL sedans are wide, and ALL wagons are narrow. This only 100% applies to the North American market. In other markets, there were narrow sedans for some years. Look for the fender flares.

Do we have any idea how this will effect compatibility with the 818 kit? Will a wagon be a suitable donor?

[thebeerbaron]

From the "do as I say, not as I do" files.

The upper coolant tank on the 2002-? WRX is a two-piece metal unit comprised of a cast bottom and a stamped flat top (it has the radiator cap neck and various coolant connections on it). The stamped metal top plate is held on by a bunch of M6 bolts.

DO NOT SEPARATE THE TWO HALVES

Even if the tank looks crusty and you want to clean it out, clean up the stamped portion, etc. There is a gasket in a channel on the mating surface of the cast piece. It is not available from the dealer. This tank is not a serviceable item, you are expected to throw out the perfectly good (if rusty) old one and buy a new tank for $80-$100 (depending on your source).

You want to know how I figured this out? :)

[riptide motorsport]

Ah yes....the voice of experience!!!!!

[PhyrraM]

Do we have any idea how this will effect compatibility with the 818 kit? Will a wagon be a suitable donor?

Other than stating "....WRX wagons and sedans....." FFR has not addressed if, or how, they will deal with the two Subaru "track widths". Fully adjustable upper control arms *should* do the trick.

[Ironhydroxide]

^ In response.. the WRX Wagon is no longer than the Sedan in drivetrain length, the transmissions and engines are 100% interchangeable, and therefore a wagon will work for donor.

[StatGSR]

^ yea that's never been up for debate, the concerns are with the track width differences between sedan and wagon/other donor models

the length of the car has no bearing anyway since we wont be using a drive shaft from any donor....

[Ironhydroxide]

hmmmm well, true... maybe i'm confused at the problem then.

I just took a "wagon" subframe and suspension and bolted it up to a "sedan" and the track was all the same (was doing a FWD to AWD swap)

but, it would seem that in the prototype pics. the knuckles aren't used, and the only thing used from the engine out, is the Axles... and if I'm not mistaken Impreza Axles are the same, no matter if it is the Impreza Outback Sport, or the Impreza Sedan. (now Legacy is different, slightly)

[Evan78]

hmmmm well, true... maybe i'm confused at the problem then.

I just took a "wagon" subframe and suspension and bolted it up to a "sedan" and the track was all the same (was doing a FWD to AWD swap)

but, it would seem that in the prototype pics. the knuckles aren't used, and the only thing used from the engine out, is the Axles... and if I'm not mistaken Impreza Axles are the same, no matter if it is the Impreza Outback Sport, or the Impreza Sedan. (now Legacy is different, slightly)Impreza sedans and wagons 2002 and newer have different track widths. What year car are you working on? Subaru hasn't offered a FWD car since the 90's right?

I'm not well versed in the 2001 and older stuff, but others here are.

[PhyrraM]

Control arms are wider on '02-'07 sedans than any wagon or any '93-'01 Impeza. This pushed the knuckle out. The actual knuckle is the same on either width.

Because the upper strut mounts on both widths do not move, this means that the strut "leans" more on the '02-'07 sedans. To accomodate this "lean" wide and narrow cars have the knuckle mounting holes (on the lower part of the strut) drilled slightly differently.

If you used all "matching" components you would not notice anything wrong. However, if you used "wide" struts and "narrow" control arms you would find your ability to adjust a proper camber setting greatly diminished, to the point that all the factory adjustment is used getting back to the factory setting - leaving none for extra camber.

I have not played with drive axles, but I *suspect* that there is enough extra travel in either to accomodate a mismatch at factory ride height. Factory part number ARE different for wagons and sedans however.

[Ironhydroxide]

Subaru hasn't offered Fwd Since 96 with the brighton IIRC...

so, Knuckles are all the same, and struts are different..... hmmmm.... mount points are same.... swingarms are different.... hmmmmmmm

ok? well news to me.

on the rear that would mean lateral links would be longer, on the front, entire swingarm assy.

(off to do some research.)

[Twinspool]

What years and parts are interchangeable with the Saab 9-2x? Notable differences that one should be aware of? Minutia?

[PhyrraM]

The 9-2x was based on the '02-'07 wagon. The only notable hardware change wasit had different, Saab engineered, control arm bushings. These should be compatable, but I cannot say for certain.

The dashboard was minorly changed, but if the 818 uses it - I'm sure it will be compatable.

[NonProfit]

Good stuff here!

PhyrraM, got any more tidbits?

[riptide motorsport]

I miss this thread!!

[PhyrraM]

As more Subaru knowledge came to the board, the tidbits started popping up in other threads.

[FinishlineWRX]

Tidbit:

Most 16 and 32 bit ecu's can be tuned with free open source software and a ~150 cable

N/A 5mt transmissions are 4:11 final drive
Turbo 5mt are 3:90

[SkiRideDrive]

Tidbit:

Most 16 and 32 bit ecu's can be tuned with free open source software and a ~150 cable

N/A 5mt transmissions are 4:11 final drive
Turbo 5mt are 3:90

I think the 06-07 turbo 5mt's are 3.70

[RM1SepEx]

don't the rear diffs have the 3.7 ratio as the trans has a 1.1 output ratio to the rear diff?

[Nuul]

Tidbit:
Most 16 and 32 bit ecu's can be tuned with free open source software and a ~150 cable


Also known as a Tactrix (http://www.tactrix.com/index.php) cable.

[PhyrraM]

I'm not sure about the '06-'07 ratios, but the '02-'05 2.0 WRX had a 3.9:1 final drive in the transmission, a 1.1:1 center differential ratio, and a 3.54:1 rear diff ratio.

There are both 4.11 and 4.44 ratio transmissions, in both N/A and Turbo form, out there also from non '02-'06 WRX cars. (Legacy, Outbacks, Bajas, Foresters). They will all work with no (to minor) mods for those that wish to try something different.

[FinishlineWRX]

The ratios stayed the same till 07. 08+ got a longer 1-3 I believe. I forgot about the 3.70 final in 06-07, Went back to 3.90 in 08

The 02 was known to be the weakest of the 5mt and late 03 the gear width changed.

Has there been any word as to what axles will be used? The older 2.0l cars had male stub shaft and then changed to female.

[PhyrraM]

.......Has there been any word as to what axles will be used? ......

Details are not there yet, but we do know they will keep the rear knuckles/hubs in the rear. So a hybrid axle using the front inner joint and the rear outer joint is likely. I'm not sure if that means a custom FFR provided shaft or if one of the stock shafts can be used.

[Arrowhead]

When changing the timing belt on a DOHC DO NOT let the cams spin freely. The engine is an interference design and you can wreck your valves if the cams accidently spin on you. Even if the pistons are moved off TDC, the exhaust and intake valve can kiss and bend the stems if the cams are moved independantly. The Subie experts will probably have better info, but I had a close call with this changing the belt on my son's '02 WRX.

[PhyrraM]

When changing the timing belt on a DOHC DO NOT let the cams spin freely. The engine is an interference design and you can wreck your valves if the cams accidently spin on you. Even if the pistons are moved off TDC, the exhaust and intake valve can kiss and bend the stems if the cams are moved independantly. The Subie experts will probably have better info, but I had a close call with this changing the belt on my son's '02 WRX.

This is true, and care must be taken when doing this work - especially when removing the belt. However, Subaru has done what they can to eliminate most of the risk.

First, there are two sets of timing marks, and you do not use the TDC ones when installing the belt. The marks that you use when installing a belt put the pistons well down the bores and out of harms way. Second, Because there is only two cylinders per camshaft it easy to find a 'resting spot' that leaves all the valves closed while doing other work. Third, if you install the belts around the sprockets in order - then the risk of valve to valve contact is minimized. I use large clips to keep the belt in the correct spot one each pully while I wrangle with the next. 3 of the 4 are pretty easy, however, one needs to be "high" on a cam and likes to spin if not careful.

[Funky]

I know that Subaru recently switched from belt to chains (to drive cams) on the new WRXs, but I don't understand why don't ALL manufacturers use chains instead of belt in ALL engines.

This was one area I never had to worry about with Speed3...

[riptide motorsport]

Belts are actually stronger and more durable with less strech than chains..........Steven

[StatGSR]

^ pretty sure that would be the opposite of my opinion but oh well....

[riptide motorsport]

Belt Drive Systems
The hot cam drive setup with many drag racers is a belt drive system. Instead of using gear sprockets and a chain to turn the cam, a belt drive uses ribbed pulleys and a ribbed synthetic rubber belt reinforced with carbon fiber. Belt drives are available for most common pushrod engines (including Chevy LS), as well as most common aftermarket performance blocks. Various belt lengths and pulley diameters are available to accommodate different applications and variations in belt tension.

Belt drives are expensive, costing up to six to 10 times as much as a chain and sprocket cam drive, and three to eight times as much as a gear drive because of the machining required for the front engine cover. However, belt drives do offer a number of important advantages.

Easy adjustability is one. A belt drive runs dry and requires no lubrication as chain drives or gear drives do, so it can be left open and exposed. For drag racing, this is no problem and allows quick cam drive adjustments as well as belt inspection between runs. Adjustment bolts on the cam pulley allow the cam to be advanced or retarded as needed to fine tune the engine’s power curve for prevailing track and traction conditions. For other types of racing that allow belt drives, a dust cover is usually necessary to protect the belt from dirt or debris that may be kicked up into the engine compartment.

A belt drive does require the installation of a front cover seal plate and oil seals behind the crank and cam sprockets to keep engine oil where it belongs. The front plate is machined to fit specific block applications, including standard blocks and aftermarket blocks with a raised cam bore. The more complex the cover, the higher the cost of the kit. Some belt kits are available with torrington bearings or even ball bearing thrust bearings for the cam to precisely control cam end-play.

Belt drives are also quiet (much quieter than gear drives) because of the rubber belt. Another advantage is that the rubber belt minimizes harmonic vibrations that can be transmitted from the crankshaft to the camshaft (a problem that twin idler gear drive systems can experience at high rpm). The reduction of harmonics means more stable valve timing and no loss of power.

Belt drives also create less internal friction than chain drives or gear drives, which reduces parasitic horsepower losses inside the engine. Another advantage with belt drives is that they make it easy to use a front-mounted distributor. This gives you more flexibility in planning the overall configuration of the engine, and comes in handy if an engine will be equipped with a long supercharger that would otherwise interfere with the location of a stock distributor. The belt drive can also be used to drive a front-mounted fuel pump.

The trade-off with belts is that they are not as long lived as chain drives or gear drives. The belt has a limited life, and should be replaced after a certain period of time depending on use. For drag racing, one recommendation is to replace the belt every 200 runs. For circle track racing, replacing the belt at the end of the season is recommended. For endurance racing, most racers will change the belt every race.

Is belt breakage a risk? Breakage of any cam drive or timing component in racing is always a risk. But there’s no greater risk of breaking a belt than a timing chain. The high tech belt materials (including carbon fiber reinforcing fibers in some belts) can safely handle loads created by even the stiffest valve springs.

One belt drive supplier said their 25 and 27 mm width belts can handle up to 500 pounds of closed seat pressure, and 1,200 pounds of open pressure. For more demanding applications, wider belts are available (up to 36 mm).

The crank and cam pulleys for a belt drive system are typically made of billet heat treated steel. So in spite of their relatively high cost, belt drives have proved to be both popular and reliable with professional drag racers.

[NonProfit]

Gear Drive is yet another option. Tomioka Racing offers an Adjustable Cam Gear (http://www.tomiokaracing.com/index.php/subaru-adjustable-cam-gear.html).

[vozproto]

I just found this thread anew and read through all the posts.
I think everyone has some good input in here. But the original intent of this thread got threadjacked.

The intent of simple, concise and digestable tidbits is lost.

I much preferred PhyrraM's original concept.
I say we give PhyrraM his own locked thread. :D

[Evan78]

Gear Drive is yet another option. Tomioka Racing offers an Adjustable Cam Gear (http://www.tomiokaracing.com/index.php/subaru-adjustable-cam-gear.html).Those cam gears are driven by a belt.

[PhyrraM]

I believe Subaru switched from belt to chain to gain usable space on the front of the motor, to extend service intervals, and to reduce NVH (under a metal cover vs. plastic). I'm sure that both belts and chains are engineered (by Subaru) to basically the same strength and speed ratings.

Why an enthusiast swaps a V8 to a belt has no practicle bearing on why Subaru made a wholesale change in it's OEM designs.

[Xusia]

You're right, it doesn't answer the original question. I think he was just pointing out the merits of belts to those who didn't know much about advantages/disadvantages of each. I appreciated the information. :)

[Evan78]

I thought it was informative even if it isn't Subaru specific. Here's an article on EngineBuilderMag.com (http://www.enginebuildermag.com/Article/94901/cam_drives_and_timing_components.aspx) that has additional info on the topic, though still not Subaru specific.

[PhyrraM]

Didn't mean to say the info wasnt needed or knowledgable. By all means, keeping people educated is always a good thing. I was just stating the reasons Subaru went to a chain.

[snowphun]

I know that Subaru recently switched from belt to chains (to drive cams) on the new WRXs, but I don't understand why don't ALL manufacturers use chains instead of belt in ALL engines.


This is incorrect, all WRX/STI models are still timing belts.

[StatGSR]

Thats because they are the only ones still using ej engines...the 2012 wrx and sti are still using the old impreza chassis, i have not yet seen what the plans are for 2013.

[snowphun]

Thats because they are the only ones still using ej engines...the 2012 wrx and sti are still using the old impreza chassis, i have not yet seen what the plans are for 2013.

Right, so they all use belts, MY02-MY12. And all info suggests the MY13 will be the same model. :)

[Evan78]

Has Subaru confirmed that they'll offer a turbo version of the engine (FB20) used in the new Impreza?

[Sebxb]

Has Subaru confirmed that they'll offer a turbo version of the engine (FB20) used in the new Impreza?

If you go to Japan's Subaru website, you can see they just came out with a direct injected turbo FB20 in the Legacy. I guess that it will come to North America sooner or later... (hopefully next year).

Here's the link: http://www.subaru.jp/legacy/dit/performance/

296 hp, 295 fout pounds of torque.

[Evan78]

Wow, and they say it makes 295 lb/ft from 2000 to 4800 rpm. Thanks for the link.

http://www.subaru.jp/legacy/dit/performance/images/pict02.gif

[Sebxb]

Wow, and they say it makes 295 lb/ft from 2000 to 4800 rpm. Thanks for the link.

http://www.subaru.jp/legacy/dit/performance/images/pict02.gif

Hey no problem!

Yeah, you get the typical high and hyper-linear torque curve that comes with direct injected turbo engines like VWs (200 ft*pounds) and the Mazdaspeeds (280 ft*pounds) to name a few.

Hopefully they do something similar in the STI version of the new BRZ!

[riptide motorsport]

that is too cool! wonder what a crate motor and harness would cost?

[NonProfit]

that is too cool! wonder what a crate motor and harness would cost?

My understanding was that Subaru did not sell complete crate motors.

[PhyrraM]

Bumping this one final time. Maybe some of the Tidbits can help with the current FAQ threads.

It was fun to watch how over the last two years the forum has gone from a mostly V8 based FFR group just learning about Subarus to the blend we have now.

[Ironhydroxide]

don't the rear diffs have the 3.7 ratio as the trans has a 1.1 output ratio to the rear diff?

no, only 02-05 WRX manual has the 1:1.1 center diff making the front diff 3.9 and the rear 3.545 (funny enough the Automatic SVX was the same way, but we wont get into ancient history here)

[Ironhydroxide]

Has Subaru confirmed that they'll offer a turbo version of the engine (FB20) used in the new Impreza?

the new Forester XT has the new FB20 in turbo setup :cool:

[Desertrunner]

There is a trick to installing Subaru wheel bearings if you do it the wrong way they will fail with in 10,000 miles or less. Happy to explain is wanted.

[Samiam1017]

There is a trick to installing Subaru wheel bearings if you do it the wrong way they will fail with in 10,000 miles or less. Happy to explain is wanted.

Start a how to thread with pics if possible. I'm sure a few people would be interested

[AZPete]

Yes, yes, yes, keep this thread going! I'm one of those V-8 roadster guys learning about Subaru stuff and I just discovered this thread and studied it all. Thanks, PhyrraM and others.
Pete

[Canadian818]

I too just discovered this thread, been reading through it off and on all day. Very informative, thank you.