SubuGurus: engine assembly options [Archive]

thebeerbaron

06-25-2011, 09:47 AM

As some of you may know, I am an idiot.

By overlooking a minor issue with my donor, I overheated the engine (http://thefactoryfiveforum.com/entry.php?126-The-Donor) and found out this week that the heads are both cracked (http://thefactoryfiveforum.com/entry.php?147-Bad-news). Let me tell you, that's quite the accomplishment!

Since it takes such great effort to crack Subaru heads, the block is now suspect. If the machine shop thinks it's even worth it, it'll go there to be checked out. But in the mean time, I'm trying to look at the cheapest way to get back to a running donor.

Option 1 (assumes the short block is OK):

Two rebuilt EJ20 heads: $500 each ($1000 total)
Short block examined and refreshed by machinist: $500 (wild guess) ($1500 total)
Gasket set: $280 ($1780 total)

Option 2:

Two rebuilt EJ25 heads: $500 each ($1000 total)
New EJ257 short block: $1900 ($2900 total)
Gasket set: $280 ($3180 total)
Tune: $500 ($3680 total)

Option 3:

Used EJ20, low mile, complete: $3000

Option 4:

Used EJ25: $unknown (need to call around)
Tune: $500

All options would get a new timing belt ($100). Options 1 & 2 would probably get new head bolts because I'm worried the current ones are cooked (otherwise I'd just reuse them like the manual says to do). Also guessing that 1 & 2 would get a new water pump, just in case. The timing belt was done recently on the dead engine, so I'm OK with reusing some of the hard parts off that kit. The belt is toast due to the cam bolt extraction process.

Are there cheaper, better options I haven't touched on? I've seen some suggestions that the SOHC motors might have more low-end grunt in the turbo application. What are my options in this vein?

Any input much appreciated, especially if you can cite your sources!

edited to insert option 4, and I forgot about needing a tune on some of these. Question: I have a V1 AccessPort with a couple of maps on it. Will I need to upgrade to the new AP to have a ProTune done, or download current maps?

Steve91T

06-25-2011, 01:12 PM

That really does suck, and I really can't offer any help other than my opinion. Here's how my mind works. Assuming the low end is OK, then I'd find some cheap, high mileage heads for cheap. Then send them off to the experts and have them port and polished, with some over sized valves. Force induction engines love airflow. You may be able to end up with a really nice engine for not a whole lot of money. Tuning is important and I feel they should always be done on a dyno with someone who really knows what they are doing. It's worth every penny.

I'm just going to guess here, but I would imagine that you could have a very healthy, powerful engine for about the cost of a low mileage stock engine.

At least we have probably over a year before the 818 is available, plenty of time to save up some money!

riptide motorsport

06-25-2011, 01:44 PM

craigslist...used motor......$500

Steve91T

06-25-2011, 01:57 PM

craigslist...used motor......$500

Yeah right, probably runs just about as good as the one he's got.

Steve91T

06-25-2011, 02:02 PM

thebeerbaron

06-25-2011, 03:31 PM

Yeah right, probably runs just about as good as the one he's got.

That's my fear. The ebay link is nice and all, but no mention of compression test, no miles, nothing. Worth exploring though.

Q: which engines/bodies are appropriate donors?

Ks2

06-25-2011, 04:11 PM

if you go the ebay route as i did... most used engines on ebay have a warranty requiring them to be installed by a professional shop to count (or just a start up warranty) my suggestion is before you even take it off the pallet do a compression test yourself and if it isnt good send it back (i made the truck driver wait the 10 minutes while i checked one side and my buddy did the other) there is a restocking fee but usually people dont put broke engines on ebay (craiglist on the other hand)

if you do the labor yourself rebuilding a motor can be the economical way, it isnt hard and there are plenty of guides (on the web) having a shop do it will get pricey fast with labor. get with your local subaru club (we are everywhere!) offer some beers and you are bound to get some help rebuilding it

of course if you did that much damage i would also be suspect of the bearings (those should have went before the heads cracked...) you might replace the oil pump to be safe as well (i personally would hot tank the motor) if you rebuild, i wouldnt trust the bottom end and would rebuild it to be safe

readymix

06-25-2011, 10:13 PM

The EJ20 heads fit right on an EJ257 block, so if your heads are fine, as I would assume they probably are, you can simply pick up either a used EJ257 shortblock or get a new one from a dealership. Everything else should bolt right up, there is one hose that doesn't get used in this scenario. But everything else should work just fine. You would need a tune, but there are tuners around your area I'm sure that could OpenECU you to victory.

thebeerbaron

06-26-2011, 12:13 AM

so if your heads are fine, as I would assume they probably are

Heads are cracked. A hybrid would be great, but I think we're a bit beyond that right now.

Too much fine alcohol this evening to be coherent.

What are my SOHC options, and just how viable are they?

Horhay

06-26-2011, 10:14 AM

You will not need a new AP if you just rebuild and get a tune. The V1 can still be tuned (I just recently got my car retuned with a V1).

thebeerbaron

06-26-2011, 10:46 AM

You will not need a new AP if you just rebuild and get a tune. The V1 can still be tuned (I just recently got my car retuned with a V1).

Excellent news, thank you.

StatGSR

06-27-2011, 08:17 AM

What are my SOHC options, and just how viable are they?

There isn't any really, not if you want to stay turbo that is, i wouldn't recommend starting with the NA SOHC heads if you know your going to be running a turbo.

StatGSR

06-27-2011, 08:19 AM

OK, I take it back.

http://cgi.ebay.com/ebaymotors/1999-2001-Subaru-Legacy-Impreza-DOHC-2-0L-EJ20-Engine-_W0QQcmdZViewItemQQhashZitem3a67684e35QQitemZ25084 2992181QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccesso ries#ht_500wt_1182

yea that engines no good for what he is looking for. its an NA motor... (in JDMland they had 2.0 NA engines)

bromikl

06-27-2011, 08:45 AM

I've never rebuilt an engine, and I don't even know what porting is. But I have a 96 Subaru Impreza with a 2.2L that needs an engine. I was planning to replace it with a rebuilt, and rebuild the one I have. I'm not looking at performance options at this time, and this may not be my donor vehicle.

Who has decent prices on rebuilt Subaru engines? How much should I expect to pay?

Thanks.

ZeroDrift

06-27-2011, 09:18 AM

Heads are cracked. A hybrid would be great, but I think we're a bit beyond that right now.

Too much fine alcohol this evening to be coherent.

What are my SOHC options, and just how viable are they?

SOHC heads from a 2.5L engine won't fit on a 2.0L block. They will 'bolt up', but the larger combustion chamber will cause other issues that will interfere with operation. I personally use SOHC heads on both my own turbo Impreza, and my Fiance's turbo Impreza with great success on both. Mind you we both have 2.5L blocks though.

You have many options, but the most simple one is to use the same type of heads that came with your engine and rebuild what is damaged.

thebeerbaron

06-27-2011, 10:38 AM

prematureapex

06-27-2011, 11:21 AM

Just got good news from the local Subaru tuning shop (who I should have called last week). 2.0L short blocks are still available new from Subaru for $1800 or so. So that's that end decided. The shop recommended buying new head castings and having their specialist machine shop carry over all my valvegear for a total of $1600-1800.

A Subaru wrecking yard in the area is selling reman'd heads for $450/each, plus $150 core. Cheaper solution, but am I being penny-wise and pound foolish?

IMHO, good condition used EJ20 heads are all over the place. These motors tend to spin rod bearings. I'd be buying a set of nice, used heads for $400. But that's just me.

A shortblock can be had for $500-800, again, in good condition. Risk buying used parts? Sure. But it's not hard to research your buyer, at least in a forum setting.

Ks2

06-27-2011, 05:24 PM

shop around on that 1800$ shortblock it can be found cheaper and still brand new/oem (1stsubaruparts.com has it for 1770 for example) doesnt save much but every little bit counts subarugenuineparts and subarupartswharehouse are about the same

on top of that, a new set of gaskets and ARP headstuds and anything else (belts hoses pumps or whatever) you want to replace while you have the motor out

of course this can be seen as an excuse to get a bigger better more powerful motor altogether... when my WRX motor went the cost of a JDM STI ej207 wasnt a whole lot more then just rebuilding mine

Evan78

06-29-2011, 03:13 PM

If you're going for a new factory shortblock, maybe you should use a 2.5L, should be about the same price. More money on tune, but worth it.

thebeerbaron

06-29-2011, 04:15 PM

If you're going for a new factory shortblock, maybe you should use a 2.5L, should be about the same price. More money on tune, but worth it.

Updating to the 2.5L was a thought.

My understanding is that to realize any gains from the 2.5L, I'd need to upgrade to larger injectors, go to the VF-whatever turbo, go to a bigger fuel pump, go to fancy cam shafts, etc. And if I was ever going to do any of that, I'd want to swap out the stock pistons immediately for some forged items. Obviously I could just go to the larger block and not do anything but get it tuned. But my understanding is that I'd actually be in a worse place, because the heads/cams from the 2.0 don't flow enough to give meaningful improvement down low, but the extra displacement means the stock turbo runs out faster.

I've ordered the heads, but haven't pulled the trigger on the short block yet. 2.0 and 2.5 are the same price. Anyone want to show me where my pitiful research has gone wrong?

edit - let's also remember that I think the 230+ HP of the stock motor is going to be brutally quick in the 818!

StatGSR

06-29-2011, 04:20 PM

I have never heard that many downside before about stepping up to a 2.5. Only eve heard good things. BTW the 2.5 wrx still uses the same td04 turbo as the 2.0 wrx...

Evan78

06-29-2011, 04:47 PM

You wouldn't NEED to change anything to realize gains in a 2.5L over a 2.0L. You'll just reach the maximum capacities of components faster. As StatGSR mentioned, Subaru has sold 2.5L engines with a TD04 turbo. Just like any other setup, the power curve will be a reflection of all the components, but I see no performance downside to using a 2.5L instead of a 2.0L when keeping all other components the same.

It is true that the TD04 will "run out faster", but that's the same thing as saying it reaches peak flow earlier, which is something people don't generally complain about. If someone asked you if you want to reach maximum torque earlier without sacrificing it elsewhere, what would you say?

Given stock size fueling and turbo, you won't make much, if any additional peak power, but you'll reach max torque much earlier and transient response should be better everywhere. And you'll have much bigger potential if you ever upgrade the fuel system and turbo. You could pickup a used VF turbo and used 2.5L injectors for very little money to add a lot of power.

I'm no expert, but I'll share what Subaru's I've owned:

2002 WRX (2.0L, stock everything except for AccessPort running off the shelf map)
2003 WRX (2.5L bottom end, stock 2.0L heads, header-back exhaust, SR40 turbo, water/meth injection, 330whp/380wtq)
2005 Legacy GT (turboback, upgraded TMIC, AP v2 dyno tuned, 260whp/320wtq)

Granted, none of those are the setup you're contemplating, but the difference in spool and response between the 2.0 and 2.5 is huge. And my impression is from using turbos larger than the TD04, so your response would be even better.

Evan78

06-29-2011, 04:56 PM

I'm sure lots of people have been in the same boat as you, there's got to be someone on nasioc that has installed a 2.5L hybrid with 2.0L fuel and turbo setup.

thebeerbaron

06-29-2011, 05:13 PM

OK, so I really, really, REALLY need to crack open my turbo book, print out the TD04 compressor map, get out a pencil and paper, and figure out WTF I'm talking about. Because I'm pretty sure I have no clue at this point :)

Analysis paralysis.

So the stock injectors have enough wiggle room that the stock turbo and a 2.5L bottom end will never run lean? And the tuning required to ensure this won't cost me power in other places?

The stock turbo will reach peak flow earlier, but the flow is not so great that the waste gate can't keep up?

If I go 2.5 and promise not to go nuts with the power, do I really need to replace the cast pistons, or is that only for the freaks who do SR40 turbos and water/meth injection? ;)

One other thing - if I did this 2.5 bottom end, what map would I drop into the AP to get the thing started? I'll trailer it to the dyno tuner, but I'd need to run it a bunch to make sure everything is ok before going there.

thebeerbaron

06-29-2011, 05:17 PM

thebeerbaron

06-29-2011, 05:35 PM

OK, it's amazing what re-thinking your search terms will do.

Here is a thread that basically describes what I would be doing, except that the dyno'd car has the auto and it made the dyno kind of weird.

Stock WRX with 2.5L bottom end (http://forums.nasioc.com/forums/showthread.php?t=942699).

Me fail Tubo School? That's unpossible!
http://thm-a01.yimg.com/nimage/82f1c2b52788c10e

Evan78

06-29-2011, 06:12 PM

The thing I read that got me off the 2.5 was someone saying that the source of the STi's low-end grunt was due to the AVCS cam-diddling, and that the hybrids were no better in the low end than the stock 2L.

I think I have failed to establish an effective means of telling the good Subaru information from the crap.Oh boy I wish cam magic was effective as adding 25% displacement. I have no idea how much difference AVCS makes, but I would be blown away if is that effective.

OK, it's amazing what re-thinking your search terms will do.

Here is a thread that basically describes what I would be doing, except that the dyno'd car has the auto and it made the dyno kind of weird.

Stock WRX with 2.5L bottom end (http://forums.nasioc.com/forums/showthread.php?t=942699).Hmm, 3200rpm spread between torque peak and hp peak looks pretty nice to me.

Evan78

06-29-2011, 06:24 PM

So the stock injectors have enough wiggle room that the stock turbo and a 2.5L bottom end will never run lean? And the tuning required to ensure this won't cost me power in other places?

The stock turbo will reach peak flow earlier, but the flow is not so great that the waste gate can't keep up?

If I go 2.5 and promise not to go nuts with the power, do I really need to replace the cast pistons, or is that only for the freaks who do SR40 turbos and water/meth injection? ;)

One other thing - if I did this 2.5 bottom end, what map would I drop into the AP to get the thing started? I'll trailer it to the dyno tuner, but I'd need to run it a bunch to make sure everything is ok before going there.

The tune should address most of the issues, boost will just be limited to whatever the injectors can support. Your wastegate question is a good one, and I don't have a definite answer, but I suspect it's fine.

Stock pistons are fine for your use, people make lots of power using upgraded turbos on them. My car had stock pistons, although that engine did fail, it wasn't a piston and it was probably related to the tune and/or water/meth injection.

I have no idea what map you'd use. Ideally, you could load a conservative version of a known good map of an identical setup. Talk to your tuner. If he's no help, try Clark Turner. I bought the modified WRX used, already built, so someone else tackled all those issues.

Evan78

06-29-2011, 06:34 PM

One more example, this time on a manual transmission:
http://forums.nasioc.com/forums/showthread.php?t=1053426

270tq, 220hp. 2.0L setups usually make, 220-230tq, right?

thebeerbaron

06-29-2011, 11:51 PM

More research done, still paralyzed with analysis. The shop that I would have tune this thing (and where I would logically go for my 818 tune) got into a hybrid discussion over on NASIOC and was highly professional and rational. Amazing. Probably talk with them before pulling the trigger on anything.

One question I'm pondering though - for the 818, is this low-end wall-of-torque we're seeing in the hybrid swaps going to be an asset or a liability?

Noteworthy: knowing what the goal is makes it much easier to hit the target.

Evan78

06-30-2011, 12:01 AM

I'd be interested in reading the conversation you mentioned.

I would think the wall of torque could be tuned out if so desired. If the wastegate starts opening as boost builds, you should be able to smooth out the delivery.

thebeerbaron

06-30-2011, 12:31 AM

Start with this post (http://forums.nasioc.com/forums/showpost.php?p=26893016&postcount=62) and proceed cautiously from there.

tk686 is the hybrid owner
kalescustom is the shop that did the hybrid assembly, I think?
EFI Logics is the shop that I would go to. Been driving past them for years, never knew they were tucked away back there.

From their posts in that thread, it sounds like EFI would be able to help me make an intelligent decision about this process and guide me so that the result is something they can tune comfortably. Sounds like a win, perhaps...

Evan78

06-30-2011, 01:37 AM

StatGSR

06-30-2011, 08:56 AM

thebeerbaron

06-30-2011, 11:16 AM

So EFI Logics advocates having the 2.0 heads milled, but argues that raising compression is not a good idea with this setup. Milling the heads increases compression and changes the quench area, I wonder if they recommend a thicker gasket to bring compression back down.

What I think they're actually advocating is not milling the heads flat per se, but milling around the combustion chamber to better match the size-shape to the 2.5 block.

My reading of that was that the tuner could tune around the higher compression, if he knew about it, but that something was wonky with that particular car. Which turned out to be stupidly modified injectors. Who thinks modifying an injector and not testing it is a good idea?

Evan78

06-30-2011, 12:05 PM

You're right, here's the most detailed description they gave of the heads:

With saying this, every Hybrid swap we build, we send the heads out to get the combustion chambers properly CC'd so the compression level stays at stock, while the heads are at the machine shop, we check for cracks in between the valves and around the spark plug thread, if everything checks out, we assmble the engine with stock Subaru STi headgaskets, etc.

I'm not familiar with how the combustion chambers are different and what machining is typically done on this setup.

Although, after all that discussion about heads, putting in good injectors got the guy in the right ballpark despite not doing anything to the heads.

StatGSR

06-30-2011, 12:57 PM

^ the major part of the machining is matching the bore of the cylinder to the cylinder head, the combustion chamber of the ej20 heads is designed for a smaller bore and is therefore smaller than what it should be.

either way, i wouldn't consider it necessary anyway, the CR is still below 9, so its not like its actually high.... and that car was still making 40hp more than a stock sti...

thebeerbaron

06-30-2011, 10:48 PM

Digesting what the folks at EFI had to say. Keynotes were that all of their customer cars have modified cylinder heads or they don't do the build. They would not do this on their personal cars either. The compression ratio is too high, in their opinion, for a boosted engine.

Also valid questions - just how much power is the 818 going to need and is big torque at low rpm just going to smoke tires?

EFI declined to predict what sort of results would happen from doing the engine this way. They've tuned cars like this before, but did not seem happy about it.

Also, V1 AccessPort not tunable anymore.

Evan78

07-01-2011, 12:21 AM

They can't load a custom map on a V1 AccessPort? That's weird. I've got a v2 on my Legacy (other subarus are gone now) and I don't keep up on the latest developments in that world, but I can't imagine why they wouldn't be able to support it. I purchased my Legacy used and it came with a v1 that I got rid of in favor of a v2. The tuner I used (Clark Turner) said he can produce a little bit better results on the v2 when used on a 32bit ECU. I'm not sure which years switched from 16bit to 32bit, but I'm guessing that all the 2.5L turbo engines came with 32bit.

What's the estimated cost of the headwork?

If they say they don't get good results without modifying the heads, I would either get tuned by someone who does or modify the heads. I'm sure you know that it's not a good idea to talk them into something that they say they've not had good luck with.

LS Miata guys don't complain much about traction issues even on 225 tires and they've got more torque everywhere most any mild 2.5L turbo subaru. If you have any traction issues, you'll just have to re-calibrate your right foot a bit. Smooth, predicable delivery is key, and if it comes on too abruptly, you should be able to modify the tune to compensate. It's a lot easier to back the power down than it is to turn it up.

Evan78

07-01-2011, 01:12 AM

I sent the following to Clark via email and provide a link to this thread:

Can you share any recommendations you have on running 2.0L USDM WRX heads with a 2.5L bottom end? Specifically, what are your thoughts on modifying or not modifying the heads?

Here's his response:

2.0 WRX's where all 16Bit. JDM 2.0 are 16bit also
32 bit started with the 04 STI but its was changed to the 1 meg rom in 05 and on. Drive by wire typicaly means 32 bit.

THe worst engine combination that you can come up with is the 2.0 heads with the 2.5 STI short block. The compression is high and the combustion chambers are to small. 2.0 are 49 to 52cc depending on what they are. If you use thick headgaskets you can run this setup but then the quench area is trashed and I still do not like it.

If one must run this combo they should send the heads to EQ tuning to have the 2.0 heads CNC cut to the 2.5 STI heat size. Then you have the correct 57CC volume for the 2.5 block. Then you can use the factory STI head gasket and you have a decent motor that is tunable on pump gasoline.

I actualy like the EJ205 or EJ207 2.0 motors better then the 2.5 STI motor. The 2.5 motor is weak. It needs pistons at a minimum no matter what the end combination.

If they get 2.5 STI complete engines they wont be able to run them properly. The 16 Bit ECu will not control the AVCS and running these without AVCS is a big step backwards. They would need to swap the entire 32 bit ecu and harness to run the engine with the AVCS system ect..

What they can do is to buy a 2.5 STI motor from 04 to 07 and then order some Kelford or other brand NON avcs camshafts and swap them in. Then this will run on the 16 Bit ecu properly.

If it where me, I would just get a good low mile EJ205 engine, Slap some pistons and rods in it. Then run it off a hydra, Link in or AEM and be done. There are many choices of upgrades for turbo and fuel system to make 450hp++ with that and its cheap.

Clark

ATTN: My email address has CHANGED!
My new address is clark@clarkturnertuning.com
UPDATE YOUR ADDRESS BOOK!

Clark Turner Tuning
480-695-2898
TXT message for faster response

thebeerbaron

07-01-2011, 06:45 AM

Evan, great posts. I'll have more to say later today. Great work!

Ks2

07-01-2011, 09:54 PM

there is a reason i highly recommend clark turner tuning...

forced4

07-06-2011, 04:03 PM

Has anyone come across a step by step tutorial on how to build a 2.5L hybrid setup with 2.0 WRX heads? And a parts list? :D

Evan78

07-06-2011, 04:10 PM

Beer Baron: I discovered that JE Pistons makes pistons for this combination. No head work required and I think it might be a better way to go. Nick @ JE is an experienced Subaru owner and can tell you more:

Nick Diblasi
Sport Compact Specialist / Sr. Technical Sales Advisor
JE Pistons / Sportsman Racing Products
ndiblasi@jepistons.com
714-898-9763 x4253

Here's a link: SUBARU EJ257 BLOCK WITH EJ20 HEAD "FSR" (http://www.jepistons.com/Catalogs/Sport-Compact/Subaru/ej257_ej20head.aspx). Part number 291059 or 291060.

thebeerbaron

07-06-2011, 07:04 PM

Evan, those heads are a neat idea. Head machining is $400, getting forged pistons and solving the head issue at the same time for $600 or whatever those are would be a good deal. Still, too rich for my blood when you figure it's $600 for the parts plus $500 for the tune.

I ordered a new 2 liter short block from EFI on Tuesday. Also a complete engine gasket set. Should be ready for the next wrenching session this weekend.

Ordered remanufactured heads from F&S Auto Parts in CT. They should be ready next week.

Yeah, it's boring. But given the inputs I've gotten, it's the right decision.

Now it's a matter of choosing which bits of the old engine get proactively replaced.

Bashing that front O2 sensor seems to have cost me nearly $200. Damn.

Evan78

07-06-2011, 07:40 PM

Well it's certainly the easiest, cheapest, and most reliable way to go. Those are 3 big points. As you said, not very exciting, but neither is dealing with a bunch of unnecessary headaches.

flynntuna

08-15-2012, 09:05 PM

Great info, being a nubie in the subaru world all these threads are a big help. This is another reason I'm thinking of having 2 motors, one for everyday use and another to experiment on. Maybe I'm over thinking this.

metalmaker12

08-16-2012, 08:26 PM

get a another motor. you can use the parts to build another one at some point, or sell the block etc

longislandwrx

08-20-2012, 10:29 AM

Even going the 2.0l route, if you plan on turning up the boost you should still get a set of drop in pistons. for $500 you'll be happy you did.

also you can get that o2 sensor on Amazon for a lot less than $200.

http://www.amazon.com/gp/product/B000C5YD1A/ref=wms_ohs_product

should be the right one.

Samiam1017

09-16-2012, 06:52 AM

Baron. Howed did you make out with this. What exactly did you end up doing? I have a 05 2.0 that I want to refresh the short block. With the the talk on the other forums it get very confusing fast for none subby guys, like me. Have you looked into a short block, long block or did you just change your heads out.

RM1SepEx

09-16-2012, 05:37 PM

did you do a rebuild? You are talking more than I paid for a 70k mile 2005 roll over donor... Just find another motor and use it with parts from the original.

go JDM on EBay..

longislandwrx

09-17-2012, 08:30 AM

Also, V1 AccessPort not tunable anymore.

says who?

BrandonDrums

09-17-2012, 04:11 PM

Not being able to use AVCS is not a reason to avoid upgrading to a 2.5L on your 16 bit ecu. Displacement is displacement. It used to be AVCS was a big deal because there were less of them available so it was a waste to get the hardware and disconnect it when you couldn't use it. Now, the EJ255/EJ257 is way more common than the USDM 2.0L having been on the wrx since 06, the STI since 04, and on the forester xt, legacy GT and outback turbo since around 03/04. Regardless of AVCS, the EJ255/EJ257 heads flow more and the cams are more aggressive than usdm EJ20 turbo heads.

I do agree the 2.0L is in many ways a more refined and 'better' engine than the 2.5L but that's in a weird way. The heads don't flow as well as the 2.5l dohc heads do and the engine geometry makes it feel more rev-happy than the 2.5L does and because it doesn't swallow as much air, the torque delivery feels smoother and more linear. However, the 2.0L becuase of it's inferior heads actually kinda protects itself from making too much power so it just seems more reliable all other parts being equal.

The problem is the bigger 2.5L displacement and more efficient heads means way more airflow and power at a given boost level than a 2.0L. People get airflow and boost mixed up. Maintaining a boost pressure with 25% more displacement means pushing 25% more air from a turbo. That means way hotter air, more chances to knock and way more power which means more stress. Keep in mind that aside from a longer stroke and a bigger bore, the bottom end of a 2.5L has the same size bearings and the same size oil passages as it's smaller counterpart. It can make roughly 25% more power than the 2.0L with the same boost from the same turbo but you're actually pushing the engine so much harder by doing that.

If we focused on the airflow volume rather than boost pressure when discussing engines and the reliability of their tunes we wouldn't have the misconception that the 2.5L is less reliable because it is a better engine. Why do you think Subaru puts it in everything over here?

Samiam1017

09-17-2012, 08:42 PM

did you do a rebuild? You are talking more than I paid for a 70k mile 2005 roll over donor... Just find another motor and use it with parts from the original.
No I didn't do anything yet. Not sure if rebuilding is a better way to go then a factory short block. Or use a Jdm motor. On another thread somebody posted that the harness, ecu, intake and throttle body should stay together, and that any lower end can be used with proper tuning. But I'm not sure what the best one would be for decent power and reliability.
go JDM on EBay..
Who has purchased these from a reliable source. I have never looked into this. And what version ?

BrandonDrums

09-18-2012, 08:38 AM

Who has purchased these from a reliable source. I have never looked into this. And what version ?

I'm sure if you cruise nasioc.com you can find someone who's sourced a JDM EJ207 on eBay. Despite the bad rap that ebay gets, they've really upped their anty on reducing fraud so if you're going to buy one, do your research and buy knowing that if the order isn't as described, ebay and Paypal will come down on the seller so hard they will be begging to give you a refund.

Most of the engines I see on eBay are JDM V7 or V8 ej20's and a good deal of them come with the ecu and all the accessories. A good number of them also come with the 6 speed MT which is worth a shiny nickel on Nasioc

RM1SepEx

09-18-2012, 09:00 AM

I know people that have sourced multiple JDM engines, mostly Hondas and one mitsubishi twin turbo motor... all with very good reviews
check their feedback, find outside feedback and buy through ebay... ebay has big time leverage with vendors that use them as a major source of sales... EBay has a lot to lose too...

Sadly I have just about zero Subaru experience

Samiam1017

09-18-2012, 01:55 PM

BrandonDrums

09-18-2012, 04:04 PM

I guess I'll look for a Jdm. Now should I use the whole package(harness,ecu,motor) or should I just use the short block and use my assories (all stock) Is there any problems with say using a Cobb access port on a Jdm ecu? Also doesn't the Jdm trans have factory LSD what should I look for version/year. What about my dash cluster working with the Jdm harness. I'm looking to get the car together and running with as much factory stuff as possible then upgrading and changing things later to keep it as simple as possible by trying to eliminate changing or modifying to many things at once and then swapping into another chassis then finding out theres issues that takes tons of time to figure out. If that makes any sense.

I'd use the JDM harness and ECU unless yours has AVCS control. It's all going to be out of the car anyway so it's no big deal to use the one that works best.

*edit I forgot to mention but I'm actually not sure if Cobb supports JDM ECU's. They are extremely similar to USDM ecu's but have some emissions control systems disabled, the COBB might not mate with them.

I think most of the JDM turbo engines available on eBay are V7 or V8's like I said and they will have the 6 speed transmission which is essentially the same as the USDM sti tranny which we know FFR has explicitly stated the 818 Chassis will not support.

As it's been fleshed out on other threads, the 6mt can be converted to 2wd and the chassis can most likely be modified to take the 6 speed but it's bigger, heavier and longer so it will probably poke out of the back of the 818's body or at least force some reconfiguration among other pita things.

If you get a good deal on a full JDM drivetrain, you could trade the 6mt and get cash on top for a 5 speed. That could net you 1200-2k to upgrade the 5mt, those things are only 750-1000 in working order and are like 300 broken. Not to mention being able to sell your old manifolds, ECU etc.

Could be a great route for the 818, the EJ207 will deliver torque more linearly and will probably just feel and drive quite well on the 818 even though they don't make as much power as the 2.5L

Evan78

09-18-2012, 05:12 PM

*edit I forgot to mention but I'm actually not sure if Cobb supports JDM ECU's. They are extremely similar to USDM ecu's but have some emissions control systems disabled, the COBB might not mate with them.My knowledge is from years ago, so verify that what I say here is still true. They sell AccessPorts in Japan for JDM ECU's through a Japanese company. US AP's don't support JDM ECU's, but a phone call to Cobb should yield good info. I imagine they can sell you one that'll work or point you to a source.