Don't think I'm a puss, but how will the 2.5 L perform?

[NonProfit]

Hey, just found out about the 818 and I'm impressed. With three little kids I really should be looking at minivans, but will need a commuter car and want to drive something that doesn't look like a half-used bar of soap (most affordable late model cars). I was considering another kit but like this a lot more.

I'm no mechanic but I can swap parts and my brother has done two frame-offs so I have someone I can tap should I need help. I've also seen his $5500 car turn into a $75K+ restoration and I don't want to walk down that path. The single donor should solve that.

I understand the car is still in development, so there is no way to know for sure. But if it really does weigh in around 1800lbs, what would 165hp feel like? (Remember, I should be driving a minivan.)

Also, lots of folks have been posting here about their $5,000-7,500 WRX finds. Am I just looking in the wrong place (http://www.cars.com/for-sale/searchresults.action?sf1Dir=ASC&mkId=20041&mdId=21295&mdId=36843&mlgId=28859&rd=100000&crSrtFlds=feedSegId-mkId-mdId-trId-mlgId-yrId&PMmt=1-2-4&sf2Dir=ASC&sf1Nm=price&yrId=20200&yrId=20144&yrId=20199&yrId=20143&yrId=20198&yrId=20142&sf2Nm=miles&isDealerGrouping=false&trId=25675&trId=25794&trId=25677&trId=25679&rpp=50&feedSegId=28705&searchSource=GEO_SEARCH&pgId=2102&zc=12345)?

Thanks!

[apexanimal]

it will feel like 330 hp in a typical sized car... but lower, and much better handling...


most on here talk about the wrx as a donor, but the 2.5/rs will be quite the performer on a budget... and dead reliable to boot...

[Silvertop]

it will feel like 330 hp in a typical sized car... but lower, and much better handling...


most on here talk about the wrx as a donor, but the 2.5/rs will be quite the performer on a budget... and dead reliable to boot...

Must agree. Figure on a 0-60 time somewhere around 6 seconds, maybe even the high 5's. And if FFR does its job (and they surely will), it will have phenomenal handling. A pretty darn fast car in a straight line, or around a corner as well. Just don't pick a fight with a true supercar............

While most will probably seek a WRX, there will surely be a lot of folks building from NA 2.5RS donors. I'll probably be one of then. Depends on what I find for a donor car, and at what cost. Probably won't be able to resist tweaking the engine a little to get it to 200HP or so, though.

[thane]

Taken from wikipedia, the following may be of interest:

The 1996 Lotus Elise weighed 725 kg (1,600 lb).[4] Because of its relatively low weight, it was able to accelerate 0-60 mph (97 km/h) in 5.8 seconds despite its relatively low power output of 118 bhp

thane

[Nuul]

With a 165HP engine from the RS you're looking at a weight/power ration of 10.9lb/HP which is roughly a BMW 3 series or Audi TT. Not the fastest out there but a helluva lot of fun.

As for finding the donor, it's been my experience that cars.com is mostly used car lots. Since you're after an RS you should have an easier time of finding what you're after though. You could also try the NASIOC forums. The downside of buying something from NASIOC is that it's probably been modified and run hard. So if you're after something you don't have to touch and just bolt onto an 818 frame then I'd start with craigslist and your local paper. You could also go to a buy-here-pay-here in your town and have them find you one at auction. A lot of those guys will sell it to you for 500 over auction price.

[Etos]

The 251-3(that's the engine code for the non turbos) is a very stout engine. Even in the impreza it's quite a performer and not a let down for a regular car. It's got torque that's for sure. It's got torque cause it's a SOHC and not DOHC. Doesn't rev as high but still, torque is torque. Believe it or not, it can hold it's own vs an unmodded WRX, not falling that far back behind it at all.

You should be able to use earlier model from 1998 and above as a donor. Also going NA means more gas milage and it is a commuter. The only problem you're gonna face is the wait time for a non roadster.

One thing people could also do is run some cams on the NA motor and really give the thing ALOT of torque. Dom from MPS was telling me he knows a great cam for the NA motors that really brings it alive big time, I'll have to ask him what cam that was again and share.

[Nuul]

Dom from MPS was telling me he knows a great cam for the NA motors that really brings it alive big time, I'll have to ask him what cam that was again and share.

I'll probably be sending some business their way soon. I know they do remote tuning for so he's on my short list of people to call for that. I don't suppose you know if they do the head CNCing for 2.0L heads by chance? I really need to call MPS to find out what they can do, I know Dom is pretty much THE guy to talk to about hybrid engines.

[Etos]

I don't believe he does remote tuning. I asked for this a couple years ago and all he provides are tunes based on tunes he's done for customer cars. He really doesn't like doing it cause he doesn't like going back and forth with customers asking for small changes in the tune. Maybe he changed his mind in the last couple years though so perhaps he does now?

I don't think do any inhouse CNC though they do some hand work on head chambers. They source out stuff for PnP, sleeving, balance, etc.

Dom and Micah are pretty much THE guys for anything subaru engine wise. Great guys all around and they not only know their stuff, they know what they don't know and keep pushing the envelop. Dom also owns up to his mistakes and doesn't leave you hanging dry. Micah has been working on a motor that will spin to 10krpm AND produce 900hp. They're torture testing the design right now with a few shops like TiC.

[riptide motorsport]

I'm going affordable to start and upgrade later..Steven

[Evan78]

The 253/5(that's the engine code for the non turbos)EJ255 is a 2.5 DOHC turbo motor. 251, 252, 253, and 254 seem to be 2.5L non-turbo models, all according to wikipedia, so take it however you wish.

http://en.wikipedia.org/wiki/Subaru_EJ_engine#EJ25

NonProfit - just fyi, US turbo subarus have been using nothing but 2.5L engines for many years now, so some people might assume you're still talking turbo engines if you just say "2.5 liter".

[Etos]

EJ255 is a 2.5 DOHC turbo motor. 251, 252, 253, and 254 seem to be 2.5L non-turbo models, all according to wikipedia, so take it however you wish.

http://en.wikipedia.org/wiki/Subaru_EJ_engine#EJ25

NonProfit - just fyi, US turbo subarus have been using nothing but 2.5L engines for many years now, so some people might assume you're still talking turbo engines if you just say "2.5 liter".

oops, mistake I didn't catch.

2002-2005 had the 2.0. True that for 6 years now it's been 2.5l but the first 4 years were 2.0s. Also the 06+ is going to be very hard to find for 5k. More realistically you'll find a full working 06 at cheapest for around 9k. Also the control arms from 08+ will not fit.

[apexanimal]

I'm going affordable to start and upgrade later..Steven

i think i might be doing the same...

[Xusia]

It makes a lot of sense. An Impreza RS donor should be quite a bit cheaper, and I think the chances of it being un-abused are much higher. Most of the WRXs I've seen have had a hard life...

[jimgood]

The Mazda Miata is almost universally considered fun to drive. The 818 will be 400-600 lbs lighter with around the same power if you use the 2.5. And the way FFR designs chassis, it's guaranteed to handle well. Your first drive in the 818 you build will plaster a smile on your face that couldn't be wiped off if you got fired from your job and your dog died on the same day.

[NonProfit]

Thanks for the help! Six second 0-60 is fast enough for me!

[RM1SepEx]

Check out this thread for N/A Subaru performance mods....

http://forums.nasioc.com/forums/showthread.php?t=1022154

Cams, header, intake, some programming... sweet N/A motor

[Nuul]

I don't believe he does remote tuning. I asked for this a couple years ago and all he provides are tunes based on tunes he's done for customer cars. He really doesn't like doing it cause he doesn't like going back and forth with customers asking for small changes in the tune. Maybe he changed his mind in the last couple years though so perhaps he does now?

He may not anymore, there's a link on their website (http://www.maxwellpowerservices.com/services.htm) saying they will for $100. I've not emailed them though so it may not be up to date.

[BipDBo]

Very dependably.

[BrandonDrums]

In my opinion, it's better to tune the car yourself then to pay for remote tuning. Once your datalogging and preparing the data to send to a tuner using RomRaider and OpenECU and Learningview...you can just take it one step further and read up on how to tune it yourself and get a better tune for it. Learning how to translate data is 80% of the challenge in learning how to do some basic tuning. Take boost out of the equation and it's like learning how to drive on an automatic.

When you're just upgrading basic parts like the intake, injectors, exhaust...90% of the time spent tuning the car will simply be getting those dialed in so you can hit partial and full throttle fueling targets. Then from there, you tweak your fuel and timing targets to find the right balance between power and knock/ping headroom. Just a guess based on my experience, I think most tuners on a 2.5 RS would end up with max-load AFR targets of 11.5 and max-load timing advance of 18 degrees before top dead center give or take.

At the very least, you can use RomRaider's tools to tune the MAF and Injectors and Tip-in throttle enrichment. Then take it to a real dyno to get the power dialed in as RomRaider literally can auto-tune your MAF.

The knock detection system on Subaru's are pretty darn good. If you just make small small changes and do your research you can get good results and have the peace of mind when you're done because you know EVERYTHING your engine is doing in every situation. It's a great feeling.

[StatGSR]

. It's got torque cause it's a SOHC and not DOHC.

yea, that's just not true..... cam design can create torque, but just because it has a single over head cam doesn't mean it will have more torque than a double... the old ej25ds had damn near the same amount of torque as the first SOHC ej25s but they were still DOHCs....

[Oppenheimer]

yea, that's just not true..... cam design can create torque, but just because it has a single over head cam doesn't mean it will have more torque than a double... the old ej25ds had damn near the same amount of torque as the first SOHC ej25s but they were still DOHCs....

I was thinking along the same lines, number of cams doesn't create torque. But thinking about it more, SOHC is typically 2 valves/cylinder, where DOHC is typically multi-valve, 4 valves/cylinder, etc. Less valves typically means less total valve area, which at a given rpm means more air velocity compared to otherwise same engine with more valve area, which typically means more low end torque. So there actually is some merit to what he is saying. Of course, in the real world a number of variables might exist between a given SOHC and a DOHC, besides just the number of cams/valves, that could make it difficult to make a direct compare of SOHC vs DOHC with regards to torque.

[TCL1999]

I have no doubt that you can make good power from a N/A 2.5L motor, and that the 818 will be a ton of fun to run in the sun - BUT - will it get that same WRX rumble? Is it purely the exhaust pulse phasing that matters or does the turbo affect the sound somehow? 'Cause if it doesn't sound like that, I don't want it! :) That may seem like a stupid reason, but I love the distinct sound of the WRX. You can tell one from a mile away because it sounds completely different from everything else on the road.

[StatGSR]

SOHC is typically 2 valves/cylinder, where DOHC is typically multi-valve, 4 valves/cylinder, etc. Less valves typically means less total valve area, which at a given rpm means more air velocity compared to otherwise same engine with more valve area, which typically means more low end torque.

Every EJ SOHC has 4 valves per cylinder. In fact, any decent SOHC that i can think of that has been made in the last 20 years has 4 valves per cylinder...

[PhyrraM]

....- BUT - will it get that same WRX rumble? .....

No worries. Yes it can. And with factory headers it will as long as the rest of the exhaust is free flowing.

[PhyrraM]

SOHC usually requires some type of rockers, while DOHC is usually direct acting on the valve.

So, the one of the main original reasons for many manufactures to go DOHC is recipricating mass, and the impact it has on RPM and ability to rev 'freely'.

There are also packaging concerns regarding port shapes (and volumes) and valve placement (and angles) in the chamber that can be accomodated easier without rocker arms and such "in the way". The traditional "hemi" head is much simpler to accomodate with a DOHC design, for example.

Also, in our modern world, it's much easier to independantly control intake and exhaust phasing when they are operated by seperate sticks.

All that said, if you can design around the packaging constraints, SOHC will open and close valves just as well as DOHC. And in Subarus case, on the bread and butter non-turbo 2.5s the '00+ SOHC design is generally considered (stock-for-stock) better than the previous DOHC design.

[StatGSR]

^ excellent way of putting it PhyrraM and i agree 100% with what you said

[jayguy]

Every EJ SOHC has 4 valves per cylinder. In fact, any decent SOHC that i can think of that has been made in the last 20 years has 4 valves per cylinder...

I guess it depends on your definition of "decent", but the majority of 4.6L V8s made by Ford from '96 thru '04 were SOHC engines with 2-valves per cyl. They also made 3-valve SOHC motors. I'd say the Mustang 3-valve is a pretty "decent" motor. Lots of 2-valve SOHC Mustang motors in Factory Fives.

[Xusia]

I was going to say something similar. In my experience, the vast majority of SOHC engines are 2 valves per cylinder...

[Xusia]

You can tell one from a mile away because it sounds completely different from everything else on the road.

That's really funny to me because that's exactly why I DON'T want that sound. I don't want people to know it's a Subaru engine. I want them to wonder what just handed them their ***! :D

[StatGSR]

No worries. Yes it can. And with factory headers it will as long as the rest of the exhaust is free flowing.

well if you really want the boxer rumble you will want a set of unequal length headers (can be had for very cheap all over the internet and ebay). The oem equal lengths do not sound much like a wrx IMHO. search youtube for for subarus with a unequal length header or "UEL header" and you can judge for yourself.

[TCL1999]

Yeah, I have a N/A 2.5L Forester, and it sounds nothing like the WRX. The whole EL, UEL header thing is probably a moot point anyway, because I'm going to guess the 818 will require a custom exhaust supplied by FFR anyway. I suppose with the turbo motors they'll probably utilize stock exhaust through the turbo, then custom turbo back. Who knows what the plan is for the N/A motors?

[Etos]

The NA boxer engines still have a boxer rumble. Not as much as a turbo version but it's still there. You just need an exhaust to un-muffle it. Even the beetle had a boxer rumble.

[LS1RX7owen]

I'd bet the NA 2.5L and even the 2.0L would be a hell of a lot of fun in the 818, especially if there is a big price difference with buying a non-turbo donor car

[PhyrraM]

At 1800 pounds or less, even the 1.8 liter, 110 HP base '93 Impreza motor will be fun.

Hell, 130HP 2.2liter '89-'94 Legacies can prolly be found for close to $nothing$ and will have 90%-100% of every 818 part you will need. Those years of Legacies all had 4 wheel disc brakes (unlike some Imprezas), good final drive ratio (4:11 vs. the 3.9 of the WRX, debatable in a 1800 pound car though), and the 2.2 is still considered the most bulletproof Subaru motor ever built.

[NonProfit]

Hell, 130HP 2.2liter '89-'94 Legacies can prolly be found for close to $nothing$ and will have 90%-100% of every 818 part you will need.


torquestats.com (www.torquestats.com/modified/index.php?pid=calculator&action=calculate_times&drive=RWD&bhp=130&weight=818&submit=Calculate) estimates respectable performance for such a low-buck build:
RWD - 130bhp & 818kg
Power to Weight: 161 bhp/ton
0-60: 6.3
0-100: 19.1
60-100: 12.8
1/4 Mile ET: 15.07

In another thread, PhyrraM correctly point out:

Don't forget when doing our internet maths that whatever an engine/turbo/tune/etc puts 'to the wheels' in an AWD Subaru is likely to be measurably greater 'to the wheels' on a 2WD 818.

FFR is saying 02-07 for the single donor. After release, I'd sure like someone with the knowledge to detail just what configurations will work.

[Evan78]

At 1800 lbs, you only need 100-110 hp to match the power to weight ratio of a 90's Miata. I have plenty of fun in my 99 with stock power.

[Xusia]

... and the 2.2 is still considered the most bulletproof Subaru motor ever built.

That's an intriguing option. Will it fit? (I would assume, but you never know) What about performance options?

I've been giving the NA 2.5L some serious thought, and based on a previous write up it seems like you could get it 200hp for a reasonable cost. If the 2.2L is similar, it would be another viable option...

[Etos]

That's an intriguing option. Will it fit? (I would assume, but you never know) What about performance options?

I've been giving the NA 2.5L some serious thought, and based on a previous write up it seems like you could get it 200hp for a reasonable cost. If the 2.2L is similar, it would be another viable option...

The "bullet proof" 2.2 is the turbo version. It would need a turbo to run well from low compression. Yes it will fit, any 4 cyl EJ will fit. The NA 2.5 is a seriously under rated engine. It moves along very well in a 3200 pound AWD car perfectly fine. Stick it in a 1800 pound RWD car and it'll still be a seriously fun car to drive.

[StatGSR]

The "bullet proof" 2.2 is the turbo version.

that's not entirely true, the old 22t has a bullet proof block (its the only fully closed deck block that has ever been available in the US). in stock form, it really performs no better than a newer NA 2.5 but is a little easier to getting a little more out of being its a turbo engine, so several upgrades are cheap and worth while, but with stock engine management, it will get finicky about stupid things, and in reality the tiny heads that come on it will limit it to about 200whp, overall it is a pretty reliable engine if taken care off. But back to my the point i was going to make, the stock NA EJ22s found in 93-00 imprezas and 90-99 legacys is a bullet proof engine from a reliability stand point, they can take a beating and basically be neglected for years on end without so much as a hiccup, heck the early ones are non interference motors, so you don't even have to worry about the engine hurting itself it the timing belt pops. as far as modifying them in NA form to make more power, its a massive waste of time IMO, unless your just thinking about slapping a home brew turbo on it, which if i cant get a ez30 to fit, is probably what i would do. i have seen na EJ22s take 10lbs of boost making over 200whp for 5+ years with nothing more than the stock ecu and a rising rate fuel pressure regulator, and i have personally thrashed the crap out of my own 200K mile EJ22 while ice racing my legacy and it never missed a beat.

[Etos]

that's not entirely true, the old 22t has a bullet proof block (its the only fully closed deck block that has ever been available in the US). in stock form, it really performs no better than a newer NA 2.5 but is a little easier to getting a little more out of being its a turbo engine, so several upgrades are cheap and worth while, but with stock engine management, it will get finicky about stupid things, and in reality the tiny heads that come on it will limit it to about 200whp, overall it is a pretty reliable engine if taken care off. But back to my the point i was going to make, the stock NA EJ22s found in 93-00 imprezas and 90-99 legacys is a bullet proof engine from a reliability stand point, they can take a beating and basically be neglected for years on end without so much as a hiccup, heck the early ones are non interference motors, so you don't even have to worry about the engine hurting itself it the timing belt pops. as far as modifying them in NA form to make more power, its a massive waste of time IMO, unless your just thinking about slapping a home brew turbo on it, which if i cant get a ez30 to fit, is probably what i would do. i have seen na EJ22s take 10lbs of boost making over 200whp for 5+ years with nothing more than the stock ecu and a rising rate fuel pressure regulator, and i have personally thrashed the crap out of my own 200K mile EJ22 while ice racing my legacy and it never missed a beat.

IIRC the NA 2.2s were not closed deck and much different from the turbo 2.2Ts. That's why I quoted bullet proof since when someone is talking about the super nice 2.2s they were talking about the turbo version. IIRC the 2.2Ts were actually the 2.0 short block from a JDM STi that was either bored or stroked out, I don't remember which.

Stock NA ECU boosting an engine, eh. I'm not a fan of purely relying on MBC over EBCS. It's more of an on/off switch feeling then precisely controlled boost.

[PhyrraM]

I am refering to stock motors. There are thousands upon thousands of first gen Legacies well over 200K with only basic maintenance. There are many over 300K. That's what I refer to when I used the term bullet proof. Yes, there are a few issues, but they are well documented and rarely leave you stranded.

The later DOHC 2.5 liter motors have well documented (albeit easily remedied) head gasket problems. Anything even newer with the 'more reliable' SOHC 2.5 is getting away from the basically $free$ status of the earlier cars.

As far as the early North American Legacy turbo motors....yes, they were fully closed deck motors. They were not bored Overseas 2.0 liter motors. Subaru simply cast ALL turbo motors with closed decks for the very early years ('89-'92ish). For the stock power levels, the closed deck was not needed and Subaru started phasing them out. By the time the all new Impreza (with the WRX) came along (in '92) only the 'specials' had closed decks. For the relatively low volume of the North American only 2.2 turbo it didn't make sense to retool for an open deck like the overseas 2.0 motors. Since '04 with the introduction of the semi-closed 2.5 liter blocks, there is little real world advantage to the old closed deck 2.2. Nostalgia, yes...but little else that isn't done better by the semi-closed decks.

[Steve91T]

How much lighter are the n/a engines compared to the turbo versions? I would guess the turbo, piping, and IC could add 50 lbs.

I like n/a engines, especially for track use, no heat soak issues and low stress. Of course that also means low power.

The Elise has 190 hp and just under 2000 lbs. It's fast, but feels like it could use a little more power. I'm afraid the 818 with somewhere around 150 hp will get old.

[StatGSR]

^ this is why i hope an EZ30 will still fit!

[PhyrraM]

How much lighter are the n/a engines compared to the turbo versions? I would guess the turbo, piping, and IC could add 50 lbs......

50 pounds sounds like a very reasonable guess.