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What is the best Subaru engine for a performance build and why?
Depends on what your goals are. Do you want a NA or turbo engine. Is this for a performance street car, extremely high boost drag car, torquey rally car, or peaky race car?
most common is an ej257.
Though if it's going in a non subaru(ie you have more engine bay room to work with) The newer 6 cylinder built to turbo spec can be quite mean, the trick is getting the engine management to work correctly.
The old 2.2L Turbo from a 91-94 Legacy Turbo - closed deck, will take more boost than the newer open deck motors. Apparently you add a crank from a 2.5L and you get a 2.35L Hybrid that can take some serious boost!
Are the sixers just two cylinders added onto one of the 4 banger?
RossD said: Are the sixers just two cylinders added onto one of the 4 banger?
I'm sure others with more knowledge will post up, but one of the main differences between the H4 and the H6 is that the H4 uses timing belts, while the H6 uses timing chains.
As for other differences I'll let the Subaru experts speak up. I'm pretty new to the Subie world.
In reply to RossD: In essence yes. The 3.3 is basically the 2.2 with two extra cylinders.
The 3.0 is basically the 2.0 with extra cylinders. The 3.6 is a little more unique has it's rods are sort of a funky shape. The newer 6 cylinders have some electronics that the 4 cylinders don't have, which has taken the opensource tuning crowd a little more effort to figure out.
I have a 2.5 from a 02 Forester that had a piston come apart . I was gonna sleeve it and build it out.
Then I realized that would be very expensive and a non-locked Junkyard motor would be a cheaper route.
Flat torque curve, revvy. boost OK NA OK. Not gonna be a Boost beast though. I want faster throttle response.
In reply to FlightService:
The six cylinder Subarus: EG33, EZ30, and EZ36 are great engines to install and leave alone. I wouldnt build them up without expecting on spending a lot of time, money, or both. The support and performance parts for the SOHC 3 valve EZ engines are just not readily available. I love the EG33 but it just isnt easy to find.
The SOHC ej251 from your Forester wouldnt be my first choice to build either. The head gaskets suck. You can find a few ej255s in the junk yard but you will have better luck trolling Nasioc in the part out sectioin. Unfortunately junk yard engines mostly tend to be the SOHC EJ251 you mentioned. EJ22 turbo engines are not common, can be more expensive, and I have not seen that the closed deck offers an advantage.
If it is going into a Subaru I would build an EJ257. Or if you dont have the money an EJ255 would be fine. Even without "building" though you can get good power from one of those engines with just a few bolt-ons.
If its not going to go into a Subaru I would get one of the twin turbo EJ208s or similar engines. They are dirt cheap because they are a huge pain to use in a LHD Subaru so nobody wants them.
I don't think any Subaru engine is "Revvy," nor do I think any of them are particularly good without boost.
I think the EJ257 is the only way to go really, but make sure you put in a new oil pickup while you have it apart. Nothing like a cracked pickup to ruin you day (and engine).
I had a V4 STI 2.0 engine (EJ20k) in a Subaru Brighton. It was, most definitely, revvy...and hit 8k rpms with vigor. It wasn't especially thrilling below 4k (thanks in part to a leaking downpipe), but throttle response was fantastic, the sound was great...and when boost built it was incredible fun.
He's not going to find one of those in a junkyard though is he.
The eg33 is quite "revvy", from my understanding
Bang for your buck the previously mentioned jdm twin turbos are hard to beat. Nice seen them around 475'bucks before
he isn't going to find an ej20k in a us junk yard, and likely won't find an ej257 there either. At best you are going to find some rebuildable blocks. If you want turbo, you'll find usdm EJ20's for much cheaper than ej255 or ej257 cores. Building a naturally aspirated subie motor is not all that cost effective, but a used power plant with a mild cam upgrade can be lively enough in the lighter bodied subarus. A turbo motor means a different ecu and wiring. So if you are just looking for a junk yard swap, grab another NA 2.5, and do a cam swap and equal length headers and call it a day. 2.0 turbo is your next cheapest route, but a tune is essential for any low end response. There is a night and day difference on the low end between the 2.0 and the 2.5 in terms of response given equivalent tuning, and stock for stock the 2.5 is light years ahead. While you can boost a naturally aspirated subaru motor, the conventional wisdom is that 5psi is the limit for a reliable daily driver and isn't necessarily a cost effective proposition when usdm turbo motors are so readily available.
I have acess in Japan so...
DaveEstey wrote: He's not going to find one of those in a junkyard though is he.
No need to be snippy, he asked for the best engine for a Subaru build and didn't say it had to be a junkyard build. You stated that no Subaru engines are revvy.
I like the EJ20 quite a bit. I've always felt like it's the best swap option simply because of the huge aftermarket it enjoys as a result of having been the STi motor for so long in Japan. Plus, you can get one from an older STi and bolt it into a newer car, if you need to, and they're still plenty powerful to have fun with.
NA: the older dohc 2.5 impreza rs engine
turbo: you cant really beat the new sti 2.5 setup and it comes with the good tranny too.
expect to shell out some bucks for either though, esp the sti engine
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