EJ22T Stroker advice

[lindstromjd]

Can someone point me in the direction of the best build thread for turning my EJ22T into a stroker? I've heard you can either put a EJ25 crank in it and leave the pistons alone, or bore out the cylinders to use a EJ25 piston and leave the crank alone. Are either of those correct?

My engine blew a head gasket, and has about 220k miles on it, so it's time for a rebuild. I figured I'd upgrade as much as I could before I put it all back together, since I already have all the stuff for a TD04 and 440 injectors.

Also, if anyone has actually done this, what parts did you end up using? I'm going to do a full rebuild on the engine if I can figure out what exactly to use.

Thanks.

[PhyrraM]

The traditional stroker is a 2.5 liter crank, custom pistons, and stock EJ25 length rods. I say stock length rods because the stock EJ25 rods are not up to the task if the stroker is pushed so custom rods end up being used. If it's not pushed, just build an EJ22.

That all being said, the only good reason to build an EJ22T based stroker is nostalgia. An EJ257/255 build will be cheaper, more powerful for the same boost and just as reliable.

[lindstromjd]

Thanks for the advice.

The main reason behind building the stroker is because the engine is already going to get gone through anyway, and for the fun / experience of it. And because my buddy and I want an engine that will really scream in his 95 Impreza when we want it to. Not really a drag racing engine, but fast enough to have fun with, and faster than a stock EJ22T.

Sorry for sounding in-experienced here, but what's an EJ257/255 and how would you go about building one of those? Is it based off the EJ22T block? Or completely different?

[SILINC3R]

EJ257/255 is a hybrid engine. the first number is the STi 2.5 and probably represent the bottom end(block). the other number representing the top end(heads) and the WRX 2.5

EJ257 2.5 DOHC (2004-2005) 300HP/300TQ
EJ255 2.5 DOHC (2006) 230HP/235TQ

Also the EJ255 is used in the Leg GT (2005-2007)
DOHC 250HP/250TQ

[PhyrraM]

I only refer to the shortblock. I use the term EJ257/255 because they are virtually the same, especially when built because the only difference is the stock pistons. You need to use the heads that are compatible with whatever engine management you choose.

[Legacy777]

I'd suggest sticking with the EJ22T and putting in Eagle forged rods & Wiseco forged pistons. It's a pretty proven setup, and bumps the compression ratio a little bit.

I'm sure you can always do a hybrid or strocker build, but you're going to always run into small things here and there that will add cost and complexity. The forged internals from Wiseco & Eagle are good options and keep some what of a stock setup for ease of installation.

I know you said you want a little more power, but what your power goals? Do you have any plans for engine management? Engine management is a very critical and key component, and needs to be addressed with the type of build you're looking at doing.

[lindstromjd]

My plans for engine management were pretty simple... I want to get the max that I can out of the engine on the stock ECU set up. I've never done a stroker before though, so I don't even know if those plans were realistic. Still, that's what I'd like to do. Max power from stock management. So you think that if I just build the EJ22T with the forged internals and go with my 440's and TD04 that that would be all I need?

What about boring the cylinders out? Is that feasible (or even possible) with an EJ22T? I'm just too much of a v-8 builder and not really knowledgeable (as of right now, I'm working on it) with the boxers.

[Legacy777]

If you change the injectors out to anything but stock, you will need some additional form of engine management. Some say the stock ECU can handle the 440's, but it's not a great solution. You run rich off boost, and you don't get the precise control of fuel you need.

The best and least expensive option out there is a Robtune ECU. They are modified EJ20G ECU's. Rob may still be doing the final testing and tuning of them, but that's really your best option.

If all you're planning to run is the 440's and TD04 stock internals are fine. I was running 550's and a TD05 around 250 whp. Only reason I have upgraded and rebuilt my motor is due to a head gasket issue and blemish on the deck surface which caused me to have to disassemble the entire motor again.

You can get oversized pistons to go in these motors, and you could get custom pistons built, but I wouldn't recommend boring too much out of these blocks. They do have steel liners, but if you bore them too thin, you can cause hot spotting in the liners, overheating, and other issues.

[PhyrraM]

Agreed. If staying with a stock engine management there is no need for the expense and possible complications of a stroker.

FYI, everything you learned on V8s applies. Compression height, quench, rod ratios, chamber sizes, etc... All the math is the same. There are some techniques that are peculiar to the Subaru boxer motor, but the basics are all the same.

The Eagle/Wiseco combo is affordable and proven. It will hold 400+HP (350+ @wheels) if you get enough air and fuel into it.

Stroker IS cool, Stroker IS novelty. Stroker IS bragging rights. Stroker is how it was done 8 years ago before Subaru had a "made for turbo" EJ25 sized motor. I built a stroker because I had the EJ22T case and figured I could save some money. NOPE. The details involved added up to more than a core EJ257 to build upon would have cost me.

I'm not saying don't do it. But define your goals first. If the stroker fits in your goals (novelty, nostalgia, "just wanna") then do it. But if your under the impression that it's the strongest or cheapest build, think twice.

[kimokalihi]

My plans for engine management were pretty simple... I want to get the max that I can out of the engine on the stock ECU set up. I've never done a stroker before though, so I don't even know if those plans were realistic. Still, that's what I'd like to do. Max power from stock management. So you think that if I just build the EJ22T with the forged internals and go with my 440's and TD04 that that would be all I need?

What about boring the cylinders out? Is that feasible (or even possible) with an EJ22T? I'm just too much of a v-8 builder and not really knowledgeable (as of right now, I'm working on it) with the boxers.

It sounds to me like your goals are unrealistic given the information you've provided. You're not going to be making much power at all with a TD04. If you are set on using that turbo you might as well keep the engine completely stock. Rebuild it if it needs it and only if you don't plan on upgrading anything in the future. I say this because if you're going to rebuild it, you're going to be spending a lot of money anyway, so might as well spend some more and actually build a real engine and you should sell the EJ22T (it's worth 300-500 just for the case halves) and buy an EJ257 or EJ255 (I just bought a 257 shortblock with a spun bearing for $50 but don't count on it being that cheap) and find some WRX heads and then you'll need stand alone engine management or swap in WRX dash, ECU and harness.

Then you'll have to buy a 6MT because making that much power is going to grenade your transmission sooner or later. Basically if you want to spend $10-12K and for a built engine, sti trans and engine management go for that, if not then you should probably stay stock and scoot around with a TD04 and focus on handling improvements like coilovers or KYB struts and swaybars and lots of chassis bushings and chassis bracing.

[lindstromjd]

So you're saying it's just easier to not go with a stroker at all? The engine needs gone through anyway; it started sputtering on me one day and when I started looking at it, there was anti-freeze in one of my spark plug holes in the head. That, and it's got over 200k miles on it. So it's getting torn apart regardless. I just wanted to do something to it while I had it apart.

No, I'm not looking for ridiculous amounts of power; just more than I have (had) right now. No, I don't want an STI swap, because my car is an OBD 1 Impreza with a 5mt, and I don't want to deal with the electronics differences between OBD 1 and 2 with a swap.

So I guess it is more just for being able to say "I have an EJ22T stroker" engine than anything. Is it really that unreasonable/hard to build one?

[kimokalihi]

No with STI swap you'd need to ditch the OBD1 ECU and harness and do a full conversion or go with stand alone but I'd stick with the STI ECU.

I would not go with a stroker. There's guys destroking their 2.5 blocks to 2.3 to get their engines to rev to 9.5K or something like that. If you just want some more power sell the EJ22T and buy an EJ20G or EJ20K JDM swap. EJ20G is WRX and EJ20K is sti. I think from 95-97ish. Then you can either run the EJ20G/K ECU or you can get your ECU tuned by Rob and squeeze some more power out of it and remove the boost fuel cut and run up to 18 lbs of boost and you get launch control with Rob's tune and you can upgrade to 525cc STI injectors. That's what I would do if I were you. It's the setup I have in my car now but I am going to go 2.5 eventually but the 2.0 is still fun.

[evolutionmovement]

Well, the bore vs. stroke thing is dependent on what you want. Do you want low end (stroker) or high rpm (bore). There's also the consideration of the rod/piston design and the weights of components which will effect the rpms you could pull. Heavier or longer travel will reduce max rpms. If you were going with a stroker, I'd get lighter pistons to help alleviate the issues of the greater piston speeds and I'd build the rest of the engine to go with low rpm power, so a quick spooling turbo not far off the stock one in character and maybe a small compression bump would be what I'd go with. Off the line, you'd kill, but top end would feel like it fell off pretty suddenly. Personally, that's more my kind of engine, as it's a great road warrior and this is a road car, but it's not a good set up for a racetrack, if that's your thing.

[PhyrraM]

As I stated above, "Because I wanna" is a perfectly valid reason for building a stroker.

Here are a few of the details you need to be aware of. I was hoping that they would be uncovered when you did your due diligence.

1. Your Impreza does not accept any factory turbo ECU. You will need to do a piggyback, a full standalone, or a harness merge with a factory turbo one. If your going to do a merge, most folks choose to use '02+ OBD2 stuff because its very serviceable in North America. Earlier stuff never came here so the knowledge base is vastly reduced. Check on some Impreza based boards for better info. (WE, here on Legacy Central don't have to worry about this on first gen Legacies because we basically have '93-'96 WRX wiring.)

2. Phase 1 vs. phase 2. The EJ22T case has the thrust bearing on the #3 journal. The phase 1 EJ25 crank also does, HOWEVER the phase 1 EJ25 crank has only 48mm rod journals and crappy rods. YOU WILL NEED RODS with this combo. The phase 2 EJ25 crank has same 52mm rod journals as all other Subarus, but has the thrust bearing on #5. You will either need to machine the case or the crank for the thrust location change if you choose the "better" 52mm journals.

3. Rod length. EJ25 phase 1, EJ25 phase 2 normally aspirated and EJ25 phase 2 turbos all have different rod lengths. The non-turbo EJ25 rods are longer. The Turbo EJ25 rods are the same length as the EJ20 and EJ22T. This means a cheap rod upgrade for a STOCK EJ22T is a used STI rod. A stroker, with either crank, requires a rod upgrade and/or aftermarket pistons.

4. Pistons. Compression height is the distance between the top of the piston and the piston pin. Subaru played ALOT with this. To maintain a proper quench and compression ratio you will most certainly need a custom piston with a compression height of your choosing. Your choice of cylinder heads also playing into this, of course. The alternative is a rod length of your choosing and a stock EJ22T piston, but then you still have a cast piston. Custom rods are generally more expensive than custom pistons so an off the shelf aftermarket forged rod and a custom piston is likely the cheapest choice. Wiesco makes an off the shelf forged stroker piston, but it requires finding a forged EJ25 phase 1 length rod.

5. Heads and intake manifold. These are completely determined by your choice of engine management. There are LOOSELY based around phase 1 or phase 2. The two are not compatible. DO NOT confuse your choice of phase 1 or phase 2 shortblock assembly with what I just said. The shortblock is completely separate and compatible with either newer or older heads. The heads, however, are not compatible across phase generations of electronics. So the decision making process goes... Engine management? > heads? > Shortblock components? > intake manifold? > Ancilliaries? (turbo, intercooler, etc)

Hope this helps. And good luck with your build.

[lindstromjd]

Thanks for all that extra info. You said the Impreza won't accept a turbo ECU? Is that the case even if I do a full harness swap, since the Impreza is an OBD 1 car? I thought I would just be able to swap everything out of my Legacy and into the Impreza and it would work...

[kimokalihi]

If you swap the harness, yes. You can swap everything from your legacy into ANYTHING so long as you can make it fit and are a good enough fabricator and have the patience and experience to do electrical. The wiring is the issue stopping you from plugging in a different ECU. If you swap the harness you get rid of that problem. OBD2 is where it's at. No headache, tons of support and loads of parts on the market.

[evolutionmovement]

I second that if you're going to get into wiring, you might as well go to OBD2. Absolutely better now and for the future as all cars are still OBD2. The other thing is the creative technology you can bring into the equation down the line if that's something you'd be interested in.

[PhyrraM]

Thanks for all that extra info. You said the Impreza won't accept a turbo ECU? Is that the case even if I do a full harness swap, since the Impreza is an OBD 1 car? I thought I would just be able to swap everything out of my Legacy and into the Impreza and it would work...

There is no such thing as a "full harness swap" unless you can source a LHD Impreza Turbo harness from overseas. Everything else is considered a merge of your "body functions" wiring and the new "engine control" wiring. Subaru never ran two parralel harness for these functions like some manufactures

[Legacy777]

Thanks for all that extra info. You said the Impreza won't accept a turbo ECU? Is that the case even if I do a full harness swap, since the Impreza is an OBD 1 car? I thought I would just be able to swap everything out of my Legacy and into the Impreza and it would work...

The harnesses between the Legacy & Impreza are vastly different, including ECU location. You wouldn't be able to just take the one out of your Legacy and put it in the Impreza.

[lindstromjd]

Thanks for all that extra info. You said the Impreza won't accept a turbo ECU? Is that the case even if I do a full harness swap, since the Impreza is an OBD 1 car? I thought I would just be able to swap everything out of my Legacy and into the Impreza and it would work...

The harnesses between the Legacy & Impreza are vastly different, including ECU location. You wouldn't be able to just take the one out of your Legacy and put it in the Impreza.

Hmm... well, that puts a damper on things...

[JDMSLIK]

2. Phase 1 vs. phase 2. The EJ22T case has the thrust bearing on the #3 journal. The phase 1 EJ25 crank also does, HOWEVER the phase 1 EJ25 crank has only 48mm rod journals and crappy rods. YOU WILL NEED RODS with this combo. The phase 2 EJ25 crank has same 52mm rod journals as all other Subarus, but has the thrust bearing on #5. You will either need to machine the case or the crank for the thrust location change if you choose the "better" 52mm journals.

So your saying if I I go with a phase 2 EJ25 crank to get the stroker effect I will hafto get both the case and the crank machined to fit them together due to the different placements of the thrust bearings. .

1-Will the addition of another thrust bearing weaken the crank?
2-If I manage to get the phase 2 crank into the ej22t case and use sti rods I will not get the stroker effect