legacycentral bbs

First I am looking to run 15-20 psi. What pistons can I use from subaru is there any years that I could get rods and pisotns that are forged that would posibly lower my compression. I know that my 94 NA pistons have limits so I want to do a rebuild so I can crank up the boost budget minded. Any thoughts would be helpful!

Ej22t rods and pistons, about how much boost can they take?

It all depends on your final compression ratio.
You can boost stock internals alot more if your static comp ratio is low.

Maybe someone knows the comp ratio of your proposed setup.

With low compression, stock internals can handle 15-20 all day long.

Here is a handy calculator that gives you a better idea of what Im talking about
http://www.rbracing-rsr.com/compression.htm

you have forged rods from the factory.
the only real factory pistons that you can use are 22t pistons, which will just lower your CR. granted, they have been known to hold up to some serious abuse.
different heads to lower your CR such as ej25 or ej20g are a good option as they will pick you up some flow and let you run a manifold with tons of injector options.
forged pistons- wiseco, cp, etc. big money.
you could try getting your stock pistons or some ej22t pistons cryo treated, which I am going to do. at $7 a piston, it seems like a decent bargain.

What would a gess be for compression if I would run 22t pistons and stock NA heads? Where can I get stock 22t pistons other than subaru? Thanks for the help!

As for getting pistons, you need to post what size bores you have.
They are stamped on the top of the block.
A,B or C.
There will be two letters on each block half.
Like this.
This block has all b's

Is there any way you could be a little more specfic on where to look on the block?
Here is my engine code EJ22EAA4BL if that tells you anything.

Kinda under the alternator.

Napphappy, so those letters correspond to the the same letters somewhere on the pistons? Aren't all EJ22t's the same bore, i.e. same factory parts?

Waldo, I have too many used stock EJ22t internals if you need them. Full setups, cranks, rods, pistons, also stock high end stuff too if you are interested. Weisco, chromoly h-beam rods, ummm droool

Also Waldo, at those boost levels, you might be further ahead to source a good used turbo block. Even minimal efforts to rebuild, hone, bearings, assembly time etc, it can and DOES add up fast. Closed deck EJ20G's and other stuff is out there for a couple hundred bucks, and no assembly required. But if you already have lots of components, this is a good discussion to have.

All subaru motors too my knowledge have the A, B, C piston options. My ej22t block was B's as well.

Yes the pistons will be lettered as well.

You can see the lettering here
http://www.main.experiencetherave.com:8 ... P_4666.JPG

napphappy wrote:It all depends on your final compression ratio.
You can boost stock internals alot more if your static comp ratio is low.

Maybe someone knows the comp ratio of your proposed setup.

With low compression, stock internals can handle 15-20 all day long.

Here is a handy calculator that gives you a better idea of what Im talking about
http://www.rbracing-rsr.com/compression.htm

Taken from the above link.

"On less efficient combustion chambers you may elect to keep your static compression lower and compensate with boost."

Meaning the stock EJ22t heads should require less CR to reamin happy. The better flowing dohc heads should allow for a higher compression ratio.

In the end tuning or lack there of kills motors not boost, nor compression ratio.

For some good reading on the CR issue, check this out.

http://www.theoldone.com/articles/itisd ... heads.html

They offer 12:1 CR motors that run 20lbs of boost. This is all done with a Honda however the pistons head and valves can't tell what they are in.

Josh

The fact remains that with stock EM, I think it would be better to run lower static compression and then compensate with more boost.

And I dont believe that the "flow" of the head has much of an effect on the dynamic compression. But rather cam timing.

Just some thoughts.

Also, (Random Comment) I dont believe anyone here is really "pushing the enelope" as far as technology is concerned. But many are achieving good perfomance by creative use of existing technology.

I just had a thought(uh oh)
couldnt you run ej25 rods in an ej22e to pull the pistons 1mm down in the bores? that would give you ~8.5:1 which isnt great but certainly better than stock and cheap to boot. though wether it is better than ej22t pistons is another story. are the ej25 rods forged?

206er wrote:I just had a thought(uh oh)
couldnt you run ej25 rods in an ej22e to pull the pistons 1mm down in the bores? that would give you ~8.5:1 which isnt great but certainly better than stock and cheap to boot. though wether it is better than ej22t pistons is another story. are the ej25 rods forged?

most EJ25 rods are the same as EJ22 rods, the STi ones I think are 131.2mm or 0.7mm longer than EJ22 rods.

Even if they were shorter, you're effectively changing the deck height which increases quench distance and would likely dramatically effect the performance of the engine in a negative way.

Josh has built a de-stroked 2.5 block utilizing 2.2t crank and rods to bring the CR down and is figuring out EM/conversion stuff as we speak. Last I heard it was running OK at around 8psi.

http://forums.nasioc.com/forums/showthread.php?t=959311

sammydafish wrote:

206er wrote:I just had a thought(uh oh)
couldnt you run ej25 rods in an ej22e to pull the pistons 1mm down in the bores? that would give you ~8.5:1 which isnt great but certainly better than stock and cheap to boot. though wether it is better than ej22t pistons is another story. are the ej25 rods forged?

most EJ25 rods are the same as EJ22 rods, the STi ones I think are 131.2mm or 0.7mm longer than EJ22 rods.

Only the rods from a phase I Ej25 could be used on this sort of project. The big end diameter changed on phase II...

Well to say the least I can not find the letters anywere on my block, I think I have A due to two A's in my engine code but just a guess. So will ej22t pistons fit a NA and will they with stand 15-20 lbs of boost? Finally can you cyro treat used pistons?[/i]

napphappy wrote:The fact remains that with stock EM, I think it would be better to run lower static compression and then compensate with more boost.

And I dont believe that the "flow" of the head has much of an effect on the dynamic compression. But rather cam timing.

Just some thoughts.

Also, (Random Comment) I dont believe anyone here is really "pushing the enelope" as far as technology is concerned. But many are achieving good perfomance by creative use of existing technology.

I think the cam timing definately plays a big part however the quench areas and distance between the head and piston, has the ability to deter knock. There are a lot of numbers thrown around, however I think the stock EJ 22t motor does not fully utialize the quench areas on the head or the pistons.

The motor I built will push this question, meaning the pistons are 2mm into the bore (- deck height). I have mostly rewired a turbo legacy ECU into my 97 outback. It runs and makes boost. There is no audible knock, on who knows how old gas of unknown quality.

BAck on topic, I think you should use a stock 2.2 NA bottom end, thick gaskets and 2.5 dohc heads. Puts you right about 9.0:1. If my motor pops, I will be going this route. With a stock T leg ECU you will have an awesome running car! If you do not have a means of dealing with timing on your NA ECU, that will need to be addressed.

I think if you can make your car run a solid 15lbs with no knock, you will be very happy!

The letters on your motor will be hard to read without taking out the alternator. As they are under the intake manifold/ water cross over area.

Again to the squish height, I think the stock 2.2t gasket is to thick. Nearly if not completely negating the quench areas effect.

Eric from frantic four has had great results running the thin gasket, DOHC heads, on his. It ripped and seamed really resistant to detonation, even towing his motorcycle trailer... hahahahaha.

Josh, we should compare 97 Outbacks sometime.

So are you saying your pistons are 2mm below the deck? That must be crazy low compresion.

I have considered running thin HG, but with a JDM ecu plus a VOS chip, I am afraid of det.

josh, can you explain how squish and quench area effect detonation?

Josh Long wrote:

napphappy wrote:The fact remains that with stock EM, I think it would be better to run lower static compression and then compensate with more boost.

And I dont believe that the "flow" of the head has much of an effect on the dynamic compression. But rather cam timing.

Just some thoughts.

Also, (Random Comment) I dont believe anyone here is really "pushing the enelope" as far as technology is concerned. But many are achieving good perfomance by creative use of existing technology.

I think the cam timing definately plays a big part however the quench areas and distance between the head and piston, has the ability to deter knock. There are a lot of numbers thrown around, however I think the stock EJ 22t motor does not fully utialize the quench areas on the head or the pistons.

The motor I built will push this question, meaning the pistons are 2mm into the bore (- deck height). I have mostly rewired a turbo legacy ECU into my 97 outback. It runs and makes boost. There is no audible knock, on who knows how old gas of unknown quality.

BAck on topic, I think you should use a stock 2.2 NA bottom end, thick gaskets and 2.5 dohc heads. Puts you right about 9.0:1. If my motor pops, I will be going this route. With a stock T leg ECU you will have an awesome running car! If you do not have a means of dealing with timing on your NA ECU, that will need to be addressed.

I think if you can make your car run a solid 15lbs with no knock, you will be very happy!

The letters on your motor will be hard to read without taking out the alternator. As they are under the intake manifold/ water cross over area.

having the quench distance that far will result in almost no squish. That should be terribile for detonation, mixture blending and will change the moment of peak cylinder pressure and the flame front is different. I'd be interested to see the results, though they might not be terrible, they surely won't be good.


my current buildup is a NA 2.2 block with EJ25 SOHC heads, thin gaskets and 0.015" off the heads which will land me at 9.1:1 compression. This combo will take advantage of the quench area, have enough compression to generate good fuel economy and lots of low end torque, yet alow me to run pretty good amounts of boost through my giant front mount. I'm pretty confident I'll be able to keep detonation under control, the big remaining question is if the pistons will be able to handle the pressure needed for the horsepower this combo could make, which should be in the 250+hp range, and maybe even higher.

Was there ever such a thing as a Phase II 2.2?

If you look at a Pauter's site you see that the Big End Bores on the Phase I EJ22 and the Phase I EJ25 are different. Basically you couldn't use Phase I EJ25 Rods with a Phase I EJ22 crank.

I have a full EJ22t rotating assembly (Crank/Rods/Pistons-Pins) sitting around that I would like to sell. I pulled them out of my 2.2t donor shortblock and replaced them with Pauter Phase I EJ25 Rods, Wiseco .020" over pistons, and Phase I EJ25 crank. $150 + shipping takes it.

I also have an un-assembled EJ25 Phase II shortblock that needs to go as well as Phase I DOHC EJ25 heads that are complete.

PM or email me.

Thanks
Brad

The Phase One 2.2 was updated in 97. Some people call this the begining of the Phase Two 2.2.
In 97 it got different pistons(9.7 to 1) and solid lifters.
But Phase Two Came in 99, with the same changes the 2.5 got. With thrust bearing, roller rockers, ect...

And Yes, I believe the 2.0, 2.2 have 52mm crank pins. The 2.5 has 48mm.

Well after doing some talking with subaru today I have gathered that a, b, c are all diffrent grades of pistons so it seemed like that NA's had A's and turbos had B's. After looking at wisecos web site I have concluded that 3.838 in., 97.500mm which is .20 over stock bore pistons would fit my car. Would these fit my stock rods however?

The Wiseco's work with stock rods. They come with pins, rings and circlips.


It seems a shame to go through the work of taking the block apart to bore it with replacing all the seals and bearings, to not spend $300 on some Eagle rods.


With Wiseco pistons, seal kit, engine work, and main & rods bearings, you're in the $1000 range, or more. Why not go the distance?