EJ 22 Piston Upgrade Question

[Grounded1]

During an engine rebuild has anyone ever used EJ22 turbo pistons in a naturally aspirated EJ22 and then had the head or deck milled to bring it up to the factory n/a compression? Its much cheaper than ordering custom forged pistons for the same application and the turbo pistons are made to take a bit more punishment. Machine shops will say yes to whatever you want to do as long as you have the money. I'm just looking to see if someone actually did this mod and successfully.

[morgie]

you don't want to reuse used pistons.

and for the price of OEM ej22T pistons + pins + locks + ring set , you're better with a custom set !

and that way, you could rise your NA compression a little and get some extra power

you just don't need to order 2618 forged pistons, stick with the 4032 and you may save some $$

contact CPPistons.com .. they will be pleased to answer all your questions

[Grounded1]

THanks for the heads up. I had no intention of using used turbo pistons. The turbo pistons new are still cheaper than custom. Now that were on custom pistons another question comes to mind. I'm a little concerned with getting forged pistons due to the fact they run a little larger piston to bore clearance and these engines (even with piston pin offset) do have a piston slap problem that me be worse with a larger running clearance. The silicone(hyper-eutectic) pistons size up closer to the OEM piston standard. Any thoughts?

[evolutionmovement]

What are you trying to do engine-wise? I don't think you'll need forged pistons unless you're doing something the N/A block would be marginal for.

Steve

[Grounded1]

I have a centrifugal supercharger system in mind. Thats my need for the pistons to be better than N/A. Although I am intrigued with the recent muffler mounted turbo system that Turbo Magazine just highlighted. But I am leaning towards a supercharger.

[morgie]

forged pistons slaps for sure.. at idle and bellow 1000F .. but .. i guess it's the price to pay ! hehe

CP Pistons required .0035" cleancance instead of .001" oem . Other Forged pistons can require up to 0.005" clearance !

[evolutionmovement]

I'd say the block would be the weaker point than the pistons - at least in terms of long-term reliability. The silcone pistons you mentioned may be work for what you want to do if you have good engine mgt. Thena gain, with good enough mgt you may not need upgraded pistons. What kind of boost are you looking to run? IIRC the hyper-eutectic pistons don't require the clearances of forged and are stronger than cast, but more brittle than forged?

Steve

[Grounded1]

I plan to be conservative on the boost. 4 seems to be a good working number for a good result and keep far away from detonation considering the stock N/A compression is on the fringe for a boost application. My understanding is that anything 6 and above needs intercooling and not a smart idea with 9.5 compression.
Can you tell me little more about the brittleness of the hyper-eutectic pistons? Is it a shortcoming in long term durability or is it a something that rears its ugly head during extreme conditions ie: excessive boost?
The bottom end is being balanced and I'm pretty confident the block can handle the low boost I'm going to limit it to. I know I'm attempting this with an open deck 2.2 but there were turbo versions of the EJ22 and from what I've seen in the engine parts manual there were not a lot of major differences in the part numbers of the internals between the two.

[douglas vincent]

I am running 6-10 psi (depending on how correct my boost guage is, and how tight I tighten my belt) on my NA. It is supercharged via a Eaton E62. I have NO aftermarket ecu or anything. Not nessesarily a good idea but it is running and running fairly well. I do have a fuel solenoid hooked up to blow more fuel in at WOT (when the SC turns on) so I am running rich to be safe.

The stock NA 1990 ECU tends to get really boggy after awhile and even though I get something like 30 mph on the freeway (with no boost) it just doesnt have any power at this point unless I hit boost. However, there are many issues I still have not addressed, such as a RRFPR, better fuel pump and of course a piggyback ECU.

[evolutionmovement]

I forget exactly the details of the piston types. I'd have to look it up. It was more a question than a statement as I can't exactly recall. Something about them having a higher silcone content versus lower in other pistons. I think the higher content made it more brittle, but better able to take heat. Like I said, I could be remembering it wrong, so I'll have to see if I can find that article.

The bottom end is very robust design-wise in these engines, but the major difference in the blocks between N/A and turbo is the very significant closed deck design on the turbo. My N/A's cylinders showed definite evidence of walking on the heads gaskets when I disassembled the engine and that's without boost (but a lot of abused miles). I think 4 psi should be allright and I don't know what your longevity expectations are, but they are probably more relaxed than mine.

Steve

[Grounded1]

Thanks for the info Steve. I'll see what I can find out about the hyper-e pistons. I have to bring the heads infir work so I'll talk with the machine shop guys and see what they think. Their suppose to be reputable. I know Subaru has longevity in their blood but I don't expect any reworked engine for performance to go past 100,000 miles if I'm lucky. By then I'll have the other engine in back up. I hear what your saying about the closed deck block but I'm willing to be another EJ22 lab rat with my set up.
Hey Vincent Douglas. Could you post or point me in the direction of a photo of your supercharger installation. All the ones I've seen are on the right side (viewed from driver seat) of the engine compartment. I've toyed with relocating the battery to the rear of the wagon and doing a left side install. I would like to see a photo and get some feedback on your install.