legacycentral bbs

I want to lower the compression on my N/A ej22 i have had people tell me that all i would have to do is put a thicker gasket and it will work but i was wondering if their is more i should think about doing? I want to lower it about the same compression ratio as the turbo ej22 as i want to turbo my whole car out . . .I wish i could find a parts list to compare the two and see what i could to do but if i cant get it than anybodies advice is highly appreciated

You could get turbo pistons. Why are you trying to lower your NA motor compression?

sounds like he wants to turbo his n/a subie

you'd want turbo pistons since turbo cars run 8:1 rather then 9:1 like the NA's do, thinner head gasket would probably raise comp ratio even more.

I have been thinking more about this haven't had time write anything because just being busy with other projects and studying a litte more on this topic. So i want to boost my car with about 10 to 15 pounds of boost. I at least want to get about 220hp to the wheels or a litte more but no more than 270. Now I have found cometic head gaskets seem to be the way to go but is just replaceing my head gaskets gona be enoff to lower my compression to where i need to be to get the horse power that i want or should i look geting wiseco pistons to? I really dont want to send a whole lot of money on this but if it's gona be better for me to get new pistons then i will.

Well, trying to turbo charge your NA motor is going to cost you a ton of money. Getting thicker gaskets is not going to change your compression nearly enough to run a turbo. Pistons are going to be a requirement and that's going to cost you money. Plus you have to do something about engine management and larger injectors to supply more fuel to keep up with all the air you're going to be cramming into the cylinders. That's going to cost you a fortune. Then you need a turbo, could range from $100-$500+. There's so much work, parts and money involved in that project. I would abandon that idea if I were you. If you want a turbo car, buy one. Or buy a complete (and I mean COMPLETE) turbo engine and ECU and swap it in. Lot less work this way. Also a lot less money and you'll have reliability on your side.

i got some ej20r heads wanting to rebuild them woundering where i can get the gaskets and valves at? for these heads. Also got some egale connecting rods for a good deal. Woundering where i can get the crank bearings. I am thinking ej22t cranking bearings but woundering if i should go with oem or is their better ones that i should get?

Head gaskets? Use the ones for the block you're using. You can get ARP bearings off ebay I think.

to lower compresion you could shave your heads put thinner headgasket in then put arp headstuds that should lower it good

^^^ that will up it, he needs to lower it


I did the whole na ej22 turbo build. on 6psi with a td04, 3inch turbo back, 3in intake, lightweight pully, mani spacers, cams, its hell of a good time. plenty of practical power and tons of fun when u lie into it.

although my set up does need some perfecting. for one it pushes coolent like no other when I over do boosting. otherwise the car runs great on stock em. ive monitored it on my ssm and everything right within check as far as I can tell. ive replaced my hg once and im still dealing with the same issue, im thinking its just the gaskets arnt strong enough for boost next i want to try ej22t hg see if that works. any idea's anyone?

power wise I would guess im around 180 or so at the wheels, its deffinatly quick not like my sti but still fast. rember this is totally untuned set up, with tunning I would bet theres a ton more power to be made. but thats when it gets expensive.

turboing my na legacy cost me right around $800 for eveything. for the power increase and fun I would deffinatly say it was worth it. reliablity is gone though. the whole pushing coolent thing is the biggest pain. I just cant seem to figure it out.

swap the heads to the ej25d dohc units. better flow and lower comp ratio.

i laugh every time i see "turboing your n/a will cost a fortune" I turbo'ed my beater winter impreza for $47, most everything came out of my junk parts pile. on 10psi its faster then a stock wrx.

i wanted to go ej25d but got a really good deal from a friend of mine on the ej20r heads so now thats the route i am going for. Thanks for the info on the arp bearings. Now all I need is new valves and valve cover gasket.

whats the combustion chamber size on those heads? your stock heads are 40cc so it needs to be bigger then that to lower the comp ratio. the 25d heads are 46cc and the ej251 sohc heads are 50cc

from what i readed they're about the same as the ej25d their somewhere in the range of 46cc to about 48cc.

46cc puts you at 7.6:1 with a 22t HG, i wouldnt want to go much lower then that.

Damn that's low. That's gonna be slowwwwww.

thats what my car has, i wouldnt call 300whp slow.

I'm at 18psi with an 18g and it's slow and I am around 8:1 CR on a EJ20G.

MikeyMeyagi wrote:swap the heads to the ej25d dohc units. better flow and lower comp ratio.

I turbo'ed my beater winter impreza for $47, most everything came out of my junk parts pile. on 10psi its faster then a stock wrx.

Can you elaborate on this setup a bit more? What are you using for EM, injectors, etc...?

i am thinking of useing a tdo4 or tdo5 16g. which would be the best to make about 250 to 295hp and not kill myself in gas a friend of mine told me the tdo5 16g would probaly save me more in gas because i won't be in boost that much is this true? or should i just stick with my original plan of useing the tdo4? i would really like to know from someone who done a hybird build but all are welcome to comment.

kimokalihi wrote:I'm at 18psi with an 18g and it's slow and I am around 8:1 CR on a EJ20G.

idk what to tell you, i ran a 13.2@102mph with race weight of 3385lbs with 7.6:1 comp ratio. off boost it has plenty off pull too...

On what ecu?

20G robtune

my buddy dave has the same motor setup in his SS, and on the factory ecu he made 220whp on 13psi with the same compression ratio.

Hmmm...me too. You think an extra 200cc of displacement is responsible for such a differance? Maybe my rings are worn. I really need a different engine apparently. It does not satisfy me and makes me mad that I've spent so much on this car and it's still slow.

so i've been busy getting things ready for my motor build. Saving up and getting parts here and their. I am about ready to get the bottom end done and then my muffler falls off and now i need to get an exhasut from the cat back woundering what i could get that would still be compatiable with the turbo exhasut that i am going to have to put in later.