I've been doing alot of reserarch lately. My friends are talking me into keeping my 95 impreza instead of trading up to a WRX. Originally i wanted to build a 22t but that's pretty expensive. Then i got the idea of the 2.5. I know late 90s they made a 2.5RS for my body style. I'd like to put lightweight, forged and balanced internals so i can have a quick, high rev, high compression NA engine that i can rev all day without issues. Im curious how the block holds up besides buying a 257 WRX block. Then im looking at a $1200 block again. I know there's alot of 2.5 SOHC foresters around here in the junkyards so getting a phase1 would be easy. Or should I hold off for a DOHC 2.5? I intend to have a machine shop work on the block and heads due to h/g issues and run head studs and try to find a stronger h/g. Has anyone seen this done in the gc impreza? (that didnt come with it) What would be involved in the swap besides the ecm, harness and engine? Links to guides would be helpful also if anyone knows any.

You'll be more money into that than you would into a wrx. Just build a frankenmotor or buy a wrx. Once you get through engine management and fancy internals, you'll be about $4000 in the hole and will be making little more power than a bone stock wrx.

It seems my car was meant for a frankenmotor. EJ22 stock with 5-speed awd tranny. if i was to do the frankenmotor i've got a few questions.

 

1: What kind of gains could I get from the build? I read up on the thread here and it said the motor was dyno'd at 125hp? My stock ej22 puts more than that.

 

2: Can i use a SOHC EJ25 bottom end? Is there much difference between phase1 ej25, dohc ej25 and WRX ej25?

 

3: Can i use my ECM seeing as i'll be running my stock heads which means stock intake and components?

 

4: It seems everyone says #1 thing is delta cams. Dont they re-grind your original cams, not sell you cams and dont you need a tune to compensate for them?

 

SOHC EJ25s and EJ22s are a dime a dozen around here so acquiring these parts will be relatively cheap. On that i could just acquire the EJ25, get a 2.5 gasket kit and replace all the seals and such. My heads are re-done and my timing belt and components are new on my engine. It's been all redone exept the bottom end. I could swap all those components over. Seems the frankenmotor would be pretty cheap unless I was to tear into the bottom end. Or unless it needs an ecm tune which nobody around here does that.

Edited June 22, 201213 yr by Recian

It seems my car was meant for a frankenmotor. EJ22 stock with 5-speed awd tranny. if i was to do the frankenmotor i've got a few questions.

 

1: What kind of gains could I get from the build? I read up on the thread here and it said the motor was dyno'd at 125hp? My stock ej22 puts more than that. The build I followed and improved on put down 183whp on the dyno. Stock EJ22 is MAYBE 105 on the dyno. Stock WRX is about 175

 

2: Can i use a SOHC EJ25 bottom end? Is there much difference between phase1 ej25, dohc ej25 and WRX ej25? Look for an EJ251. The EJ25D is known for eating rod bearings. I built off of an EJ25D, but I also went with all new bearings, a 10mm oil pump, and an oil pressure gauge.

 

3: Can i use my ECM seeing as i'll be running my stock heads which means stock intake and components? That's the whole idea behind it. No wiring/ECU swaps.

 

4: It seems everyone says #1 thing is delta cams. Dont they re-grind your original cams, not sell you cams and dont you need a tune to compensate for them?Cores. Either you send them payment and a core charge and send them your old cams. Or you send them core cams and payment. No tune is needed, but you will need to shim for HLAs or adjust your lash for SLAs.

 

SOHC EJ25s and EJ22s are a dime a dozen around here so acquiring these parts will be relatively cheap. On that i could just acquire the EJ25, get a 2.5 gasket kit and replace all the seals and such. My heads are re-done and my timing belt and components are new on my engine. It's been all redone exept the bottom end. I could swap all those components over. Seems the frankenmotor would be pretty cheap unless I was to tear into the bottom end. Or unless it needs an ecm tune which nobody around here does that.

 

See bolded. My franky runs with WRXs all day.

I plan to put ACL race bearings and ARP head studs in it with OEM 2.5 head gaskets when I get it so it's just a matter of finding a 2.5 in good shape that didnt suffer water injestion. Is the oil pump you used an upgrade i can find or is it from a newer EJ25? Another curious question, are there any flow differences between the phase 1 and phase 2 EJ22 heads? I know the spark plugs are in different spots. My car has the "16 valve" v/c's with plugs in the head where i found one with flat covers and plugs through the top part of the covers. Both SOHC

Edited June 23, 201213 yr by Recian

ACL bearings are crap from what I've read. As far as the head gasket is concerned Cometic makes one specific to the frankenmotor. I believe the phase 2 (99+) EJ22 heads flow better, but don't know for certain.

Would the cometics be:

 

http://www.cometic.com/sportcompact.aspx

 

bore:100 MLS .040" P/N: C4264-040 Price:1 $52.76

 

 

So would you recommend OEM bearings or do you know another company? or could i use OEM WRX block bearings?

Edited June 23, 201213 yr by Recian

Would the cometics be:

 

http://www.cometic.com/sportcompact.aspx

 

bore:100 MLS .040" P/N: C4264-040 Price:1 $52.76

 

 

So would you recommend OEM bearings or do you know another company? or could i use OEM WRX block bearings?

 

I used OEM bearings.

 

The part number for the Cometic gasket is H1631SPK040S.

Seems alot of other people mention this number on this build too. It's a shame i cant search it on cometic's web site. I guess i'll have to call them with the number when i get to that stage of the build

My buddy has a JDM DOHC 2.5 in his base FWD impreza and it is pretty damn fast, and a tire roasting machine.

 

use a 99 DOHC bottom end, or 99+ SOHC bottom end. the 99 DOHC is the same as the SOHC (bigger rod bearings) and is usually easier to find.

 

call cometic and order the gaskets over the phone, they come in less than a week. order dealer head bolts and a new set of intake gaskets if yours crumble, for the 2.2 use your heads and that block and all your stock goodies and go to town.

 

Delta cams are a really good investment too.

has anyone here used head studs on this build yet? It seems to be a not so common usage on subarus unless youre running high boost. High compression im sure could aid in the use of head studs if you intend to push it. Unless im missing something.