tech questions on a 2.5L swap on a 02 wrx

gixerman1000 · 07-04-2009, 10:26 PM

I am in the process of buying a 02 wrx w/115K miles for $2200, but here's the catch. It has a knocking motor, so i'm trying to clear some things up since i would like to put a sti short block in, instead of another 2.0L.

I take it that i can swap the heads right over from my 2.0L to the sti block, but i am curious in what year block that i need for this swap to go smoothly. also what block i would need that would handle some boost, since i do believe there is a few upgrades on this car already.

it have a full HKS exhaust, K&N air filter setup, much bigger TMIC, Aluminum radiator, Turbo timer, and looks like a brand new turbo.. is there anything else i may need for the 2.5L swap?

mosc · 07-05-2009, 11:56 AM

I think any year EJ257 block will work. Maybe something changed recently but at least 04-07 works fine and I'm pretty sure newer years too.

newtothegame · 07-05-2009, 12:17 PM

Look into the pistons rods, studs, all the things like since you will have the engine open, might as well put the stronger stuff in there so it can handle more later down the road.

gixerman1000 · 07-05-2009, 12:36 PM

I was told that once you split the block then it would be hard to put it all back together right. i was wondering with the sti block and wrx trans, would the sti flywheel fit into the trans just fine or would i have to grind the inside out a lil bit?

04wrxhart · 07-05-2009, 04:11 PM

If your going to put a sti motor on a wrx tranny, you really need to consider upgrading your tranny too. especially sense its a modded 02 wrx and all I have heard about the 02,03 trannys is bad news.

gixerman1000 · 07-06-2009, 08:43 AM

I found a receipt in the glove box saying that the tranny was rebuilt at 20K miles, but for what reason i don't know. i just found a EJ257 block for a 07 STI to go into my car for 1900. the question is do i really want to buy the oem flywheel for that motor or should i get a lightweight flywheel?

Anyone know where i may be able to get and inexpensive 6spd tranny for this car?
I was told everything will switch over and all i have to do is plug a port on top of the block....i think it's the ari port or something like that....anyone know what they're talking about?

mosc · 07-06-2009, 09:18 AM

No, the 6-speed is not a simple swap, there's a lot more that has to be done and the cost is quite high. Generally, it's better to replace the gears in your 5-speed than to deal with an STi 6-speed.

newtothegame · 07-06-2009, 10:56 AM

+1 to that. Just search/google STI transmission swap. Its not just the gears or the gear box, you need the hubs, driveshaft, wire in the DCCD if it has it. Very spendy upgrade/modification.

gixerman1000 · 07-10-2009, 07:26 PM

alright well i guess i'll just try not to boost this motor too much...anyone know if the wrx flywheel will fit on the ej257 or do i need to get an oem one. also will the flywheel fit fine into the 5spd tranny or do i need to do some modifications.

I was looking into some forged kits that come with pistons, rod, wrist pins and rings, but is there a specific one that would be worth the time and money? i have an option between je, cp, wiseco, and cosworth. i believe the je forged pistons are 800 for the kit, or doi really need to do all this with the 07 motor?

I just wanna get everything straightened out so when everything is order it all comes out right, and i don't like doing jobs twice, so i want to get everything right the first time and i really appreciate all the help i've gotten from everyone thus far.

Chase · 07-10-2009, 07:53 PM

The flywheel and all clutch components for a WRX 2.0 will work. Rods are unecassary, but good insurance. I personally did not worry about them, I've not heard of them failing often. Pistons on the other hand... definitely. CP is what I used, and I like them... they're doing their job.

Some misc info I compiled: Hybrid build/rebuild info