Snowbum's Build Thread As some of you know, i'll be building an ej20 for my 2.5rs. I am very excited to start this whole process, but my knowledge is limited and my experience is non-existent. I have many many questions..... This subie is going to remain my daily commuter so I need it reliable (I wish i had the means for an insane build). My power goal is 300awhp, is this realistic without sacrificing reliability? I want to go with eagle h-beams and weisco pistons. Are these ready to install out of box, or do they need to be balanced? Can the ej25 intake manifold/throttle body/fuel rail/oil pump work with an ej20 bock and heads? 16g turbo, I'm purty sure that sti pinks flow enough for it, but i could use some feedback I'll have more questions the more i think about it. Thanks for all of your guys' input, it is much appreciated!
Gotta use the intake manifold that matches the heads. Like nuke said grab it all. I would spend the little money it costs to make sure everything is balanced. Better safe than sorry.
The rods and pistons should be very close out of the box, but I would still bring them to a shop and at the very least have them checked. I have received so called matched rod sets before from carrillo and eagle only to find out one or more of the rods were 2+ grams out from the rest. B and A Cylinderhead in Blaine does some top notch balancing and machine work, ask for Matt.
Cool cool, that was my gut feeling. How high of quality are the rod bearings subaru uses? Would they be worth upgrading?
My Wiseco's were all with .5 grams. The Eagle rods on the otherhand do need to be balanced. 300whp on a 2.0L is pushing the limits of what can be reliable on that car without serious leaps in cost. Just tossing in some internals is not going to be the magic potion to reliably drive 300whp daily. You will basically have to delve into every subsystem on the car to support it. Have you thought about a fuel system yet? Clutch? Transmission? Management? It adds up in a SERIOUS hurry. You can ask me(and a few others here) in person some time about what I've got(and the few others) into our cars to reliably support 300+whp. This is a must read: http://www.pandlmotorsports.com/caringforyourvehicle.pdf
Good article piddster. I see where your comming from with the reliability, maybe i'm being alittle bit ambitious for a daily vehicle. I'm well aware i'll have to do some serious changes to the subsystems of the car.
On the subject of Wiseco pistons, just make certain the wrist pin retainer clips are the correct ones for your application. Best thing to do is ask the guy that is balancing your rods and pistons. D&G does good work, and I think I spent 100 bucks on balancing there. I'd have to dig up the receipt. What have you decided to use for engine management? If you have an EJ205 with matching heads and such, I'd be looking for a WRX ecu. Probably an 04+ one, can't remember why though. I learned early on that you can't just stop the plans at the engine, you need to think about how that engine affects every piece of the puzzle. A built motor is only as good as the stuff that's bolted up to it. My 3500 dollar motor project ended up costing about $12k.
haha i know, right? I know **** when it comes to engine managment. I assume i would need the wrx ecu, but where do i go from there? Can the car be tuned from reflashing the ecu? I still dont know if i will need a wiring harness aswell, or if the current one can be modified somehow? I'm definilty not wiring this thing up, i'll leave it to someone who has had some experience. I read that the 6spd tranny wont work with the 5spd reardiff. With a wrx tranny will i need the matching rear diff aswelll, and will the rs driveshaft work with it? Is a 255 lph fuel pump and injectors all i need to upgrade on the fuel system, or will i also need aftermarket fuel rails? Also, if anyone has a wrx cross-member (or know where i can get one) that would be nice
why don't you just do a straight wrx drivetrain swap then open ecu tune that ....it will be easier..and then everything works and you can run the same wheels and everything!
Yeah, you'd need the wiring harnesses, or have someone splice them up for you. The 6 speed would need the R180 rear dif, a shortened driveshaft and new rear half shafts, plus the hubs and rotors from the STi. There are other routes too, but you'd probably want to hit up Nasioc for the ins and outs of that. Yes, the 255 and larger fuel injectors would likely be all you'd need. Fuel rails would be over kill.
You don't need the R180 unless to are planning on rocking serious power to the point of breaking the R160. You just need a 3.90 rear if the 6mt is from '04-'06. The '07 uses a 3.545 final, which matches the WRX 5mt. An driveshaft out of an automatic takes car of that. Depending on what front axels you have you may need the stub axels that pop into the 6mt so you can use the front axels you already have. Thats how I made mine work.
