I am getting ready to build a motor for a 2004 wrx, going to upgrade to a STI shortblock and was wondering if bigger turbo and injectors are a must? What has to be done etc. Going to be using a sti shortblock, 2.0 wrx heads and all the other goodies from a 2.0L motor. Different head studs?Thanks.


Matt,

For some reason I always answer up in the LIC thread, Adam, Noah, I'm going to do it again.
So it seems you in need of a new motor, spun rod bearing? Just a hunch. I too went this route. In Dec '05 my 2.0L took a crap, spun rod bearing, imagine that? To amke a long story short after three new short blocks, I finally ended with a USDM 2.5L. I glad this is where I ended up, the Crawford bobble heads are gone, it's quiet, it gives a bit of confidence. So IMO good call there. As for what you need to build it.... Because it is so involved anything you can put into it now, seriously consider doing. Turbo, I/C, injectors, clutch, flywheel headstuds, thicker head gaskets, ect. ect. Sure you can limp the 2.5L with the TD04, but a VF34 or VF 39 can be found for next to nothing. If your looking to budget build, mod and flowtest stock injectors. Seriously, a one shot build up, should save you money, in installation, down time. Don't forget, with this build you are going to be making quite a bit more torque. The tranny is doomed from the day you turn the key. Expect it to go out.

Thanks for the help, I am actually going to be building this for someone else and he is on a budget. Just wanted to make sure that the stock turbo and injectors would work. Didn't want to get some heat from him because of a mismatched set-up.

if youre going to 2.5l...save up and get yourself the bigger turbo, injectors, fuel pump etc. like ipozestu says. no point to stay with the stock wrx turbo IMO

if youre going to 2.5l...save up and get yourself the bigger turbo, injectors, fuel pump etc. like ipozestu says. no point to stay with the stock wrx turbo IMO

100% agree w/ both of you, why do the upgrade if not for more power while you're there?

-Noah

Is the vf34 the bare minumum for a 2.5l upgrade? Would RA gears be sufficient with the 2.5 set up with vf34?

Is the vf34 the bare minumum for a 2.5l upgrade? Would RA gears be sufficient with the 2.5 set up with vf34?

Doesn't have to be the bare minimum but it would be a nice step-up/upgrade.

RA gearsets would be good.

-Noah