Thread: 400whp, Whats needed?

Looking into a 400whp build and just wondering what I am getting myself into before I get myself in too deep and not be able to finish the project.


U13 bottom end - stock
P11 lowport head - stock
VE oil pump
JWT S4 cams
GT2871R on a GTI-R manifold
JWT ECU
SAFC for fine tuning

Ive been reading and it seems like the stock DET bottoms are way overbuilt but can they handle 400whp with a safe tune? Anything I should look into when putting this motor together? Is it worth buying a DET with a spun bearing and replacing it? Should the rings be replaced as one of the things "while im in there" type deals? What injectors should I go with for a setup like this - yellow STi injectors?

Any input would be awesome.

knowledge and research get to it

You probably want to use something other than the jwt ecu... Maybe Nistune or if you have the money, standalone.

DET block will be fine. No need to do the rings "while you're in there" unless you're taking the head off of the block and are willing to hone the cylinder walls again.

I don't know about an engine with a spun rod bearing. If it was truly just spun, then rebuilding won't be a big deal, but if the bearing was destroyed then you're looking at a very expensive crankshaft fix that I'd personally rather avoid.

To run the yellow Subaru injectors you will absolutely need to run 4-bar base fuel pressure. At 500-520cc they don't flow enough to support 400 WHP at 3-bar. Look for something a bit larger if you want to stay at 3-bar.

Make sure you get the .86AR GT2871R. The .64AR won't cut it. My brother had almost everything you can do to a S13SR motor at 20psi with the smaller version and came out with 360rwhp. Not saying it can't be done its just a LOT easier with the bigger one.

blue balls

Are OEM parts up for the job such as bearings or should I go with after market? Why would a JWT tune be a bad idea for a build like this?

JWT is usually the safer tune, more timing and runs a little richer.

it's not that you can't run a JWT to 400hp but fine tuning will get you there faster.

I have to disagree with Blair on the turbine housing. My friend Codyace has no problem hitting 400whp on his S14 DET with .64 housing 2871R and the spool is better. His dyno charts are all over Freshalloy.

He runs an off the shelf JWT tune too.

No control over timing or fuel is the usual issue with the JWT (and obviously their selling point too). If you're going with an SAFC to fine-tune fuel you've fixed the smaller half of the problem. You'll still want something to tune timing with which is more important IMO.

That being said, plenty of people have done great things with JWT ECUs.