high boost
 

Hello all, im in a little predicament. I finally got to do a WOT run on my rebuilt engine and noticed the boost gauge shot up to 15psi (couldve been more not sure though) Me and a couple buddies recently changed secondary injectors prior to this. Here's a rundown of the car

JDM 13bt rebuilt with large streetport
255lph Walbro
stock primary inj., 75lb secondary inj.
aftermarket FPR
custom 3" TID with HKS filter
stock S5 JDM turbo with external wastegate mated to the exh mani.
3" turbo back exh.
removed rats nest
Greddy Type S bov

could there be a hose loose somewhere? id appreciate all the help i can get :o11:

It's most likely a combination of the port and the exhaust. Even bone-stock cars with open exhaust will experience a rise in boost pressure, that's why something to control the fuel with is highly recommended even with only bolt-ons.

What boost was it running before all of this? Is this the first WOT run with the new turbo/manifold/wastegate setup? I'm betting that the spring is not right in the WG. With an open exhaust, and the port you have that engine will produce a decent amount of boost. 15psi is way to much on a stock S5 turbo though - so I'd avoid WOT runs until you figure this out...

Werd, I ran a S4 Turbo with boost creeping into the 15-19psi range. Cracked a seal rather quickly.

well before the rebuild it was shooting the stock boost, 6psi i believe.

how would you suggest i get to the spring and check it out? would that even be possible with it still on the car?

HA - yea, I had a stock turbo give up at 11psi!


As for the WG adjustment, you said it was an external WG, so I'd say you should be able to access the spring with the WG in the car, but I dont know your setup. External WG have springs that control when they open, and ultimately controlling what boost you can run. It sounds like you need to swap the springs out for one that suits your needs.

What WG do you have?

well the previous owner put in this setup, but it looks to be an hks style. i checked the hose that comes from the front of the turbo to a hard vacuum line then back to a thicker hose to the wastegate.

PROBLEM RESOLVED!!!!

Turns out that the line to the wastegate was pinched under the UIM so im now im boosting normally WOT