TommyV

My setup is a 94 Civic CX Hatch with a D16Z6, Greddy kit, custom intercooler and Type S BOV.

Before the IC, I was boosting about 7 -7 1/2 PSI with 195-65-15s (yes I know the wrong size tire) since then I threw on the 13s and had the IC installed, and all the sudden I was only boosting like 6 1/2 PSI, well I figured the pressure had to be turned up a little to compensate for the extra piping and the I/C etc. So adjusted the internal wastegate just two turns and I was back to 7 1/2. Just last week I threw on the 15s again, this time with minty dunlop sport 9000s 195-50-15s and WTF, now I'm only boosting to around 7 PSI.
Can anyone explain?

TommyV

Anyone, anyone??

vtec.dc2

tire size can change gear ratio, i guess gear ratio could affect boost..

turbod16y8

check for leaks.... i dont think tires size can do that.

EFIGUY

The size of the tire will essentailly change the car's overall gear ratio, and therefore the way the engine gets loaded for any given RPM in any gear......turbo's use engine load and not RPM to spool, so the change in tire size can affect boost. Now, having said that, it is normally not the case becase most boost controller's are fast enough to respond to the change in loading.....but who knows what can happen in real life.

-Ben

avividmemory

I'm gonna guess the drop in pressure is due to the intercooler...they tend to lose a little pressure which is why you connect the wastegate to a manifold rather than the turbo, so it reads pressure after the drop from the intercooler...

just a guess though...thats all that came to mind

TommyV

Wow, thank you guys for the Great information, I love Honda-Tech!!!

I'm gonna tighten up the wastegate a 1/2 to 1 full turn

BoosT is crazy!!!!!!!!!!!!!!!!!!!!!! I'm hook'd solid!