suganuma

I just took my newly put back together car to the track on saturday which left me with a couple of problems - want to check and see what y'all think.

I am using a profec B for boost control and set it up for 12-13psi on low setting and 15 on high with the wastegate letting 9 by with the profec off.
I did these settings while getting tuned in going up to 6500 rpm or so.
BUT...the next day I was out driving the car and noticed that above 7000rpm i am getting boost creep. on the lowest setting of the profec simply turned off i am going from 9psi to about 12 in 3rd or 4th gear taking the car to 7500 or 8k rpm. but when in lower gears i see peaks of 17 psi...boost builds quickly as the tires just kinda spin in the lower gears.

I am using an HKS manifold, HKS standard wastegate, Turbonetics T61 1.15 exhaust a/r, on a street ported FD.

anything i can do to fix this besides buying the largest wastegate possible....?? are other people having problems with boost creep on this manifold and wastegate or other similar applications?? - i dont recall hearing about it.

Other problems is that i noticed oil spitting out of the BOV which i have positioned between the turbo outlet and IC inlet. I was told this might be due to the fact that I am not running a restrictor in my oil feed line.

I guess thats about it....let me know what y'all think

TIA,

mako

iTrader: (5)

I had the same problem with boost creep like you say above on the hks standard wastegate.

I know some 2nd gen guys running them without a problem, but I get a lot of creep in any gear other than 1st around 6500 rpm.

I think for a large ported motor with a decent size turbo the outlet of the standard just cant flow enough air.

jspecracer7

What size is the HKS standard? Isn't it pretty small? I would suggest getting an HKS racing...I can't remember the size of my wastegate, but with my setup(Turbonetics 62-1 with divided a/r 1.0 exhaust) and I don't get any boost creep.

suganuma

HKS standard is certain size.....not a selection between a few

racing one is bigger, but it has a diff flange than the standard one......anyone welded with the cast manifold before??

mako

iTrader: (5)

standard is a 40mm, the racing is a 50mm. I think a big factor is the size of the dump tube outlet on the wastegates, the racing is much larger than the standard.

the hks racing wastegate will mount up to the cast manifold without any modification. Unles you buy the ss racing which has a square base. The problem is the hks racing wastegates are really expensive.

suganuma

how does that work if the valve is that much bigger and it still mounts on the same flange??

i thought for sure that the flange would have to be different to house the bigger piston. and i also thought that the SS manifold was the only one that came standard with the flange for the Racing wastegate

i can see from pics that the dump outlet is bigger, but i just concerned with having to modify the flange off of the manifold b/c i am lazy and it looks like a bitch on the cast manifold.

thanks,

Nic

scott(pittsburgh)

i have the same prob with my T-78 and greddy wastegate..
with the silencer in my N-1,i don't get any creep, with out the silencer in, i get la solid 13psi until 5500 rpms, the creeps to 15-16psi, dunno, maybe the wastegate size?

suganuma

double post

suganuma

i ordered a racing wastegate.....i guess we will find out soon

scott(pittsburgh)

let me know if that helps..