Full boost at 4200 rpms?

[VergeTSi]

I have a 97 GSX. Finally fixed all boost leaks. Holds 20 psi and bleds down to zero in 60 seconds. It pulls alot harder now but it hits full boost at 4200 rpms. I have big 16g, clipped 10 degrees, FMIC, Ic piping, K&N cone air filter, 1G bov, 1G TB, set at 9 psi, 190 FP. I just replaced the fuel filter, it was really really clogged and dirty fuel came out, I don't know if that has anything to do with it. I haven't boosted it yet after the fuel filter. Once i do the dodge mod to the 1G I will be turning it up to 15 psi. Its pretty wierd for it feels kind of sluggish untill 4200 rpms and it puts me in my seat but what I have been hearing from many of other members they are hitting low 3200-3600 rpms with 16 psi. I will be rewiring my fuel pump soon but don't think it can be that, that is causing the high rpms boost. Any ideas? Thanks

 

[Calan]

How evenly does the 20psi bleed down? If it's going from 20 down to 10 or so in 30 seconds, you still have a leak somewhere. Check for an exhaust leak around the manifold also.

If it hits full boost at 4200 rpms, and full boost is only 9 psi, you have some issues methinks

 

[AWD_Hybrid]

I'm pointing the bone at the clipped turbo for the later spool.
The psi bleed, I'm guessing the 1g bov. Evo 7-8 or mr bov
Cheers !

 

[VergeTSi]

The bov help to 20 psi without opening. I had set the psi to 9 untill I fix all the leaks. It bleeds down from 20 psi to 10 psi in about 10 seconds. So theres still a leak? I might have an exhaust leak, I am actually going to seafoam it soon to see if I have any leaks. Can it be the clogged fuel filter? or the fuel pump not being rewired?

 

[VergeTSi]

What about timing? I think I have it set to stock timing.

 

[AWD_Hybrid]

Your mbc is spiking 20 psi for you. You're bleeding off somewhere.
A presure test from the ic hot side hose onwards will show leaks if
you have any after the turbo. Maybe exh mani bolts loose or you
might have reused the mani to turbo gasket & it might be flattened
out in a corner. The mitsu double folded centre gasket can be reused
if you have one of them, but the flat ones are susspect 2nd hand.
Cheers !

 

[VergeTSi]

I did change out the exhaust mani gasket a few months ago and one of the studs kept turning. How do I check for exhaust leaks at the mani? I hate using the stethoscope. For I did another boost leak test and it found a good leak at the throttle body gasket again. Fixed it and it was so quiet that I can hear a pin drop across the street, I heard no leaks, it took a good minute to bled down to zero. Still hitting really high at 4000 rpms. My friend has the same set up and his car hits hard at 3200 rpms. So sounds like an exhaust leak?

 

[AWD_Hybrid]

A stud pulling out of the head could be the cause. You could try spraying
some water at the mani while a mate holds 3k & see if it spits at all.
Cheers !

 

[BoostFrenzy]

If you have found all your boost leaks, then yes it is a pre turbo exhaust leak. So that means there could be a leak at the following areas:
-Head to manifold
-A crack in the manifold
-The manifold to turbo gasket
-The hot side of the turbo is cracked
-Your wastegate flapper is bad or the housing around the flapper is bad

My guess is since you have a stripped exhaust manifold stud, that that is where your leak is. Helicoil it and then it should run fine if that's your only exhaust leak.

 

[VergeTSi]

I'm hoping it's an exhuast leak too. The only way to check for an exhuast leak is sea foam? Would a stethoscope be efficient? Thanks

 

[kraka]

For exhaust leaks around that area, I usually wait till the car has cooled down several hours later, and then start it up and feel around for leaks. You should be able to feel heat coming out, make sure the fans are turned off.