mbc question

[heater]

i have a 98 gsx and just put a turbo xs single stage mbc on last weekend and have a problem. when i turn it all the way down i hold 10 psi, when i put 3-5 turns on it i hold 14 psi and drop to 10-12 at high rpm's however anything past 5 turns on the mbc i spike and hold 14 psi all the way to red line???? so i can not ever get past 14 psi?? checked to see if anything was leaking but found nothing so far.

 

[hystericfox]

It might be easier to tell if you filled out your mod list.

 

[daren_p]

Ya, mod list would help alot. If your still running the stock 2g bov, that could be your problem as it starts to leak @ 12 psi or so. I have the turboXS high performance mbc and can make 20 psi with only a few turns, so what are your mods & how have you got it connected?

 

[oldman]

checked to see if anything was leaking but found nothing so far.

How exactly did you do that? Make sure it was a real boost leak test or you could overspun the turbo. What you're describing is pretty much expected from the stock 2g bov and the t25 except for some minor details which I think may be boost leak related.

 

[heater]

my mods are only k&n short ram, mbc, boost gauge, a/f gauge and a 16g still in the box due to waiting on gaskets.

 

[dsm_eclipse]

the boost drops at higher rpms because when it hits full boost its spikes first and then u hold what ur boost is really at

 

[Defiant]

when i turn it all the way down i hold 10 psi,

Oddly enough, you have something installed incorrectly. All the way down should blow your engine by disabling the wastegate. Search any of the elebenty bazillion prior MBC installation threads.

 

[daren_p]

my mods are only k&n short ram, mbc, boost gauge, a/f gauge and a 16g still in the box due to waiting on gaskets.

I would suspect the stock 2g bov first, as I said before it leaks at anything above 12 psi or so. After that check how you've got the mbc installed & check the intake for leaks. I made 20 psi on my stock t25 (adjusted the mbc too much) so the t25 can make more then 14 psi. I ran 15.5 - 16 psi all the time before I upgraded.