BEV@GSCMotorsports

Hey, i'm hoping someone can help me out...I have a LS/Vtec setup with forged bottom end, tubular stainless steel manifold, Garret T3 turbo, 3in Down pipe, Tial 35mm, Greddy intercooler and Type S BOV. and my boost spikes out at 12psi and as my rpm's go up my boost goes back down, and levels out at like 4psi... does any one have an idea of what could cause this? Could it be my manual boost controller, setup of the wastegate?



Modified by CivicTurbo12 at 3:38 AM 4/26/2003

r4adkshn1

what kind of MBC?

HRTuning

Do you have a 4psi spring in your wastegate? If so, then it's probably the MBC, once it's opened it isn't shutting while boost continues allowing the boost to be reduced to the pressure of the spring in your wastegate... if not, I would suggest checking the flow charts on the turbo you are running, you may be moving too much air for it exceeding it's flow rating and causing it to drop off at higher revs...

BEV@GSCMotorsports

It's a home made MBC, you think the spring is to stiff?

Snafu-Si

I had boost spikes about 2 weeks ago. Turned out it was my boost controller (profec B). had to change teh settings to overboost.

Is there a way to bypass your boost controller so that you are just running the WG by itself?

BEV@GSCMotorsports

yeah i can, but then i'm only boosting like 8-9 PSI w/out the boost controller, but it still leaks sometimes then too.


Modified by CivicTurbo12 at 10:08 PM 4/27/2003


Modified by CivicTurbo12 at 10:09 PM 4/27/2003

Snafu-Si

crap, well, if you unhooked your boost controller, and it's still boosting, then it is difinetly your WG, or something related to it. Check your lines to your WG, maybe the lower line has a clog in it or a leak that's leaking pressure to open the valve. I'm not to sure what I just said, it' sjust something somebody else said to me when I had the same problem.

If you want to know more, do a search, and do one on topics in the ForceINduciton forums created by me, Snafu-SI, it should show some pages of me askign about my boost spiking problems, you might find the answer in there.

BEV@GSCMotorsports

of course it's still boosting there's nothing to open the wastegate if everthing is unhooked, but running just the wastegate i can only boost like 8-9psi then it drops back down to like 4-5 as my RPM's go up how ever my power band on the dyno goes up and plateus and stays straight accross the board until like 7500

BoostedsiR

as your rpm's go up and you only get 4lbs from that wastegate check the lines going to you boost controller and make sure you try to take off the bc for a day and run at the 4lbs and see if you ride good it will only be 4 lbs and then if your are getting any real hard sputters or loss in power in could be a fuel cut you probably have a fmu... hondata is **** when you get it tuned

BEV@GSCMotorsports

ok well here's the deal... i'm running the VAFC hack (450injectors, walboro 255 pump, Vafc) no FMU or anything... when i take the BC out i can boost 8-9psi then it drops bown to apx 4-5 and when i have the boost controller hooked up it boost like 11-12 psi then drop back down to like 4-5psi....

BoostedsiR, i see you're from Beaufort... I'm from Hilton Head, i'm in collage in PA... IM me sometime Civicturbo12 (Bêv)

spacetuna

You could be losing pressure if your blow off valve is too lose.