98hx99b18c

I cant seem to hold boost in any gear. Im making full boost at around 4k and after that it just drops off, from about 7lbs to about 4.5-5psi. I checked all my IC piping, bov...what else could it be? Leaking intercooler? It sees full boost for about half a second and drops off right after that.

immortal

exhaust manifold gasket ?

JM Performance

what kit are you running? also, external or internal wastegate?

98hx99b18c

I dont believe its the exhaust manifold gasket. I just took off the exh manifold, didnt notice any leaks off the head either, gasket looked good as well. Also its a custom kit...max rev mani, tial w/g, greddy bov, starion IC, custom dp. I dont hear any exh leaks. Only thing I think it could be is the IC, any other thoughts? TIA.

Rob03Pro5

Tell us how you did all your vacuum lines.

98hx99b18c

Ok bov and boost gauge vacuum teed off at the fpr vacuum line. For the wastegate pics are here...https://honda-tech.com/zerothread?id=70938&page=1

Basically line running from the turbo inlet to the side port of the tial, the other end which is closed of in the picture, now has a line running to a turbonetics MBC. The vacuum for the MBC is hooked to the top port on the tial gate. The thing is I never noticed it leaking boost before problem seems to have come about recently. Also hondata on board.


[Modified by 98hx99b18c, 7:57 PM 11/15/2001]

Doodoo

Sounds like a plumbing leak. Either exhaust or intake. I had one on my wastegate elbow and couldn't hear it. Saw the soot though.
Or could be the MBC...
How is your idle? I noticed on my friends car had a hose blow off and his idle went to the crapper.

98hx99b18c

Hmm, I dunno double checked all the plumbing again, nothing. Idle is fine, vacuum right around 20hg/in. at idle. Runs strong, just cant hold no boost.

VTC_CiViC

I had similar problems, turned out to be my MBC, twas a peice of crap.

Rob03Pro5

Try taking off the MBC and just run a vac from the turbo to the side of the wastegate.. leaving the top of the wastegate open. If this works, then it's your MBC.

98hx99b18c

Ok thanks guys thats what Im going to do, what would cause the MBC to leak boost?

Rob03Pro5

poor construction.. isn't Turbonetic's MBC plastic? I forget.. but ya, a poorly built MBC will do that.