Boost leak?

[NeoStreamGSX]

during WOT, my turbo kicks around 3300rpm. boost goes to 18-19psi then drops to 15psi and stays at 15 till redline. what is causing my boost to drop? i have a big 16G ported turbo, with 2.5 o2 dump, 3in exhaust, fuel pump, afc, and ic pipings. can someone help?

 

[candela]

its called SPIKE

 

[NeoStreamGSX]

leak, spike, whateva. question is how do i fix it.

 

[LaserRST]

What type of Boost control are you using? And how is it set up?

 

[NeoStreamGSX]

its a MBC that's a bleeder type.

 

[candela]

If the lines are really long on it, or its leaking it can be a cause...

 

[toshi128]

I have the same problem as well. I have MBC and my car spikes at 18 psi then holds at 15 or 16. The line for my MBC isn't very short too.

What else can be the problem?

 

[RedTurboEclipse]

damn.. i dont have mbc.. my car holds at 15-16 someitmes. other itmes it will start to drop off.. and other times it will spike to 20 psi

 

[NeoStreamGSX]

would an electronic BC fix this?

 

[Bohrn]

does your manual boost controller have a very small hole in the body of it?? If not, drill one.

I made my mbc, and forgot to drill the hole in the body of it, and I got those symptoms. what happens is that the pressure builds up inside the body and will not allow the ball bearing to re seat on the boost side of the unit. A small (1/16th" or smaller) will do it. Too big and you loose signal to the wastegate.

Best of luck.