C70 Stock Turbo w/MBC Wont Hold Boost

[JxKenny]

1998 C70 HPT
Magnaflow High Floe Muffler
Voodoo MBC
Boost Gauge
Stock ECU

I have a problem. I have my boost set at about 14psi~; at WOT from about 3.2k-4.5Krpm my boost holds at 14psi, after that rpm range my boost will slowly drop off, going to 13, 12 psi... why? Its a TD04 turbo, it should be able to hold 14psi at any rpm, why is my boost fading/ not holding at 14psi, and suggestions?

[madspeed50]

Clogged cat?

Yep, sent from my rooted, rommed Galaxy Nexus....

[RobTheModd]

Hmmm your running 14psi on a stock turbo, with stock pipes, stock couplers, and a stock tune...

Id get that looked at first.




Check your couplers, usually this will happen when you have a hole that is opening up at 14psi (in your case)
The usual suspect when we begin tuning our 850+ models is the Throttle body hose. It usually tears due to age and stress at the IAC air hose that branches off.
Easy to test, feel under neath it at the connection. it should be smooth.
If you like to visually inspect things, its a flat head screw driver clamp. so just pop the one off at the throttle body, the pipe going to it, and the iac hose.

Report back, you could also have torn your cbv.