JohnK944T

My car has what I understand to be a manual boost controler, which I never adjust... The other day while cleaning the car the **** was loose and I did not realize I was turning it.

I removed the panel that holds it and noticed that the hose on the left side was bent at 90 degrees due to the side of the consel.

First, is it possible that this controler is having little impact on my boost? Right now the car read 16 psi at full boost.. The waste gate is stock.

Second, the **** detents out them spins very free. How many turns should it take to adjust 1 psi of boost.

Third, it is impossible to tell which way to turn the know for increased/decreased boost. Can I tell by the vacume lines?

I would like to adjust the boost down and start to get a feel for how this effects car performance. All while not blowing the head.

Thanks,
jk

dmingis

It is possible that the MBC was doing nothing. If I clamp off the wastegate hose, then I get about 16 psi boost. The other factor here is the actual exaust pressure pushing the stock wastegate open, which limits your boost. Do you have chips installed? If not, you probably want to dial back down the boost. If so, I'd check with the chip manufacturer to make sure that you are running a safe amount of boost. I think my autothority chips are supposed to allow you to run about 15 psi on an otherwise stock car.

If you have the stock wastegate, then you probably have the boost signal hose (on the hot side intercooler pipe) that runs to the MBC. The cycling valve is probably disconnected. The second MBC hose goes right to the wastegate. This is how mine is hooked up, and I believe the MBC in this way works in reverse to how it would work if you have a dual port wastegate. With the stock wastegate, when the MBC is fully open, the wastegate should open earlier (less boost). With it fully closed, the boost will be limited by the wastegate spring vs exaust pressure (more boost).

Verify which way is fully open on the **** by blowing thru the MBC. Try running the car that way, my car will only allow about 10 psi at that setting. Then you can dial in the amount of boost that you want.

JohnK944T

Perfect..

I understand what you are saying.. I need to check on the chip. The stock chip was supplied with the car in a little bag. I am assuming that the chip in the car was created by Huntly and matches up with the MAF. Would the wastegate be my limiting factor, considering Huntly MAF, K27DR Turbo, and MBC??? I bought a modified car with the idea I could save on money in the long run. I sure have a lot to learn about it..

Thanks,
jk

Luke

John, you wouldn't be any chance work in Birmingham, would you? Drive an 88, stone grey 951 with GT3 wheels?