boost controller

[Kracka]

Joe P. is a great MBC, I used mine for years with zero problems.

[Goat Blower]

It's the one I bought from QPR a couple years back. It came off of Mike's car. And it's currently busted. Doesnt hold boost at all. (bad spring?)


Sorry, but that's funny. It must have been his super secret boost controller that he engineered from unobtainium. :D

[turboDSM]

http://img197.imageshack.us/img197/4315/boostlinerouting749714wn7.jpg (http://imageshack.us)

[Kracka]

^That routing leads to boost spike.

[turbo2086]

^ He is right. To receive minimal boost spike, you should have the boost source coming from as close to the turbo as possible.

Ex. Using the little nipple on the stock 1g j pipe.

[Kracka]

I ran up to 25 psi with the MBC coming off the turbo outlet elbow and it was rock-solid with no issues.

[scheides]

What kind of pressure effects??

With any gas, temperature and pressure directly affect each other. By changing the temperature, you can change the pressure, and vice versa. Air in the intake manifold should always be the same, unless your intercooler is getting heat soaked. Therefore, your mbc will always have the same pressure for reference when trying to displace the ball/spring combo for a set boost pressure.

When you run the MBC sourced from an inlet pipe before the intercooler, there will different temperatures of air coming out of the turbo and your MBC will theoretically have it's ball/spring displaced as different volumes of air pass through it (since it is a pressure-based switch). This would result in different resulting pressures in the manifold (after the intake charge has passed through the intercooler).

With that being said, a lot of people run their MBC sourced from the turbo outlet w/ little or no variance in resulting boost pressure. :)

PV=nRT ;)

ref: http://en.wikipedia.org/wiki/Gas_Laws