I bought both manual boost controllers from Donald and decided to show how to install them with an external wastegate.

https://www.homemadeturbo.com/forum/index.php?topic=72836.msg858192#msg858192



The black one is the same as a Turbonetics.
The red one the same as a Turbosmart.

Both are bleeder type valves and should not be used inline with the wastegate.
Bleeding into the atmosphere is also not recommended.
By using a closed-loop system, it will help prevent boost creep and surging with ambient temperature changes.

I found several diagrams for this system, but mspaint always wins:


Here's what I started with:

Pull the cap up to turn, push down to lock.


The arrow shows the air flow.


It only took me about 1.25 turns to change the boost pressure.




Don't forget these guys:


A6/Z6, LS/Vitaras


Ready to go


Intake manifold is the best source. Line goes to side port on wastegate.


Mounted in the engine bay.


Short hoses to mbc/wastegate vs. 2 5ft. hoses from in-cabin.


Open dump of course.


Here's some pics of the other beast:

175/70/13 madness. thin to win

DeluXe


I went from 9psi to 12 psi and it works great.
Next I'll install the motorola map sensor and up the boost/tune.
The red one will be basically the same, but the included T has a ball and spring inside. Stay Tuned for that.

An inline ball and spring mbc is so much easier.

Question/Comments/Concerns?

 

so the closed loop system prevents the surging, i didnt know that. Nice writeup Mike. do the turbosmart pieces look like good copies? let us know the difference when you install those.

 

So does the boost hold solid?

I had so many problems with the MBCs that I tried on my last setup. I tried both the TurboXS and Turbosmart MBC using a number of different configurations but never got the boost to hold like I wanted.

I never used the top port like you did though, maybe I will try that out this next time.

P.S. The real Turbosmart MBC is a combination of ball and spring and bleeder valve. The basic turboxs is just a simple bleeder valve.

 

Wouldn't closed loop be able to hold a given pressure during different air temps?

 

Yes, and that is the best part of closed loop system. It only relies on pressures. A bleed system relies on flow which is effected by temperature.

 

I use a real Turbonetics MBC.

Actually the Turbonetics MBC doesn't have a ball. It uses only a spring and diaphram. The nice thing about is that the diaphram has a vent built into it.


Be careful of some of the knockoff ones. They will have the arrow pointing the wrong direction.

 

And this setup does that? I'm lost.

 

Yes, it simply adds boost pressure to the top of the WG. How ever much you add to the top, you obviously need that much more on the bottom to raise the valve. Only pressures are involved.

A bleed system relies on flow to decrease the pressure to the WG and flow is related to temperature. Ideal Gas Law.

 

I'm having trouble figuring out how this setup works on pressure, while every other boost controller I've played with had issues of boosting different at different temps. We've still got the standard boost controller, and a wastegate with the standard spring in it. However it adjusts the boost, I'm having trouble figuring out how all of this eliminates the different pressures of different temps.

 

Anyone else had sucess with their MBC hooked up like this??