Oddjob

The ball and spring is a pressure relief valve (the reliaboost, accuboost, LBE).

The home depot and MBC (boost sciences and the Lindsey one - I think) are pressure regulators.

The "bleeder" is something like a needle valve to be used for flow control. This is a different control valve for a different use than either a press regulator or pres relief. I have a little bleeder/needle valve on a little air compressor for air brushing. You can adjust the amount of air through to the air brush, by bleeding off air flow out of the needle valve.

Since you dont have or want air flow through to the waste gate (unless you have a hole in the diaprham, there is no airflow through it), you are really just pressurizing air in the line to the waste gate, the needle valve/bleeder is not a good or practical valve for a boost control setup. Which is what your posted article touches on.

toddk911

Ok, Jim, thanks for the info on that.

So that rules out "bleeders"

I have tried and am trying again now to new Tial and will see if dual port helps as well.

part one of the article: http://www.autospeed.com/A_0670/cms/article.html
part two: http://www.autospeed.com/cms/A_0685/article.html

think the articles are subscription-only... if so, i can email 'em to you.
mine is very similar, but have been making some changes to it.

i had a reliaboost on it for about a week... was pretty unhappy with it. boost took forever to build, and was far too linear for my tastes. the stock CV, with a restricter in the line was better for me...
now bypassed all together with this manual controller.

"the way it works is like this: http://autospeed.drive.com.au/A_0670/cms/article.html

two valves in-line...

http://autospeed.drive.com.au/cms/A_0685/article.html


first is an adjustable pressure relief valve, which will not let ANY pressure by it until it has reached the point you set. mine doesnt even let anything go past until like 10psi... so NOTHING gets to the wastegate until then.

second is an adjustable pressure regulator. so i can adjust the overall pressure going to the wastegate, after the pressure relief valve starts feeding pressure.

so far, it has been pretty reliable and consistant..."

jimbo1111

I think you missed what I was saying. Anyway. The home depot air compressor regulating valve will work best with a dual port WG. I do not trust the setup on the link you posted. Holding back pressure to the top port will only take pressure off of the spring and prematurely open the WG.

toddk911

So what is the difference from the Home Depot "black ****" and the Boostscienses "black ****"?

toddk911

"Holding back pressure to the top port will only take pressure off of the spring and prematurely open the WG."

What part of that setup do you think would cause this? or do you think the whole set up itself would cause to creep open?

My understanding was the relief was to control creep, inline with the regulator to control total level of boost.

Oddjob

I think they are both pressure regulators, so by function, they are the same. But the boostsciences regulator has an adjustment range of 0-25 psi, and a home depot air compressor type regulator probably has a range of 0-100 or 0-150 psi. Because of that, I would guess that the boost sciences regulator would be more accurate with small differences in adjustment, in the working range that we would want for a 944T application.

Oddjob

The link, describing a setup using a relief valve in line with a regulator, is for an Audi 1.8T application. They are using that setup in front of a stock audi N75 valve, which sounds like something similar to the 944T cycling valve. I also think the the stock Audi waste gate is a single port diaphram arrangement.

I would think the only effect of putting the relief valve in front of the regulator (at a lower opening setting) would be to reduce the boost lag. I dont understand how/why that would eliminate boost creep (using a regulator with a single port WG would allow boost creep) - but I also do not know know the exact function of the Audi N75 valve and how it is controlled (ECU mapping?). So Im really only guessing at this point.

toddk911

Well, it seems many in here are running MBC's AND dual port mode, which I am glad to hear and will try out asap, as I was told only EBC would benifit from dual port .

DLS

Has anyone tried the TurboXS High Performance Boost Controller?
http://www.boostcontroller.com/index.php?category=26

It´s 2 in 1, ball & spring + bleeder

toddk911

Yea, I was looking at all of thier's as well.

I guess a trial and error would be the only way to tell.

sweanders

$242 for a MBC!? Crazy.

toddk911

"$242 for a MBC!? Crazy."

I agree. I KNOW I oculd build an EBC for a lot less.