toddk911

Doug: you have full 30psi at 3,600rpm? or 15psi at 3,600rpm?

Also, did you build it exaclty as the Audi way and with the same relief and regulatro the use?

sweanders

Are you running 2 Bar boost or 2 Bar absolute pressure? Seeing 1 Bar on the stock gauge is not very impressive. With the stock K26/6 I had 1 Bar boost at 2800 rpm's with a Reliaboost, chips and a shimmed stock WG- even had the stock CV in place and hooked up (after the Reliaboost).

If you run 2 Bar of boost I would be interested to see what other mods you have done except for the stuff in your signature.

As I see it the boost machine could be usefull if you want to increase spoolup time since the ball&spring blocks off the signal to the wastegate completely.

toddk911

In the DIY boost machine they have the relief valve first and then the regulator. But I tried all differnt ways to hook it up and did not get the results others are claiming.

Douglas Sorrells

Sweanders is correct I am referring to 1 Bar on the stock boost guage @ 2700 rpm. The car hit's 20 lbs of boost on my aftermarket PSI guage at about 4000 rpm. The MBC has it limited at 20.

This is the setup I currently have on the car.




I have pretty much listed all mods in my signature.

The relief valve does significantly reduce the spool time. The car will spool normally until the guage reads about 8 lbs, & then flips instantly to 20.

d

toddk911

Are you running the check valve?

I see you are using a different relief valve then the original setup they did. Or is that the regulator? The beige one.

What were your before and after results in spool up?

toddk911

Are the Boost Sciences controlers relief or regulators? I assume the "bleeder" types are considered relief and ball/spring are regulators?

But the ball/spring have a bleeder hole also so would that be a relief/regulator in one?

Douglas Sorrells

The relief valve is on the left, regulator on the right. I currently do not have the check valve in place. Spool up before I installed this setup was very linear. Spool would gradually and steadly increase at consistent pace until max boost was achieved well past 4000 RPM. With the relief valve in place, spool is linear and about the same until about 3600 - 3800 RPMs, & then PSI goes from 8 to 20 instantly. The car will break traction on dry pavement @ 55 mph in 2nd when boost flips to 20 psi. Spool in first and second was greatly improved. It takes a bit more time to spool in 3rd. I'm going to try the check valve again now that system is tight to see effect.

Oddjob

The Boost Sciences controllers (MBCs) are regulators. The accuboost is a ball and spring relief valve.

Typically the accuboost type relief valves should have a small bleeder hole on the down stream side of the valve (this could also be internal to the valve body so it may not be visible on the outside). This does not make it a needle type pressure bleeding valve (that is something different) - the sole purpose of the little hole is to drop the pressure in the WG line after the valve closes. If that hole was not there, when the throttle closes and boost drops, the pressure relief valve would close, but the line to the waste gate would stay pressurized keeping the WG valve open. So the little hole just depressurizes the WG line so the valve/diaphram will close.

The Audi setup is using an off the shelf pressure relief valve that has not been modified with the bleeder hole. Because of this, they use the directional check valve to depressurize the WG line. If you use an accuboost or equivalent pressure relief valve that has been modified for use in a turbo charging application, the bypass line check valve is not needed (unless the pressure regulator has an internal check valve and only allows one directional flow ?).

An 8-20 psi instant jump in boost may be a problem for some drivers/cars/applications. I know that I would not like that kind of instant and unmodulated torque hitting that hard on a track car.

Douglas Sorrells

It is a bit crazy on a street car also, but sure a bunch of fun. It only spools like that under WOT so the car is very drivable under normal driving. Definatly have to take it easy or turn down the spool speed under wet conditions as traction becomes non-existent.

toddk911

"The Boost Sciences controllers (MBCs) are regulators. The accuboost is a ball and spring relief valve. "

Ok, you lost me. Isn't the Accuboost one type of MBC that Boost Sciences sells? Along with the Reliaboost.

Or in the term "MBC" you are referring to thier "black ****" style?

Oddjob

Dont let me confuse you, let Boost Sciences confuse you themselves...

http://www.boostsciences.com/mbc.html

Personally, I would use the term Manual/Mechanical Boost Control for any sort of mechanical valve used to control the WG opening, versus any electronic/computer controlled setup.

But for some reason, both Boost Sciences and Lindsey Racing refer to their "black ****" pressure regulators as MBCs, but do not refer to their Reliaboost/Accuboost and LBE pressure relief valves as a Manual/Mechanical Boost Controller - which technically speaking, they are.

toddk911

So the accuboost/reliaboost would both be considered relief valves?

Oddjob

Yes. The dial adjustment on them just changes the preload on the spring (for the ball and spring). The more tension on the spring, the higher pressure it takes to open it (and pass flow/pressure down to the WG diaphram).

toddk911

Ok cool.

I think JChen,(???) also used this "audi" set up. Although he used his Reliaboost as the relief and then the regulator used in the Audi set up.

J Chen

Hah,
You remembered Toddk. It works great. For those who already
have a Tial wastegate installed, you can obmit the check valve
altogether as top port of the Tial is left to vent to atmo.
One problem I notice as like any mechanical device,set boost does
change with differring temperature conditions.