Yes, more wastegate questions....

[PanzerSD]

First off, I apologize for asking so many questions....

but...

Is the wastegate hose a pressure hose or vacuum type hose? Is the pressure (if it is) in that hose the same as what would read on a Boost guage?

if I put an adjustable restriction in-line of that hose would I be able to adjust the boost capability of the Turbocharger without having to adjust the wastegate?

[bgkast]

Yes, I believe that is the case. A manual boost controller is basically just an adjustable restriction.

From hackaday.com: "A manual boost controller is placed in the path of the waste-gate's sensor. The controller bleeds off some of the pressure in the line so that the pressure measured at the waste gate is lower than actual. This tricks the waste gate into staying closed longer than usual so a higher level of boost is reached."

This way you can adjust the boost with out cracking open the waste gate, and can go back to stock by removing the boost controller.

No real reason to bump up boost unless you have bumped up fuel as well, and have some way to control and monitor EGTs.

[dannym]

Wastegate=pressure.

The turbo system works off exhaust gas. It's not vacuum related.

Danny

Originally Posted by bgkast

Yes, I believe that is the case. A manual boost controller is basically just an adjustable restriction.

From hackaday.com: "A manual boost controller is placed in the path of the waste-gate's sensor. The controller bleeds off some of the pressure in the line so that the pressure measured at the waste gate is lower than actual. This tricks the waste gate into staying closed longer than usual so a higher level of boost is reached."

Those types are junk. Go with ball and spring type boost controllers. Search fleaBay, lots of them for $10-25

[sixto]

Originally Posted by Got_The_Benz

Is the wastegate hose a pressure hose or vacuum type hose?

MB didn't use vacuum wastegate actuators in US cars before the 1990 300D 2.5 and 1992 300SD.

Originally Posted by Got_The_Benz

Is the pressure (if it is) in that hose the same as what would read on a Boost guage?

In steady state the boost readings will be the same. The boost signal to the wastegate is right at the compressor outlet whereas typically a boost gauge is hooked up just ahead of or just after the overboost switchover valve. The distance between those two points and that huge chamber in between that is the intake manifold will introduce some lag in the downstream signal. You're probably more interested in manifold pressure than compressor outlet pressure. In fact you're probably most interested in what the ALDA sees since in a sense that's the only usable boost.

Originally Posted by Got_The_Benz

if I put an adjustable restriction in-line of that hose would I be able to adjust the boost capability of the Turbocharger without having to adjust the wastegate?

A restriction will increase the time it takes for the wastegate to open but it won't change the point at which the wastegate if fully open. The big downside is that since the wastegate can't respond quickly to compressor output, you risk interim boost spikes. Under hard acceleration you might see 16psi before the wastegate opens to limit boost to 12psi, vs in factory form the wastegate creeps open at something like 5psi and is fully open by 12psi. I pulled these pressure numbers out of the air. I don't know what the numbers are for your car.

You have much tighter control and predictable behavior with a ball and spring boost controler like ForcedInduction recommends.

Sixto
93 300SD