VNT control

[OM617]

I use a wastegate actuator and opposing vacuum actuator. Ignore the big valve on the upper left, its long gone.





The stock Mercedes automatic transmission Vacuum Control Valve varies the vacuum pressure according to load (throttle position). That reduces the boost PSI it takes to make the wastegate actuator move and limits the overall boost pressure to whats needed.


Its nowhere near as simple as plugging the EGR's tube onto an actuator. To make a VNT work on a non-stock application you need good fabrication skills and to think logically.

[dillenger1]

Why cant you fix a cable to your gas pedal?A stiff one with some return springs,as well as a actuator to work with the pressure.

[OM617]

Search. Its been done before.

I used variable vacuum because my application already had it in place and it was easier to adapt than a cable.

[ahto42]

I know that vacum/no vacum is bad. I studied that in idle mode and cruise is good when vanes are open, i have to find a valve like your mercedes has, but controlled electronically. Does anybody know where to find one?

[OM617]

The N75 valve used on VW TDIs.

You will have to build and program a computer to control it and feed it with throttle position, boost and RPM sensors.

[ahto42]

i was thinking witch is controlled like a gas pedal(in my language potensomeeter)

[ahto42]

n75 is a good thing, how much voltage needs the n75?

[ahto42]

i think i make it so:


replace MAP with TPS,
vacum thru EGR solenoid, adding a relay that cuts vacum when cruising(the signal comes from EGR harnes)