How to tune a wastegate

V-Ref · Aug 30, 2011

907DAVE said:
I have tried running the boost reference to the bottom of the gate with a heavy spring in my setup, and it does not work well. You have little control over the gate because how fast and far it opens. Recently I loosened the preload (using the same spring) and used the top port on the gate with much better results. I get a touch more smoke on a snap throttle, but once boost rises its much more responsive.

Hmmm. Are the ports on this gate plumbed via reg boost/atmosphere or the reg boost/unreg boost method on this gate? What is the gates spring range of psi (with varying preload it sounds like there's a range of operation)?

V-Ref · Aug 30, 2011

I remember reading a thread or two a while back and folks made mention to logging duty cycle on their WG....

What's the hardware/software solution to enable that?

Drive Pressure seems to be only one side of this, as I feel a bit blind without a turbo rpm gauge and knowing the true duty cycle of the gate if you're to truly tune the gate/turbo system...........if you relate those two parameters to our HPOP system (engine rpm/IPR DC), it'll make sense, as there are some close parallels in my mind....

More money into the money pit!

907DAVE · Aug 30, 2011

V-Ref said:
Hmmm. Are the ports on this gate plumbed via reg boost/atmosphere or the reg boost/unreg boost method on this gate? What is the gates spring range of psi (with varying preload it sounds like there's a range of operation)?

It was regulated boost to the lower half of the gate (as directed by TN), and I had a 18lb spring in there - the stiffest spring they offer. I also was told the adjustment screw was only there to limit how far the gate opens and NOT for adjusting preload....I did not buy into that.

FWIW, I had the regulator almost completely shut to build any kind of boost - crack it open just a touch and it would not pick up more than 30PSI....LOL

Charles · Aug 31, 2011

a_moore said:
Why can a simple pneumatic cylinder not be used to make the tuning a little easier.

If you want slightly more backpressure hook the boost up to the rod side (as it has a smaller surface area on the piston based on rod diameter) and the backpressure to the piston side (assuming that you set it up with the cylinder and gate normally closed). Wala, a self regulated gate control. It may be necessary to add regulator to the air, or say a 20 psi check valve to get things lit.

This (in my head anyway) would regulate itself to near optimal p/r and keep the controls and extra tuning and adjustments out of the equation. As anyone knows who has played with turbos....they run good and pull hard to a certian point, then they start to fall off in power as they are pushed out of theit map and start to create hot boost and high parasitic loss via backpressure.

I will try it someday.

A dual port wastegate is a pneumatic cylinder... with a spring loaded shaft bias and a valve on the end of the shaft. This is precisely why I run very little spring pressure and then control the shaft movement by applying the air to the top to hold the gate shut, then as my duty cycle increases the 4 port solenoid progressively applies more and more air to the bottom and less and less to the top until the desired boost is acheived or the gate is maxed out open.