Hi all. Well, I finally worked out some bugs on the charge and hot side of my turbo system. I am getting really good turbo spool etc.
I'm having some difficulty with my wastegate however.
So, my setup is this:
3.4pr Mitsu 16GR6 9^8 turbo External 60mm wastegate When hot, but engine off, the wastegate starts to open at 4 psi, full open by 6 psi. If I hit it in any gear, the boost rises to 6psi or so, then back to about 3-4 then up to 8 , then back to 5, then up to 10 and so on until I am boosting too much for comfort.
In the lower gears the oscillation is faster and the extremes are larger.
The wastegate is sourced from the output of the turbo. Initially I had it off the manifold, but that was even worse.
I blocked the wastegate open and it would not boost at all, so I know my flow is sufficient to control the turbine speed.
Perhaps I need to increase the spring pressure/decrease the opening amount to increase the damping?
I have never done the turbo thing before...looks like I'm still learning. My wastegate has a large opening on the bottom, and a small opening on the side. I figured that you'd want the high pressure exhaust entering on the small side port, and leaving via the large low pressure port. Looks like I was wrong.
I looked at the TIAL website, and they have their manifold hooked up to the bottom of the gate, and exit out the side. In other words, increased exhaust pressure will tend to push the valve open, not closed. This is my issue...I have exhaust backpressure and diaphram operating pressure fighting each other. The manifold pressure eventually wins, but then the turbo pressure backs off, gate closes, repeat....
