Looking for some input. I have a 2016 Scat with forged internals and a Gen 3 Whipple (2.9L). Put a smaller pulley on it (went from 3.25" to 2.875") and currently making about 12lbs of boost. I was running the stock Whipple tune with the smaller pulley and the car was running decent.
I took it back to my tuner so he could data log and make some fine tune adjustments for long term driveability. He said it was knocking under partial boost and made some timing adjustments.
Engine seems to be running well and is a rocket under WOT, however, the bypass valve is now surging/fluttering under partial boost, and it has a slight "light switch" throttle with the boost coming on hard at about 75% throttle. It seems right around the point where the pressure goes from vacuum to boost the valve can't decide whether to open or close. Checked the throttle body, and it is maintaining a consistent 25% open (no fluttering with it) under partial throttle.
How are these two things related? I'm not a tuner, but trying figure out how timing (a computer adjustment) can affect the bypass valve (a mechanical part). It was not fluttering at all before the tuner got a hold of it.
Any pointers on what we need to look at to tune the flutter out?
I took it back to my tuner so he could data log and make some fine tune adjustments for long term driveability. He said it was knocking under partial boost and made some timing adjustments.
Engine seems to be running well and is a rocket under WOT, however, the bypass valve is now surging/fluttering under partial boost, and it has a slight "light switch" throttle with the boost coming on hard at about 75% throttle. It seems right around the point where the pressure goes from vacuum to boost the valve can't decide whether to open or close. Checked the throttle body, and it is maintaining a consistent 25% open (no fluttering with it) under partial throttle.
How are these two things related? I'm not a tuner, but trying figure out how timing (a computer adjustment) can affect the bypass valve (a mechanical part). It was not fluttering at all before the tuner got a hold of it.
Any pointers on what we need to look at to tune the flutter out?