2018 Jeep SRT8 GC. I do alot of Mopars and I've not really had major issues tuning the boosted ones for the most part, at least not anytime recently.
Customer is at high elevation. (Denver- so think 6000 ft)
I first tuned this jeep remotely when stock , went great.
Customer then added a TSP custom ground camshaft and MMX Drop Ins- I do a ton of TSP Hemi cams- cam is a 224/237 on a 115 LSA. The cam is locked out and the tune reflects that. NA tuning was a breeze.
Customer then added Fore system, 2.9 Whipple, and Hellcat TB. along with a 18% lower. This is where things have gone afu.......
I have the dreaded part throttle flutter. Anywhere from 1.0 to 1.6 volts or so, throttle/map/pulsewidth all oscillate. this also tends to coincide with 1.0 p-ratio as well.
I have read essentially any and all of the whipple related Hemi threads here, and have implemented most of the changes. I have reduced TB airflow/desired large range to about 60-80 g/s and while the flutter is FAR less severe, and oscillates slower, it is still present. I believe I have gone as far as I can with those changes specifically.
I have also noticed in my log that as rpm/tp increase into "the flutter zone" , once it goes into flutter "Total Airflow" rapidly drops to almost zero.
I have never been one to copy/paste out of other files but I did look into Hemituna's files supplied and did implement some changes that did provide some benefit, but it has not gone away.
As I understand it, if I dial up a higher pedal pct% torque request at the flywheel it will only make the problem worse, bumping into the corresponding tq or airflow limit even harder.
I believe due to the reduced vacuum due to the camshaft, combined with the high elevation, I believe this issue is beyond what can be solved in the calibration, and requires a modified bypass so that it is not so quick to close.
Any suggestions?