2013 Chally RT Whipple 2500 rpm stumble

[Ditosmotors]

2013 Challenger rt auto, 392cid, cams (not sure what kind of cams) whipple 14psi

This vehicle has a stumble at around 2500 rpm and between 47 and 48 mph. It will also do it at the same RPM at around 25mph and the customer says he can get it to stumble the same way at around 3500 rpm . This is with part throttle and is easier to get it to happen when going up a hill. To me if feels like maybe the bypass valve is possibly closing and opening causing the stumble. When I log it, I dont see anything that stands out at me. The map KPA stays around 75kpa and you can see the RPM osilate a little when it happens but other than that I dont really see anything in the log. At this point I'm not sure what to try next. Other than this issue the vehicle drives great. Wot is great, and you can drive through the rpm with more or less throttle and not have a stumble but when you get it just right is will stumble at that rpm.

In the log the the stumble is very hard to see but you can see the RPM fluctuate toward the end of the log between 47 and 48 mph at around 2500 rpm.

[Jay@HAP]

can you post the tune?

[Ditosmotors]

here you go.

[Hemituna]

Often cam timing moving around is the cause.
Log it and see...

[Kmoney]

Whats the spark plug gap?

[FlyinRyan]

I went thru this with a Whipple Durango I did remotely. Everybody kept telling me it was the neural network blah blah. It was a faulty bypass valve.

[Ditosmotors]

Gap is at 28. I wish it was as simple as cam timing. I loged the cam timing and that is steady at that range, no change at all. I have the cam timing set up in all the part throttle maps like i have it in WOT mode.

[FlyinRyan]

Gap is at 28. I wish it was as simple as cam timing. I loged the cam timing and that is steady at that range, no change at all. I have the cam timing set up in all the part throttle maps like i have it in WOT mode.

Have you checked the bypass valve operation? I went through hell trying to figure it out, I would not wish this kind of frustration on any professional calibrator !!!

[Ditosmotors]

I believe that the bypass valve is causing this, but I have to wait for the customer to return sometime next month to try and fix the issue. I will update as soon as I get the car back in my hands.

[Jay@HAP]

I believe that the bypass valve is causing this, but I have to wait for the customer to return sometime next month to try and fix the issue. I will update as soon as I get the car back in my hands.

can you keep the valve open by putting a zip tie or something on it and drive it to see if that eliminates the problem?