After sudden loss of et I compared before and after runs and saw a 550 rpm drop in drivshaft speed while on the stop.thinking torque convertor or tranny slipping.Engine rpm and top end mph stayed the same,any thoughts?

I am thinking that if you had a converter issue or transmission slip it would show up primarily under full load.

I had the same thought,but gap between driveline speeds begans to close at full throttle.Can't figure this one out.

post before and after graphs

Rusty,

I don’t think he has run the car since then. Great Bend will probably be his next race but I know he’s wanting to figure this out first.

Possible ground to stop or electrical connection? Just a thought.

Going to Great Bend with rebuilt tranny and converter.When in dought throw $$$ at it!

Possibly the lack of altitude may help fix the problem (Salt Lake down to Great Bend). Good luck, you will find the solution to your problem. This may have simply been an air bleed size problem.

See you in Vegas in November.

Bob

If engine RPM is the same and DS is 550 low, I would next look at G-meter reading.

And when you say 550 low is that at the end of your 2.x seconds on the stop?

Assuming you are shifting on time .5 out it's hard to imagine how trans / converter would be cause that.

Bob I raced in Denver before going to Salt Lake,no problems there.Also 5 passes at SL before problem accured.
Greg as you said shifting at .5 from time stop closes to end of run driveline is slow,gap narrows slightly after stop comes off.I dont have gforce sensor.et off a tenth.Only explanation can be drivetrain slipping I checked for brake drag nothing there.