I am seeing about 700-800 slip rpm in 3rd at WOT up to about 5k. This is as seen is datamaster, so I am not sure what they use to calculate slip. Around 5k, the slip rpm jumps to about 2000 or so, then shifts, and then it goes back down. Is this normal? BTW, I cross-checked my finish-line rpm (A4/3.23 stock tire sizes) and I am logging 5000 rpm at 100 mph, where the gear calculator is showing 4200 rpm. That cooresponds to the 800rpm slip Im logging, but is it tranny or converter??? The car has 66k on it, the stall about 10k. Fluids look good.
BTW, I looked at logs from past dragstrip passes and see the same pattern. Even with a stock stall the car was seeing 200-300slip rpm in 3rd gear WOT.
Could this coorespond to the slightly lower mph for my times and more importantly, the drop off in the 1/4 performance vs 1/8 (I post in the drag forum about that)? Thanks in advance

 

Whos converter are you using? This sounds like a very inefficient converter.

Frank
CPT

 

I agree with Frank. On my bracket car, I see ~4% (300 rpm with engine at 7,100, 5,000 stall). What is the stall on that converter? The only way what you are seeing could be right is if 5,000 is near the stall speed.

Rich

 

I'll be the first to admit its an offbrand converter (Xtreme 9.5 inch 3k stall). Would I still see some slippage with a stock stall though? What kind of numbers are normal? I dont have anything to compare my numbers with. Thanks Frank.

 

The "slip pattern" in the graphs were the same as they were with the stock stall. Thats is, the graph went up after 5k. Sorry but its hard to explain.