New engine and 4l60e combo, slipping in 4th

[edcmat-l1]

Yes, at idle, not moving, the TCC slip should be same as your idle speed.

1500-1700 @ 5200, part throttle sounds a bit much. The same slip at lower engine speeds under a bit more load that's not surprising at all. It is more of a "feel" thing though. You gotta figure the converter has basically 2200 RPM of slip built into it. If you get max flash out of it from a 1000 RPM idle speed it should go to 3200. So having 15-1700 rpm slip isn't out of hand, depending. At 5200, not at full song, sounds a little excessive but not terrible.

I know you said you had 2 setups, 2 converters from the same company, but even so they can be different. I'd bet they can build 10 different 3200 converters and they would all perform differently, at least slightly.

A big time bracket race buddy of mine years ago would buy 4 or 5 converters all the same stall speed, from different companies and try them all to figure which one works the best for his combo. He actually won a IHRA national championship in the early 90s.

I've posted on here recently about another drag race buddy of mine with a 5500 converter that sounded like it flashed to 7500. The car went down the track 75-7800 rpm and you couldn't hear it shift. Sounded like it went down the track in one gear.

Might be time to drop the pan and see what surprises await you.

[abc]

Thanks for your input ED.
I'm gonna throw this question at Circle D also but, what do you guys think about this test: I'm not sure how much power the TCC clutch will hold but do you think I could lock up the TCC and roll in some power, say start at around 250 to 300 est. and work up to around 450 to 500 and monitor TCC Slip percentage? If the trans is slipping it should show up with the TCC locked hopefully at low power levels? As of today I have tested for slip with the TCC locked at around 200 to 250 HP and all was fine, it didn't show more than a few rpm of slip if I remember correctly. That's one of the tests that gave me a little confidence to start rolling in the power a little more as the tuning progressed.