Not seeing a transmission section so I posted here

Can anyone explain to me why some high stall converters have a dip or drop in RPM’s just after they hit their stall speed and also a pause in acceleration just before continuing to climb the RPM’s and accelerating then cycle ? I’m talking about a WOT take off from a dig while still in first gear. With all things being equal and the stalls being the same, on acceleration from a dead stop, one converter will have the RPM’s climb quickly, stall or grab, then keep climbing and

pulling. The other converter’s RPM’s will climb quickly, grab but pull down the RPM’s and the acceleration will pause, then continue climbing the RPM’s. Even if they stall the same, it seems the second converter slows the car down. Could it be the STR is not proper for the set up? How can this be avoided? I’ve seen this in even 4000 stall converters. I thought high stalls removed dead spots or rpm dips like that. Any info?


I have a converter that I have not installed. Described as 3600 stall. Tighter than normal with high efficiency but lower torque multiplication. I’m hoping it doesn’t do that. I’m Hoping for a smooth transition in coupling not such a hard grab.

 

Not a Transmission Expert by any means. That being said, Neal Chance is a Transmission and Converter expert.
A Friend of mine, Marty Palbykin, was running 6s in the quarter mile, in 1996, with his stuff and a 406 cid Pontiac engine with twin turbos.

Now the Kean Brothers, followed a different approach. They still used quality stuff, BUT, they kept, and paid for, the converters (borrowed from other people's stuff sitting on the shelf in the trailer) to find the converters that worked in their Mustang with their Powerglide trans. It was all track proved parts, either it worked and the Keens bought it or they returned it to the person after a day of track testing.

So my opinion is that either you go to a true expert on converters or do a lot of testing.

Tom Vaught

 

(IMO)

It's the converter coupling. The converter slips / flashes up to XYZ RPM, and then starts to couple pretty hard. The converter is dragging the engine RPM and wheel speed towards one another.