HeavyOlds

I bought a low cost 9.5" 3500 Stall from Redneck performance a few years ago which ended up stalling at 5000. They said my 455 had more torque than expected which caused the higher Stall. I recently became aware of efficiency. This converter produces a ton of torque at the start line but ET could be better and MPH is quite a bit lower. I've calculated 12% slip at the top end of the track. What can a person expect from an efficient 5000 Stall? Is this as good as it will get for such a high Stall converter? I am pulling the transmission tomorrow and thinking of sending the converter off to be tightened up a bit and I'm wondering what to expect for efficiency at lower Stall speeds. My torque peaks at 560@4500 rpm. I want to plug these numbers in to my Drag2000 simulator. What are you guys getting for slippage with your converter? It's a trade off between a good launch and making heat instead of ET.

botmbulb

There is a lot of ET to be had in a good converter, especially with a non standard combination like a high torque Olds. I had an off the shelf JW 10" converter that worked well with my 11.90-12.00 combination. When I built my next combination, it drove through that converter terribly, and ran 11.70-11.80 @ 112 mph. Had Select Performance custom build a converter for it and ran 11.30-11.40 @ 117 mph with no other changes. It's not just the slippage in high gear (which is bad in itself), it's the higher slippage early in the run and on the gear change.

HeavyOlds

Wow. Almost half a second with a more efficient converter. Yes, a loose converter will suck HP all the way down the track. Was it a different Stall speed as well or just more efficient? What are you now running for a Stall speed? I'm estimating maximum torque around 4500 rpm. Should I be running a 4500 rpm Stall converter?

71 delta88guy

Neighbor has a 03 f350 7.3 diesel. Tows a heavy 5th wheel. going up hills gets down to 30 mph-HEAVY camper. Blew up the converter-saved the trans and did simple rebuild with a billet single disc converter. Now takes the same hills at 70.
Yes a diesel but the efficiency of stock,and a LOT of aftermarket converters leaves a LOT to be desired.

TripDeuces

If you are strictly drag racing the car then match your stall to your TQ peak in the RPM band. Any stall higher than that is just being wasted.
From what I've read, Redneck Performance has mostly good reviews but are out of business (maybe?).
When I used to race my Switch Pitch TH400 it had a high stall of approximately 3300 RPM. I used high stall for the launch and manually switched it back to low stall just past the tree using a toggle switch on the dash. Obviously not the ideal setup and a lot of variables to deal with. With consistency in mind I tried just leaving it in high stall for the whole pass. Using it like this resulted in my times being slower by anywhere from 1-2 tenths in the 1/8 mile. Efficiency and high stall should not be used in the same sentence, just doesn't happen.

HeavyOlds

I believe Redneck Performance has re-opened under the name Freak Show Performance. Their pricing looks really good for what they put into their converters. I haven't seen a lot of bad reviews.