See here for background: https://www.thirdgen.org/techbb2/sho...hreadid=197892

Test & Tune & Jackpot races today for Mile High Bracket Nationals (summer ET series final). The new converter stalls at 3500 (advertised as 2800-3200) - definately in the power band. I staged at 2900 (throttle up against secondaries), then it would flash up when I released. Comparing some #'s:

Stall.......2200........3500
60'...........2.19........1.99
330........6.053........5.779
1/8.........9.213........8.986
MPH........78.30.......76.49
1000'......11.944.....11.785
1/4.........14.262.....14.165
MPH........97.48.......94.90

I also had a couple of 1.97 60' today, and a couple of 2.00. The numbers for the 2200 stall represent best ever, while typical would be 2.23-up 60', 14.3 - 14.4 @ 96 MPH 1/4's. Obviously, I gave up a couple of miles an hour, but the ET gains were tremendous. It was launching harder today than it was at Topeka last year (2.05-2.09 60'). Trap RPMs were only a couple hundred higher than with the old converter.

This was also the first time I've run the Hoosier Quick Time Pro DOT slicks. They seem to need more burn-out than the ET Drags did.

I think it also really wants more carb now. Proform main body to be ordered soon...

 

Not a bad improvement in ET especially at the 1/8 mile. The loss of mph is expected since the converter will slip more at lower rpms. What rpm do you shift at and what rpm does the engine fall back to after the shift? For a 9" converter, 3500 is a tight converter. I used to have a 10" that stalled at 3800.

Playback tachs are great for watching converter flash. I would stage at 2500 and watch my converter flash to 5300 when I launched. This weekend I get to play with the powerglide and expect a huge improvement in performance. The air is great and I'm hoping for that 10 second time slip. If track conditions are good and I expect them to be, I'm going to try some 5000+ launches.

 

I shift at 5600. With the 750 VS I used to run, it would pull to 5700. Another reason the 750 DP is in order.

The RPMs drop to about 4500 after shifting, I think. I am concentrating on so many other things, I haven't really taken note of that. I'll try to do that today during TTs. Without a doubt, it still is pulling hard.

Another effect of the looser TC: shifts are much softer. With the shift kit and AMSOIL Super Shift (no friction modifiers), the shifts are instantaneous. With the bigger converter, they were also harsh.

Back to TC size: Whether it should be called a 9" or 10" - I need a refresher on that. The case measures just under 10", the Sat. Night Special just under 12", which was about 1" smaller than the stock TC (which I assumed was a 12").

 

The case on my 8" measures 10" also but internally it's an 8". If yours was sold as a 9" then it's a 9" internally.

When you shift, you want the rpms to fall back to around the peak of the torque curve. That's where the stall speed comes in. A high stall speed won't let the rpms fall below the rated stall. When the rpms are lower than the stall, the converter is slipping and performance is reduced. Usually a shift should drop around 2000 rpm.

 

nice ET improvements. your getting real close to the 13s. good job

 

It was sold as a 2800-3200 stall - size wasn't mentioned. I pulled the # from the case measurement, not advertised data. So, not sure exactly what it should be called.

I can buy the part about shifts keeping you at/above the torque peak. But, 2000 RPMs sounds like too much - that should be a function of the gear split, not the converter. Perhaps 2000 is a 'Glide number.

I did watch it today, by the way. It was 4500.

13's at altitude are getting close. Not sure if the carb will do it (probably not), but the cam/intake I've been thinking about might. Maybe next year (unless the air really improves during Fall racing).