Higher Stall TC???
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Joined: Oct 2005
Posts: 1,847
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From: Sandwich, IL
1). Higher RPM stall speed.
2). Higher STR.
3). Higher shift extension.
What does all that mean for a street car? The stock stall is an 1800 rpm converter. The LS1 motor makes more power at 4000 rpm's then it does at 2000. So a higher stall speed will put you in your powerband right off the bat rather then the stock stall with starts you under it and forces you to climb into the powerband.
The stock STR (stall torque ratio) is 1.6 which is considered very mild or soft hitting. The higher the number the more torque multiplication and thus the harder the car will launch. Numbers are generally between 2.0 and 2.7 for aftermarket converters. For cars that see a lot of track time and have sticky tires the higher STR's mean lower 60' and better ET's. But for street only or street mostly cars you want a smaller STR so you don't fry your street tires as badly. Also a smaller STR is a more efficient converter meaning it eats less HP through the drivetrain.
Aftermarket converters also raise the shift extension which is what rpm the converter drops to after a shift. Most higher stalls have a 4500+ shift extension. This allows you to stay in the LS1 powerband from start to finish. Many people like myself have gained 1-2 MPH in trap speed when they changed to a bigger stall. This is one of the reasons why.
Now what stall is good for you? For a bolt on street car I would say either the Yank SS3200 or the Yank SS3600. The SS3600 is a better performer and has a higher STR for harder hitting launches. I recommend this one for any street/strip car. But if you are 100% street and street tire only then the 2.5 STR of the SS3600 might make launching a challenge. The SS3200 with the lower STR might be better suited for that car.
Hope this helped and good luck.
Last edited by darrensls1; Dec 9, 2007 at 05:58 PM.
