I have heard about them but I have yet to completely figure out what the deal is with them

 

That is actaully a very good question. A stall converter is one that has a higher stall than stock with the stall being the highest hydraulic slip of the converter before the car must move. Thik of it like a slipping clutch. The proper stall speed depends completely on the power band of your engine. This means that if you have an engine that starts to "pull" at say, 2100 RPM and you have a 1600 stall converter, your performance off of the line will not be at it's best. On the other hand if you put in a 2400 or 3000 stall you will be wasting expensive power, since the converter won't be passing the maximum power to the tranny until later in the power band. In the example I used, a 2000 stall would be ideal since you will "flash" up a little bit on take off. You will then be at the optimum take off RPM. Sometimes too, people have the proper stall converter for the engine combo but have the wrong rear end gears to fully utilize the power.

 

Hey, thanks for asking that question. I was wondering too but didn't have the ***** to ask anyone here. There are no stupid questions just stupid answers.

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1984 Firebird SE
1985 Camaro z28 305 engine T-5 Five Speed Tranny, 92 Camaro Leather Seats Console, carpet everything. Soon to put in 700R4 and 427CI. (Hopefully.
To view my car go to:

http://geocities.com/jmboriss/bluecar.html

 

"stall converter" isn't the proper term since all torque converters will stall. A typical stock converter stalls around 1200 rpm while a better street performance converter is around 2200 rpm.

The stall speed will vary from car to car depending on how much torque the engine produces. A converter that stalls at 2200 rpm behind a SBC could stall at 2500 behind a BBC.

The current converter in my race car is "rated" at 3800 rpm. Because of how much power I produce I'm finding that it's not enough. I need something more in the 4200-4500 range.

The only way to find how much the converter will actually stall is to use a transbrake. The vehicles brakes won't hold the car to the stall point so if you have a 2200 rpm stall converter, you won't be able to use the brakes and bring the engine up to 2200 rpm. Using a transbrake engages first and reverse preventing and output from the tranny. You can then bring the engine rpms all the way up to the stall point. When the transbrake is released, the reverse pressure is dummped and the car launches at the converters stall point. This is like using a manual clutch transmission and launching at a high rpm. It's a drag race component and isn't needed on the street. It has a tendency of breaking stock u-joints and differentials.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block (times are for the current engine)

Best ET on a time slip: 11.447 altitude corrected to 10.99
Best MPH on a time slip: 119.42 altitude corrected to 124.86
Altitude corrected rear wheel HP: 493
Best 60 foot: 1.586

Racing at 3500 feet elevation with a typical race day over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

[This message has been edited by Stephen 87 IROC (edited November 24, 2001).]

 

I got another Q for you guys then.

I've read something from Summit that your stall rating on your TC should be ~500 RPM below peak TQ RPM on your motor (for drag strip purposes). This sounds similar to what Leo was saying about the flash stall thing. Is that right?

I know this is only truly possible if you have your engine dyno-ed, but seems like it would make sense, right?

Thanks,
AJ

 

That would be for strip only since you are going to waste power below that. The way I explained it you get to use all of the 'usable' power band.