Can someone help me out? If I haven't told you already, I'm 17 years old and still learning more and more everyday about cars. The one thing I have never fully understood is stall speed on a torque converter. I know that it is the RPM when the first clutch begins to move the second one (I don't know if its a clutch...I think you know what I mean). Anyways, can someone explain torque converters to me? How they work, and what different stall speeds will do for your car performance-wise. Thanks in advance!!

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"People in cars cause accidents, and accidents in cars cause people"

Justin LaMora

1972 El Camino SS
355 C.I.D. w/450 horsepower

355 Engine (http://www.geocities.com/elky_1972ss/side_engine.jpg)
Interior View (http://www.geocities.com/elky_1972ss/side_interior.JPG)
My Elky at the Sterling Auto Show (http://www.geocities.com/elky_1972ss/show.JPG)

A torque converter is a fluid coupler. It has a portion that is attached to the engine and one to the trans. Between them is the fluid coupling. As the engine side spins, its vanes move or pump trans fluid that causes the trans side to spin and drive the vehicle. Stall speed is the theoretical engine speed that will cause the converter to stall or reach a fluid lock when the trans side of the converter is held stationary. A given convertor can have a different stall speed when used with a different engine. Engine displacement, compression ratio, camshaft timing and torque output all influence stall speed. You should never buy a 2500 rpm converter off-the shelf and expect it to have a 2500 stall speed. Any performance converter should be built to your engine specs and vehicle weight and gearing. For the purpose of drag racing you need a converter that will "flash" (Allow the engine to rev on launch) to an RPM level slightly above the engines torque peak. So if you have a big block with peak torque at say 4000 rpm, you would stage at say 2500 RPM. And at launch the converter would flash the engine to 4500 (this would commonly be called a 4500 RPM stall converter.)Typically 3000 to 3500 stall is just right in a hot street car. I use a 10inch 3000 stall Hughes converter in my own street car and an eight inch 4500 stall in the drag car.