You can talk the talk, but do you really know how torque converters work? Allan Blithe explains

One of the most important components in an automatic gearbox-equipped car is the torque converter. It’s often one of the first things changed but, alas, one of the least understood. That’s probably because it’s a steel donut that you can’t easily see inside or pull to bits to gain an appreciation of what makes it tick.

Everyone has heard of high-stall converters but a lot of people have no real idea how they work, what makes them a high-stall or even how to effectively check the stall speed in the first place.

If you have a car that has had the engine upgraded and is making noticeably more power than stock, and perhaps you’re taking it to the drag strip, it might be time to start thinking that the stock converter isn’t up to the job. You will most likely be told you need a high-stall converter, and if you’re in the above situation, there’s a high chance that is correct.

Ideally your converter should be set up so that the stall speed is pretty close to the rpm at which your engine makes maximum torque. This will give you the greatest initial acceleration and, if you’re drag racing, that is important, which is why drag cars use high-stall converters.

Before we dig too far into the high-stall part of it we need to have a basic understanding of the components that make up a converter and their functions.

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