Torque converters are magic. Somehow, horsepower and torque come from the engine, go through the transmission, and the torque converter just magically converts them to tire smoke. Nobody really knows how or where they come from – they just appear out of a mystical cloud of burnout dust…
Okay, that’s not true at all. There are, however, many misconceptions about what torque converters do or don’t do, and what they’re capable of. It seems there aren’t too many people out there who can explain just how they work.
Although, we have found a very knowledgable group who know all about torque converters and their mystical powers. The mad scientists over at Hughes Performance seem to have cracked the code to the whole fluid-coupling mystery.
That’s not to say fluid dynamics, and torque converter engineering is a simple matter. But, luckily for us, they’ve put together a series of informative videos explaining the finer points of everything torquey. The seven-part video series kicks off with the aptly named, “Torque Converters 101: A General Overview.”
The 20-minute video features Pete Nichols who walks us through torque converter construction, the purpose behind the components, and some basic operating theory.
From the pump seal to the cover that bolts to the engine, Pete covers every component that makes up a torque converter and explains its function in a clear and concise way.
Moving on to theory, Pete again puts a complicated function into layman’s terms. “You have a driven pump – the impeller, providing a fluid drive to the turbine.” Pete then goes on to explain torque multiplication and K-factor. However, he does note that while K-factor is common in the OEM realm, it is less common to hear in the performance aftermarket. Thus, it is not a great measuring stick.
Pete expounds on the theory even further. Basically, the engine-driven portion of the converter (pump) takes the amount of torque the engine is creating and multiplies it up to the point of stall speed in the converter. Most converters do so at a rate of 1.2 to 1.8x the ability of torque multiplication of what the engine is generating.
“This is why a car equipped with a torque converter has really great acceleration characteristics. When you’re dealing with a manual transmission and a clutch, you’re relying solely on the multiplication from gear ratio – you don’t have a hydraulic device multiplying torque for you. That’s why you’ll see an automatic car running the front half of the track quicker than a clutch car can in a drag racing environment. That’s not a rule – but we do see improvements with converters and automatics.”
Pete also touches on torque converter slippage, efficiency, and loss of drive between the impeller and the turbine. However, he also explains the importance of knowing what your combination needs for optimum efficiency. “Having the lowest possible slippage number isn’t always what’s best for your racecar or your max-effort street/strip car.”
If you’d like to discuss anything mentioned above, or in the video, such as torque output, horsepower output, rpm capability, weight, gear ratio, tire size, and what your expectations are for your combination to perform, call the professionals at Hughes Performance. Check out their website, here.