Torque Converter Selection - CHP How It Works

Driveline Pros At TCI And Pro Torque Offer Hard-Hitting Insight On Torque Converter Selection & Design.

Stephen Kim Nov 12, 2010 0 Comment(s)
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"At Pro Torque, we rate our converters up to a certain power level. Our current catalog includes converters rated at 500-, 650-, 850-, and 1,000-plus horsepower. At the 500hp mark, features such as anti-ballooning plates, furnace brazing, Torrington bearings, reinforced blades, and billet covers and clutches are used to fortify the converter. As power levels increase, the basic components stay the same, but they're just a little beefier. The converters we make for 3,800hp twin-turbo cars actually have similar features as our converters rated at 650 hp. They might have billet steel stators, but the basic components are the same. This is yet another example of how race technology from our top-of-the-line converters trickles down to our street product line."

Stator Design
Joe Rivera: "Through exhaustive R&D, we've learned that modifying the stator is one of the most effective tools in tuning the characteristics of a torque converter. We can take the same pump and turbine, and completely alter the characteristics of the converter just by changing the stator. This is because how a converter transfers power is determined by how the stator redirects the fluid. Thanks to our billet stator program, we've been able to make huge strides in understanding how different stator designs affect performance. The process starts with a solid chunk of steel, which gets machined down into a stator in our four-axis CNC mill. Last year alone, we made 175 different billet stators designs, all with various blade angles, blade pitches, blade lengths, blade counts, blade shapes, and window sizes. All of these factors affect how oil gets redirected inside the converter. By creating our own stator design while leaving the pump and turbine untouched, we can take a 10.5-inch converter and change stall speed between 3,000 and 5,500 rpm.

"There are always exceptions, but generally speaking, adding the number of blades raises the stall speed while changing the pitch of the blades can lower stall speed. Blade design also affects the multiplication ratio, so stator design can get very complex. Let's say you have five different blade counts with three different blade pitches that you want to test. That's 15 different combinations just based on one blade design. Add blade length and window design to the equation, and the number of possibilities goes up exponentially. As you can see, it takes a lot of time and R&D to design the right stator for an engine combination."

Quality Control
Stanley Poff: "Torque converters are inherently complex due to their multitude of moving parts, and we take extreme measures to ensure quality control. Many of the components are made to specifications with tolerances held to 0.002- to 0.005-inch. Items that are heat-treated have to be within a certain range or hardness in order to have adequate durability. Furthermore, endplay in the torque converter is set so the torque converter has the correct preload on the bearings inside. Each torque converter is air-checked in a water tank under 120 psi of pressure to ensure there are no leaks, and every torque converter TCI produces is balanced to within 5-10 grams on a torque converter balancer. TCI also has quality control engineers that spot-check all of its products including transmissions, torque converters, and shift kits."

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