FAQ's About TCI® Circlematic™

Why should I switch to an automatic transmission set-up?

Cost: A good four-speed runs from $1,000 to $1,200, not including the maintenance of the clutch. A TCI® automatic transmission usually runs $300 to $500 less for a basic set-up.

Weight: Most of our racers have found that the automatic is 50 to 60 pounds lighter than a standard four-speed. The weight savings alone reduces wear and tear on the engine
and drivetrain.

Performance: TCI® automatic transmission performance is outstanding. Several of our racers who made the switch to automatic have been surprised as their cars are more responsive off the turns and quicker to rpm with excellent throttle response in the corners and on restarts. In addition, the TCI® automatic is consistent for every race, so you don’t have to adjust the clutch before each event.

How does the TCI® Circlematic™ Powerglide Transmission work?

Actually, we offer two types of Circlematic™ Transmissions: the clutch pedal style (TCI® Part #742011) and the latest “clutchless” style (TCI® Part #742010). The clutch pedal style works similar to a standard shift transmission. Using a clutch pedal arrangement, the driver’s hands are free to work the shifter and steering wheel. To take off, you simply depress the clutch pedal, select the desired gear, and slowly release the clutch pedal while feathering the throttle. Unlike driving a manual shift transmission, once the vehicle is underway you may shift from low to high or from high to low without depressing the clutch pedal. The “clutchless” style works similar to a Powerglide with a working torque converter. It is very simple to install because the shifter is the only external control required. To take off, you simply put the transmission in low gear and slowly depress the throttle. Once you're moving, you can shift to high gear even at wide-open throttle! Reverse works the same way as low gear, and because it's a reverse shift pattern, there's no chance of bumping the shifter into neutral or reverse during upshifts. This transmission cannot be run in low gear. The TCI® Powerglide Circlematic™ “Clutchless” Transmission (TCI® Part #742020) is perfect for racing where the rules limit rear end gear ratio choice and can be raced in low gear. Featuring a 1.82:1 ratio low gear, the lock-up drive gear is designed for reliable and easy operation. Best of all, the TCI® Circlematic™ “Clutchless” Transmissions have no external hook-ups, lines or linkage, avoiding any chance of transmission leakage or need for component fabrication.

What is the best thing that can be done to keep a transmission working at optimum performance?

Regular fluid changes. We recommend changing fluid at least every 150-200 laps. TCI® offers two types of fluid: Max Shift™ Racing Transmission Fluid (TCI® Part #950600) and Max Shift™ Synthetic Transmission Fluid (TCI® Part #950650). Either will work well in our Circlematic™ Transmissions. They both will lower the temperature of the transmission by up to 30°, but with the synthetic blend you can get more laps before a change is needed. In addition, make sure things like the rear suspension are correct, and check for loose nuts and bolts.

How do I choose the right torque converter for different sized short tracks?

Actually, we prefer you to call us at TCI® for that recommendation. The last thing that we want is for you to get the wrong converter. There are a lot of variables to consider, i.e.; rear gear ratio, tire size, cam specs, engine cubic inch, track length, lower end rpm and weight. There is no set easy answer “chart” available for a torque converter selection.

How do you set up the clutch on a pedal style Circlematic™?

We recommend using a hydraulic clutch pedal with a push-type cylinder to activate the detent lever. Mount the slave cylinder to the transmission bellhousing. Just drill your bolt holes into the bellhousing, and mount a bracket that will hold the slave cylinder securely
in place. The detent lever must move 1/2-inch to the rear of the transmission to allow the body to fully release or "dump" the pressure. The TCI® return spring must be mounted to the detent to provide sufficient force to return the detent lever against the stop.