Quick Tech
Turn Any Tach Into a Memory Tach

Circle Track Magazine, September 1995 Text and Photography by BOB CARPENTER

Memory tachs are a great tool. You can select a better camshaft by comparing the lowest rpm your car sees in a turn with the highest rpm the engine spins at the end of the straight. Knowing your power-spread requirements can eliminate a lot of guessing. A memory tach can help you analyze the success of gearing changes, determine if carbueration changes are working, and even help compare the high and low lines on the track.

Trouble is, of course, you have to pay a premium price for a memory tach. Since most racers have an ordinary tachometer in their car already, the Tach-Mate from Czech-Mate Enterprises might be a good way to upgrade. This device intercepts the signal from your ignition and remembers it for either eight or 30 minutes (depending on the model you choose). The Tach-Mate sends the signal back out to your tach: so, if you choose, you can still watch it manually during a race.

The Tach-Mate consists of a switch panel and a control box. The panel should be close to the driver, but the control box can go in a variety of places. It is most important to avoid heat and direct sunlight.

We put an eight-minute model in the Saturday Night Buildup Street Stock and tested it out with great success. One other important feature is that the Tach-Mate can be used as a diagnostic tool to check out the accuracy of your tach. By flipping different switches as outlined in the instructions, the Tach-Mate actually drives the tach. First, it goes to 1000 rpm, then 2000 rpm then 3000 rpm, and so on. Any false readings and you know you've got a problem with the tach. I wish I had a Tach-Mate installed last year when two different tachs gave me trouble. It would have saved me a lot of frustration.

With the Tach-Mate installed in your car, you can find out what your engine was doing when you were too busy to notice. Knowing the minimum and maximum rpm you typically reach during a race is very helpful information.

What did we learn with the Tach-Mate? Our car was getting down to about 5000 rpm in the turns and peaking out at about 7500 rpm on the straights with occasional spikes to 8000 rpm when wheel spin was not controlled with throttle sensitivity. The recall mode can be played back in three speeds: real time, slow, or fast. There's also a "high rpm" switch that gives you a quick look at your maximum rpm. We mulled our tach information over and considered that our 4.33:1 gears were too steep for the track. However, since no one else was on the track with us during testing, we concluded that traffic and normal racing conditions would keep speeds and peak rpm down a bit. The ability to accelerate out of the turns was more important. At least we know. If we do make a gearing change, a tire-diameter change, or any other change, we'll have solid information to use for comparison.

Wiring the Tach-Mate is surprisingly simple. One wire to ground, one wire to a 12-volt power source, one wire to the tachometer, and one wire to the ignition. Even someone afraid of wiring (me) can do it in about 10 minutes.

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