MAZDA COMPETITION RACE RADIATOR

Third generation RX-7's are notorious for having marginal cooling systems. Simply put there isn't enough space under the hood to get adequate airflow nor enough room to mount a properly sized radiator. Perhaps in unmodified form the stock radiator might be adequate but the minute power increases are demanded of the powertrain and when driven hard for extended periods of time the inadequacies of the stock cooling system become readily apparent. This is perhaps the reason that one of the first things to add to your vehicle is an aftermarket coolant temperature gauge. The stock temperature gauge is so heavily weighted so as to be next to useless until it is too late. Given the intolerance of rotary engines to an over-temperature condition this gauge is totally useless except to inform the driver when to pull over and call a tow. Therefore in the interest of preserving my car for track use I decided to install the Mazda Competition upgraded race radiator.

The Mazdacomp radiator consists of a core section 150% thicker than the stock unit and has welded aluminum end tanks verses the stock radiator with plastic end tanks. In defense of the OE radiator it was about half the weight of the Mazdacomp unit. In this area though I think dependability outweighs the benefits of saving a few pounds. installation was fairly straight forward. The Mazda service manual was very helpful. To begin one must remove all the intake plumbing and the intercooler. The airbox, intercooler ducting and battery and tray must also be removed. Because the radiator is attached at the lower points to the front sway bar mounts, the undertray and sway bar and mounts must also be removed.

Comparison: Mazdacomp (top), Stock with fan assm. (bottom)

Oh my God! What have I done? (radiator and plumbing removed)

New Mazda Competition radiator installed with new hoses (bottom)

In my case I merely had to remove the radiator support plates from the CWC mounts and not remove the mounts themselves. The manual specified removal of the stock radiator from below but I found removal from above to be the least painful. I'm sure if the car had been on a lift the lower route would have been easier. Removal from below would also require slightly bending the AC condenser out of the way to clear the path for removal. With the old radiator removed installing the Mazdacomp was easy. transfer the fans from the stock unit and drop in the new assembly. While installing the Mazdacomp I also decided, while I had everything apart, to also replace the main upper and lower radiator hoses and also use screw clamps in lieu of the OE spring clamps. However, given the simplicity of the dropping in the upgraded radiator itself there is more work to be done. The OE radiator is sealed to the car with lots of foam. the Mazdacomp on the other hand has only some alloy flanges. So one must fabricate side shields to seal the radiator. I used thin-wall SS sheeting and formed the side shields around existing piping and used prethreaded holes as locations for fixing the shields in place. See pictures below

Left side custom fabricated side shield ducting	Right side custom fabricated side shield ducting

If you would like to contact me and converse about my experiences with my 7:
please feel free to send an e-mail to rotarypower@rx-7.net

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