REspeed Rotary Engine Blog

Mazda Rx8 cooling issues | Performance upgrades

Written by MazdaDoug | Jul 10, 2023 2:50:55 PM

Rotary Engine Builds | We do like the Mazda Rx8, with its excellent chassis and power to weight ratio it is a solid performer.

How about here in Colorado where the high altitude and low humidity doesn't do us any favors?

 
Our motors tend to run hot, add enough hits to redline (to have fun) and the motor starts its decline.
The rotary engine doesn't like high coolant temperatures, and another thing is the oil coolers tend to get beat up cooling fins reducing the heat transfer and again increasing core operating temperatures.
 
  • How do we get that under control?
 
First, we check all cooling components for proper operation, do the cooling fans turn on as they are supposed to? Our Snap On scan tool shows if that is working properly.
 
Second, we look at the oil coolers for fin damage. Most of the time we can spend the effort to straighten the fins, after that we look at the thermostats inside each oil cooler.
 
Personally, I remove them and install a passage plug so they work all the time. Allowing the engine to warm up on cold starts is highly recommended anyway. The issue is that if / when those OEM thermostats plug / gum up there isn't any indicator that they have so you will never know until you remove / inspect them.
 
Once the radiator and oil coolers are operational (all our builds get the 30% larger radiator upgrade), we install nascar stainless steel wire mesh in front of the oil coolers with foam on the sides (of each cooler) to keep air flowing through the cooler instead of around it.
 
For high performance applications, we recommend cooling fans on each oil cooler with them automatically turning on when radiator fans turn on or install additional gauges for temps that signal fans to turn on at a specific temperature. Details matter.