TORCA Tech Tips
Corvette Cooling

Corvettes, and most modern vehicles, are very reliable when it comes to keeping cool, as long as air is passing through the radiator, by the car physically moving through the air or by the use of supplimental fans in-line with the radiator. In sporting events like autocrosses and funkhanas, competitors find themselves waiting in line for their turn with their engines running, sometimes behind other cars, which does not allow movement of the air. The temperature shown on the gauge will rise, especially right after a spirited 1 minute run through an autocross course in 1st gear. Because the events that TORCA participate in are at 5000 feet elevation and above, we have much less density of air going through our radiators. The higher the density, the more thermal capacity the air has to take the heat away from the engine. The following are ways to keep your engine temperature below 220 degree F.

Steps to take while running:

You will notice that many competitors will immediately pop and lift their hoods when they are back in the grid, to help vent hot air out of the engine compartment. This helps move the air through thre radiator, especially if there is a breeze. Make sure someone is close by if you don't want to unstrap yourself out of the car to put it back down.

If you find that you have to stay with your car with the engine running for staging purposes, many competitors will turn on their air-conditioners. This has a two-fold benifit. One: Operating the A/C turns on the electric fan which forces air through the radiator. You should notice the temperature moving down after 30 seconds or less. Two: it keeps the drivers cool while waiting around in 95+ deg heat with their helmet on. Make sure you hit the A/C OFF button before you launch, or you'll be losing horsepower!

Steps to Improve the Coolant:

When cars get very hot (more noticable on older C3's than C4, C5 and C6's) they sometimes will start venting coolant on the ground which becomes a hazard for other drivers if the slippery anti-freeze gets on the tires. Because anti-freeze is so slippery, it is not allowed in race cars or water cooled motorcycles on paved courses. Most people are under the impression that the more anti-freeze you put in the radiator, the cooler the engine will run. Its the exact opposite, however, since anti-freeze is NOT a coolant. The following table shows the thermal conductivity of various materials in your engine and the chart shows cylinder head temperatures with various ratios of water, Glycol, and Water Wetter:


Click for larger

Water in the cooling system is capable of transferring twice as much heat out of the same system as compared to a 50/50 glycol coolant and water solution. Consequently, the best plan, if you are losing coolant due to over heating, is to add straight water back into your coolant reservoir. The is an additive, Redline Water Wetter, which helps reduce the temperatures of engines.

The tests above were performed with a Chevrolet 350 V-8 with a cast iron block and aluminum cylinder heads. The thermostat temperature was 160°F. The engine operated at 7200 rpm for three hours and the stabilized cooling system temperature was recorded and tabulated below: Redline Water Wetter Flash Demo

Cooling System Fluid Stabilized Temperature
50% Glycol/ 50% Water 228°F
50/50 with WaterWetter® 220°F
Water 220°F
Water with WaterWetter® 202°F

These numbers are similar to the temperatures recorded in track use and heavy-duty street use. Most local speed shops recommend a 20% Glycol and 80% water with the addition of Water Wetter. Since Corvettes are hardly ever left outside in below zero weather, you do not need any more anti-freeze than that.

Water Wetter Directions: One 12 ounce bottle treats 12-16 quarts of water or a 50% ethylene or propylene glycol solution. In smaller cooling systems, use 4-5 caps per quart. Add directly through the cooling system fill cap into the radiator or into the overflow tank. Do not open a cooling system while hot. For best protection for aluminum, replenish or replace every 15,000 miles. The anti-scaling ingredients in Red Line WaterWetter® allow its use with ordinary tap water. However, using with distilled or deionized water will accomplish some scale removal in the cylinder head area. Plain water with or without WaterWetter® should not be used in cooling systems containing magnesium - antifreeze should be used - with WaterWetter®. For maximum temperature reductions use the most water and the least antifreeze possible to prevent freezing in your climate. Even in summertime the use of air-conditioning can blow freezing air through the heater and cause freezing of the heater core unless approximately 20% antifreeze is used. Red Line WaterWetter® is available in 12 ounce containers.

Parts of the above are taken from Redline Technical Information: Redline Water Wetter Tech Info

Steps to Improve the Cooling System:

Corvettes typically come from the factory with a 195°F thermostat. This is the temperature that the thermostat opens to allow coolant to flow through the system. The lower you make the thermostat, the sooner the coolant will start flowing through the radiator, and generally, the cooler your engine will run. The 190°F thermostat is great for getting your compartment warm in the winter, but does not help you at sporting events. 180°F and 160°F thermostats are available (from Hypertech for example) for Corvettes and are an easy swap in most Corvette engines.

You can have the fans turn on automatically at a lower temperature (just as you did when you manually turned on the A/C), by having a shop with LS1 edit to reprogram your Vette's computer to adjust the break points (what temperature the fan turns on and what temperature the fan turns off).