In our engines at 500+ rwhp, we are putting in far more heat into the internal parts than they were designed for. The water jacket doesn't get larger, nor does the water pump flow more when we increase the heat. To cool these internals you have four things that can be used to remove the heat:
Intake air: This has the least effect. The mass of the air per revolution is just tiny, and air itself sucks at removing heat, or we'd all be driving VW Beetles still.
Exhaust air: Keeping the exhaust air cooler (EGT's) is the best way to keep the turbines and exhaust valves happy. But to make big power, you're going to run more EGT's, not less, than stock, so it's actually a negative as far as increasing cooling over stock.
Oil: This is doing most the work, and it is cooled by the water.
Water: This is the only effective means we have of removing more heat from the internals. Whether you get best MPG at 225 deg like a Corvette does is irrelevant for racing. If you increase HP, that 225 deg system is not going to hold up. Obviously they don't run 225 deg sustained when racing them, they first modify the cooling system.
Something to ponder though. People have blown out water jacket plugs without "overheating". I can tell you that this is impossible if your head gasket is holding. Unless water is boiling, it cannot generate enough pressure to blow out a plug. Or our trucks would blow out their plugs at stock power level at 4500rpm when grade-braking. That is when the water pump is making maximum block pressure. The return restriction is fixed, the water pump increases pressure as a function of RPM.
So what is really happening? The temp you see at the return is the average water temp. Not peak. Areas in the block and heads boil water when you crank up the power, and this increases internal pressure. As the steam travels away from the hot spots, it mixes back into the cooler water, and averages out the temp you see at the return.
I guess I'm catching flak from two directions by starting this thread:
A) I'm announcing it prematurely, further testing should be done.
B) I'm keeping it secret, not telling people about it.
It's not like I'm ever going to win in such a situation. Nor am I going to make money selling a handful of thermostats to hardcore racers for a couple of bucks. Nor am I motivated by money, or I'd quit racing and spend more time at my real job.
Intake air: This has the least effect. The mass of the air per revolution is just tiny, and air itself sucks at removing heat, or we'd all be driving VW Beetles still.
Exhaust air: Keeping the exhaust air cooler (EGT's) is the best way to keep the turbines and exhaust valves happy. But to make big power, you're going to run more EGT's, not less, than stock, so it's actually a negative as far as increasing cooling over stock.
Oil: This is doing most the work, and it is cooled by the water.
Water: This is the only effective means we have of removing more heat from the internals. Whether you get best MPG at 225 deg like a Corvette does is irrelevant for racing. If you increase HP, that 225 deg system is not going to hold up. Obviously they don't run 225 deg sustained when racing them, they first modify the cooling system.
Something to ponder though. People have blown out water jacket plugs without "overheating". I can tell you that this is impossible if your head gasket is holding. Unless water is boiling, it cannot generate enough pressure to blow out a plug. Or our trucks would blow out their plugs at stock power level at 4500rpm when grade-braking. That is when the water pump is making maximum block pressure. The return restriction is fixed, the water pump increases pressure as a function of RPM.
So what is really happening? The temp you see at the return is the average water temp. Not peak. Areas in the block and heads boil water when you crank up the power, and this increases internal pressure. As the steam travels away from the hot spots, it mixes back into the cooler water, and averages out the temp you see at the return.
I guess I'm catching flak from two directions by starting this thread:
A) I'm announcing it prematurely, further testing should be done.
B) I'm keeping it secret, not telling people about it.
It's not like I'm ever going to win in such a situation. Nor am I going to make money selling a handful of thermostats to hardcore racers for a couple of bucks. Nor am I motivated by money, or I'd quit racing and spend more time at my real job.
