Stumped with cooling issues...please help

[Rick 91GT]

Well I have a Ron Davis Radiator, 180 thermo and a Stewart High Flow water pump, 16" Perma Cool fan, no A/C so the radiator see's all the air. 100% water with a rust inhibitor..

Crusing through town or low rpm my car gets hot 200+ degress once I get going down the road it cools down, so I know the radiator is fine, the flow in it is great. I was at the track and when I left the line my car was at 200 degrees, on the N20 I was trapping at 224 degrees.

I was told by Stewart that I can spin this pump either way since the design of their impeller is different that a stock piece. Well I tired that over the weekend with minimal changes, it runs a tad cooler. I have no heat in the car so the water goes through nothing but the motor and the radiator, should I go back to a 195 thermo like a stock piece. I thought I was having belt wrap issues due to this March tensioner set-up, but now I have almost 4" of wrap and it still doesn't run nice and cool like it should.

Any ideas?

[89 ATI]

I was having the same problem with a perma cool fan. I went to the stock fan set up and have no more problems. I had forgot how much air a stock fan could move. Feels like a small tornado under the hood.

[Rick 91GT]

Talked with Jack Wilson at Stewart he told me my problem is my Crank pulley is smaller then my water pump so I am under driving the pump, he said there is no benefit in this. Told me you need 10-35% ratio difference between the water pump and crank to be efficient, if I swap pullies it should solve all my problems. You need to under drive the pump when you see a constant 7000rpm to keep it from cavitating, they do this on the Nascar pumps they provide.

I have no idea where my stock pullies are, guess I need to see if I can find a set of stock pullies.

[magicmerll]

I can't believe that nobody has mentioned the obvious....100% water? Why no ethylene glycol?

Antifreeze/Coolant raises the waters ability to store heat, thus reducing temperature and boiling point. Try a conservative 70/30 mix of water to coolant. Underdriven pulleys get blamed for cooling problems more often than they should, and of course the water pump manufacturer wants you to spin their pump as fast as you can.

Also, if you're fan is less than 18" diameter, and you have any serious engine mods, you are simply not getting enough air! Notice how the car cools once you get down the road? That's because it's moving more air!!! Don't put the power-sucking factory fan back on this car. Simply upgrade to a larger fan, or try installing a 'pusher ' fan on the opposite side of your radiator.

I have had these cars going 12's with the stock cooling system. There is no reason to have cooling problems, period.

[Rick 91GT]

Actually water is the best coolant available, have been told this for years...at the track you are not supossed the run Anti-freeze, it makes clean up a pain if any were to spill and is very slick if it gets on your tires. I have tried a 70/30 mix and it doesn't help at all, tried the magic additives as well, Water Wetter, etc...

Here's a quote right from Stewarts Website..

Tech Tip #4 - Coolant, Fans, and Hoses

Coolant

UNEQUIVOCALLY WATER IS THE BEST COOLANT! We recommend using a corrosion inhibitor comparable to Prestone Super Anti-Rust when using pure water. If freezing is a concern, use the minimum amount of antifreeze required for your climate. Stewart Components has extensively tested all of the popular "magic" cooling system additives, and found that none work better than water. In fact, some additives have been found to swell the water pumps seals and contribute to pump failures.

In static cooling situations, such as quenching metal during heat treating, softening agents (sometimes referred to as water wetting agents) will allow the water to cool the quenched part more evenly and quickly. The part will cool quicker, and the water will heat up faster. However, an automotive cooling system is not static. In fact, the velocities inside a cooling system are comparable to a fire hose forcing coolant against the walls of the engine's water jackets. If the softening agents actually aided in cooling the engine, the temperature of the coolant as it exited the engine would have to be higher because it would have absorbed more heat.

Fans

Electric fans have improved tremendously in recent years, in both quality and reliability. Electric fans now outperform mechanical fans in nearly every application, except towing and dirt oval track racing.

When using a mechanical fan, a properly designed shroud must be used. Most mechanical fans are not designed for high RPM use: they can have serious vibrations problems, due to air turbulence, when run over 6,500 RPM. This is a turbulence problem, not a balance problem, and will destroy the water pump and components in front of it. The large fans preferred by dirt oval track racers can consume up to 18 horsepower at 6,500 RPM. Do NOT run a mechanical fan that is any larger than required for the application.

Flex fans are a poor design for performance applications. They move less air at higher RPM, and only consume a fraction less power than standard fixed pitch fans.

Clutch-style fans are inconsistent and we do not recommend their use for any application, if possible.

[PKRWUD]

Originally posted by magicmerll
I can't believe that nobody has mentioned the obvious....100% water? Why no ethylene glycol?

Antifreeze/Coolant raises the waters ability to store heat, thus reducing temperature and boiling point. Try a conservative 70/30 mix of water to coolant.

That quote from Stewarts website is EXCELLENT!

What follows is my quote that I usually leave for people that don't understand:

A 50/50 mix in the radiator is WAY too much coolant! Especially in warm climates. You will rarely ever require more than 30% coolant/anti-freeze, and even then, only if you live within the Arctic Circle. 20% would be more practical. Coolant serves five purposes, none of which keeps the engine cooler. It:
1) Acts as a lubricant for the water pump.
2) Helps protect the hoses from the inside (BTW, save your used coolant for wiping down your tires! It will restore the "new tire" look, rather than the "glazed donut" look you get with aftermarket tire dressings).
3) Helps reduce the electrolysis that naturally occurs in cooling systems that deteriorates metal. 4) Lowers the freezing point of the cooling system mixture
5) Raises the boiling point of the cooling system mixture.
This last one is the most deceptive. A cooling system in proper working order is a sealed system. That means that no outside air can get in, and as the temp rises, the system becomes pressurized. Pressure, combined with no added air, will keep the system from boiling under normal circumstances. By raising the boiling point, coolant actually raises the cooling mixture temp. The info on the sides of the coolant containers brag about being able to reach 260 degrees before boiling over, but guess what: DAMAGE CAN OCCUR AT OR BELOW 260 DEGREES!!! You want it to boil over before it gets that hot! That way you will stop driving, and let the system cool down. Coolant also retains heat, which makes it harder for the cooling system to dissipate the heat, like it's supposed to. Here in California, I never use more than 10% coolant, even when I go to the snow in the mountains. I worked for Bill Elliott in 1998, and was shocked to discover that those cars, with their 900 horsepower engines that drove for 500 miles straight, averaging 7000+ rpms, ran with 100% water in the cooling system. The only thing they use coolant for in NASCAR is to measure the cc's of the combustion chambers in their heads. Because they don't use coolant, they have to use a higher pressure rated radiator cap (28 - 30 psi), but since everything is new, it can easily handle that much pressure. Don't believe the hype: coolant actually makes your engine run hotter!

Take care,
~Chris