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Old 06-27-2009, 08:38 AM
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Originally Posted by redride
This is a fresh motor and seems to run hotter than my 396 did. The 396 ran mostly around 190 and the 502 will run as hot at 205--both with short drives around town. My question-- is a dual pass radiator better at cooling than my single pass radiator?
A single-pass system- if adequately sized- will do fine.

The water pump's drive ratio is often overlooked when a cooling issue arises. I'd suggest you go to at least a 1:1 W/P to crank drive ratio, to as much as 1.3:1 (W/P overdriven).

This flies in the face of "power saving", "HP freeing" underdrive pulleys that are sold in the aftermarket. While an underdrive set-up CAN reduce the parasitic drag on an engine, it does nothing good AFA cooling the engine goes. If I were to have to choose between an "extra" 5-10 HP or an engine that runs @ 190 degrees as opposed to 220 degrees, I'll take the 190 and eat the HP "loss". This doesn't necessarily even apply to the OP- but is an issue w/a lot of guys looking to do simple, "computer-friendly" modifications to their Mustangs and Camaros.

With the use of electric fans, the HP savings can amount to as much as 25-plus HP over those crappy plastic flex fans. Even a good clutch fan set-up can use up 10 HP pretty easily, so use some of that savings on turning the pump faster, IMO.

The electric fan shrouds typically don't cover the entire surface of the radiator. Most shoot for about 70%-plus, Flex-a-lite says a minimum of 60%. Obviously, more is better as long as the fan is adequate for the app.

Does the engine cool down at highway speeds?
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