Allum Radiator choices

[WSSix]

Originally Posted by Vegas69

That's ok in a factory situation where big horsepower is usually not under the hood. Let's face it....horsepower is heat. Who had ever had trouble cooling an engine driving down the road? It's all about city driving at low speed. That's when you need that full shroud and dual spals kicking aise non stop. Especially when it's 100 degrees 5 months a year.

Very true but the C6 Z06 and I'm betting ZR1 don't have a full shroud. No C5 or normal C6 does. You're also not producing huge horsepower sitting still or idling in traffic so you're not producing any more heat. Of course you have to know the capacity of both the fan and radiator before you can say if a partially cover radiator/ fan combination will work.

[Vegas69]

True but my c5 fan turned on at 232 degrees. Don't need much snort on your fan to maintain that temp. Carbs hate heat and it's not that optimal. 600 hp car still makes more heat at idle than 350. It's all relative. I have a dual fan with full shroud and I can't get any heat in mine when it's 70 crusing. 180 stat and it runs 150-165 on the highway. Summer it runs 180-190 with full shroud at speed. Keep in mind the factory is going to use what it can get by with. For us hot rod builders we want our temps in a specific range and it's usually around town idling that causes issues. On the track then no shroud is probably ok.

[chicane]

Originally Posted by Vegas69

In a racing situation I absolutely agree.....5000 cfm out of one fan?

Yup... although, I have heard a number of quotes between 4800 to 5500 cfm... so I just call it 5k to err with some safety factor.



Here is a discussion on this very subject from a couple of years ago, RE: Bad Penny 1.0.

Mind you that the number that Carl quoted for operation temperature and its max value... was when he was killing it on the track. The actual street temperatures... were even better. In fact... the specific system is so efficient... that it requires an oil thermostat to keep the temperature in it. And thus... without a shroud.

At higher operating speeds... the shroud will only hurt. But that would be braking the law.

[WSSix]

Originally Posted by Vegas69

True but my c5 fan turned on at 232 degrees. Don't need much snort on your fan to maintain that temp. Carbs hate heat and it's not that optimal. 600 hp car still makes more heat at idle than 350. It's all relative. I have a dual fan with full shroud and I can't get any heat in mine when it's 70 crusing. 180 stat and it runs 150-165 on the highway. Summer it runs 180-190 with full shroud at speed. Keep in mind the factory is going to use what it can get by with. For us hot rod builders we want our temps in a specific range and it's usually around town idling that causes issues. On the track then no shroud is probably ok.

The reason the temp gets so high in your C5 is tuning for emission reasons, nothing more. The factory fans are very strong. After tuning and a 160* stat most C5s run 190-205 all the time. C6s use a single fan with a delta controller to maintain a certain temp with every varying fan speeds which is better for the engine versus cyclic heating up and cooling down that an on/off fan setup causes.

You're right it is relative and the whole picture must be looked at. You can have different block designs and cylinder wall thickness greatly affecting coolant temps. Horsepower alone is not the only variable. For instance, in a few weeks I'll have completed a 600+ hp C5. It will not run any hotter than stock at any time other than when I put it under boost. It'll have factory everything cooling wise because it's a street car. Our last blown C5 made 550hp and had no issues cooling.

Also, if you're coolant temps really are that low, are you sure your oil temps are adequately high enough? There is such a thing as too cold for the engine.

[Vegas69]

I have been a little concerned about that actually. I should take a oil pan reading next time out. What is minimum oil temp reccomended? At 150-165 cooland I am assuming oil temp of 175-190. Engine takes forever to get temp in it initially as well.

[WSSix]

If you have those oil temps, you're fine. I believe 180* is the "magic number" for oil temps. I'd personally find a way to add an oil temp gauge. Do you have a volt gauge? I'd get rid of that for an oil temp gauge in a heart beat if you can.

[chicane]

Engine oil temperature (operational values) are considered best when the engine oil temperature is maintained at 20 to 30*F above that of the water temperature. See the link to a discussion below.

Not to mention that you best volumetric efficiency is going to be between 195-215*F. Keeping the oil at 215* or better will allow the additives in the base oil product to do their intended job.

Here and here are two discussions of engine oil temperature from a few years ago.

[Vegas69]

From my brief look online 180 looks dead on. I can install one on my oil filter remote mount. Sounds like a good idea. I think I'll pull the dipstick next time and take a quick reading with my infared gun. I bet it's real close. 25-30 degrees above coolant temp seems pretty average.

[chicane]

180* for engine coolant (and automatic transmissions) and 215* for engine oil is considered to be near perfect.

IR isnt going to tell you the temperature... just the surface temperature of the medium that you are looking at (not saturation temperation). You need an immertion probe type transducer to give you an accurate reading.

[Vegas69]

Dipstick is submerged in the crancase...just want a vague reading to start with. Maybe a good idea to go to a 195 t stat in the winter here. I added water wetter and more water since summer and it's really made it tough to put heat in the motor. Around town it will run 180 but on the road 150-165 in norm. Remote oil filter is probably not ideal for a temp gauge either.