Effective cooling?

[SS402]

Unless the electric fans are pulling 4000+ cfm its gonna run warmer than you like, when i switched back to a mechanical fan my coolant temps dropped from 220+ down to 178 and holding, i also prefer a restrictor plate to a thermostat.

If there is no crossover in the back of the manifold a bypass will help to pull temps down in the back of the block and heads.

Use a higher psi rated radiator cap.

Run straight water and pop the lower hose when its gonna freeze.

Install colder plugs.

Use a vacuum advance distributor and hook it up to manifold vacuum.

Don't underdrive the waterpump, it should run 1:1 with the crank or a max of 15% overdriven.

[Socrace]

Had a similar prob and decided to check for clogged radiator tubes using an IR heat gun. Found that most tubes on the front of the radiator were hotter than tubes on the back of the radiator. A real WTF!? moment for sure. Finally figured out that air was being sucked by the fans backwards *through* the radiator core just outside the fan area.
Bottom line, if electric fans are mounted real close to the radiator core and no shroud, try spacing them back more like a mechanical fan, to spread low pressure across the whole core.

Bob D
Yet Another EFI Project: http://users.ameritech.net/socrace/Main2.html

[quickd100]

I've had a similar problem with my 605. I tried one of those Electric fans and it couldn't keep up. I'm going back to a mechanical. I've got a 5 blade and a 7 blade fan. I'm installing the 7 blade tonite and take it for a spin. I'll post the results.

[quickd100]

I'm afraid I can't report any results Tonite. I fired the Hemi up and it was making ugly noises from under the driver's side valve cover. Pulled it off and found I'd split #3 intake rockerarm. At least it didn't happen at 7500 rpm.

[jake197000]

maybe your water pump is pumping too much so the coolant doesnt spend enough time in the radiator.electric fans are better at pulling air through the radiator than pushing it.fan shroud can be huge also.

[jsgarage]

Maybe I missed the memo, but in my experience, 190-220F in almost all street or semi-street cars is not "running hot" but is actually about right for min. wear. "Hot" is when the thing upchucks green fluid all over the ground while stationary at idle. I also do not trust stock dash temp gauges to read right unless you've checked it with a calibrated source.

My wife's commuter Z-28 runs that temp most of the time and the gauge says 245F is 'warm' (around town speed and max AC in 100 F weather) while 260F is 'hot'. An IR gun verifies it runs in that range. Her '97 is stone-stock with 50,000 CA & Nevada miles- for some reason she won't let me touch it with tools in my hands....

[Circlotron]

o If you try raising the back of the hood, tape a few wool tufts along the opening and see which way the wind blows. Most times I've tried this the air flowed in rather than out, thus pressurizing the underhood area and reducing rad air flow.

Yep. The area between the base of the windshield and the hood is a high pressure area. That’s one reason why the passenger air vent grill is placed there. Same deal with bonnet scoops with the opening facing rearward and close to the windshield. Jacking up the rear of the hood may well cause air to flow in, not out, as MadBill says.

[peejay]

maybe your water pump is pumping too much so the coolant doesnt spend enough time in the radiator.

You want to coolant to flow AS FAST AS POSSIBLE.

The goal is not to make the coolant cooler, the goal is to remove heat from the engine.

[steve cowan]

maybe your water pump is pumping too much so the coolant doesnt spend enough time in the radiator.

You want to coolant to flow AS FAST AS POSSIBLE.

The goal is not to make the coolant cooler, the goal is to remove heat from the engine.

I would like to see data results for flow in a specific cooling system as the pressure goes up, I would think as pressure increased the flow rate decreased??

[jake197000]

getting the coolant cooler is removing the heat from the engine.the why do some people run restrictors ?

[1989TransAm]

I have a similar problem with the LS-427 in my 1965 Buick Skylark. The way the front is constructed it is hard to get a wide radiator in there. I will be following this thread.

[jake197000]

pure water does transfer more heat than a freeze has a lower boiling point though.if it aint spitting out coolant its not too hot.

[Steve.k]

I've found for street use most of the aftermarket fan systems do not pull enough air. I've use used dual fan systems out of a intrepid Chrysler with good success. They are narrow and install easy where room is tight. I usually take the 3spd mode and wire it to full speed. It will keep my 700hp drag motor cool on street usually in 180 range. Also on other vehicles I'll stick in a factory style truck fan that came in pickup that is not thermostatic they pull a ton of air as long as you have shroud. Most vehicles without shroud will heat in traffic that I've done. The shroud maybe one of the most important pieces.

[peejay]

getting the coolant cooler is removing the heat from the engine.the why do some people run restrictors ?

To increase pressure in the block to raise the local boiling point. Radiator cap pressure is just radiator pressure, the block pressure is going to be much higher than that. And you need that boiling point increase, local metal temperatures at the spark plugs and exhaust valves is going to be WAY over 212F. I have SAE papers showing metal temperatures near the spark plugs of over 400F on some engines.

If all you care about is making the coolant cooler, don't pump the water at all. The coolant in the radiator will never get hot.

If you want to move BTUs out of the engine, run the coolant as fast as possible. The radiator efficiency goes up as it gets hotter than the air, and if the coolant moves slowly then the radiator gets less efficient as you get towards the bottom (or outlet side). So fast moving coolant uses the whole radiator. Likewise, if it moves slowly through the engine, the engine is going to be thermally irregular. Move the coolant as fast as the water pump will let you.

Notice that the OEMs are moving away from belt driven water pumps. They don't want the cooling system to be tied to engine RPM anymore. If you do that you either have a water pump that stalls before redline or you have an insufficient cooling system at low RPM. This is especially important when everything is turbocharged and is expected to make boatloads of torque (and heat) at low RPM.

[Steve.k]

getting the coolant cooler is removing the heat from the engine.the why do some people run restrictors ?

The restrictors are basically a orifice that regulate flow like a stat. However you always have water circulation which is good. They work very well once you get the correct size in. No chance of a stuck stat.