Cooling issue on highway

Bewy said
[1] And lots of people use 180 [ or 160 ] thermostats in their old cars NOW. When these cars were made, the fuel had lead in it which cooled the combustion process & reduced the chance of detonation. No lead to day, cooler engine by whatever means, to reduce chances of detonation.
[2] New cars have much more alum in them than old cars [ look it up ]. Easier to cool because of it's greater thermal conductivity compared to CI.

Just because a lot of people run 160's (flat out stupid in anything other than a drag only car) or 180's in their car's now doesn't mean a thing. I would wager a lot of them don't even understand that the thermostat has nothing to do with how hot the engine runs, it merely sets the low temp limit. Let alone understand basic thermodynamics.

I am well aware that new cars use more aluminum. But they also run higher exhaust temperatures, higher compression, ridiculously tightly packed engine compartments and typically use smaller grille openings for improved aerodynamics. There are a lot of factors, but in general new cars have much higher cooling requirements than our old stuff. They also almost exclusively use electric fans, because they're more efficient.

RustyRatRod said
I might be wrong, but I don't have a choice. I don't have enough room for a clutch fan. I don't have enough $$$ for an electric fan. At least not right now.

Hey that's fine man, you do what you need to do. Lots of different situations and builds out there and there are good reasons for running either type of fan.

But, that doesn't mean that electric fans aren't far more efficient. I honestly don't care what someone runs, I'm just tired of the old "electric fans don't work" argument because its completely untrue. People set up bad systems and blame the fan for their poor execution.

George Jets said
This is the 18" silent run fan, 3/4" away from the radiator, no shroud, aluminum radiator.

The blades don't flex, the design cuts the air instead of chopping it so they run quiet and don't rob extra power.

Tight quarters with the serpentine belt dress up kit that pushes everything forward, this fan cleared everything easily, and is keeping the big 440 with headers running cool. No Shroud.
$65.00 shipped in.

View attachment 1715953335

You can even see here the electric fan and shroud setup was actually rubbing the center of the aluminum serpentine water pump pulley in the tight quarters.

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Got a nice job of machining down the aluminum serpentine pulley so the silent run fan would bolt up with the proper spacer.

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As a mock up example here is the first silent run fan setup:

View attachment 1715953338

________________

For those who are curious about the the "Flex Fans".

Here is a picture of one that is 18", makes lots of noise, robs power, and won't clear in the tight quarter situations like Elephant Ears, serpentine belt setups/dress ups, and just plain tight quarter layouts.

View attachment 1715953339

☆☆☆☆☆

First, you left off the most important part- How many CFM does it pull, and what is it's output at different RPMS? If you don't know that, you can't argue it's a better fan.

Second, running without a shroud is terribly inefficient. Shrouds increase the amount of air your fan can move and pull it through the radiator where it is doing the most good.

Third, those thin sheetmetal blades absolutely flex. Maybe they flex less than the more standard flex fan design, but they 100% still flex. That's why they're riveted on. If flex was not part of the design they'd be solid blades instead of a thin blade riveted to a more solid base.

And finally, if your electric fan rubbed you chose the wrong electric fan. That's not the fault of electric fans in general. I run a serpentine belt system on my Duster with my electric fans and have no interference issues.

mopowers said
Not quite. Out of curiosity, I looked it up. It seems to vary depending on the year.

Here's what the '66 Dodge FSM says:
View attachment 1715953340

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'68 Plymouth FSM:
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'69 Dodge FSM:
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'73 Dodge FSM:
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Well you got me. All of my 318 cars had 195's in them, I probably shouldn't have assumed they were factory just because the parts houses list them as the stock replacement. Thanks for pulling that stuff up.