Coolant flow

72bluNblu said
"Packing up", as you put it, is a rare problem usually only associated with flat plate style shrouds that come on the cheapest of cheap aftermarket electric fans. If a fan's shroud has flaps, that should be a dead giveaway is wasn't actually designed to flow air and that it was just slapped together and band-aided. There are a lot of aftermarket electric fans and shrouds that have no business on cars- their fan CFM ratings are too low, and their shrouds are simply a way to mount their cheap fans, not actually flow air.

I did read what you wrote, and you said "good mechanical fan" was necessary. It's not, a good electric fan and shroud work great. Maybe that's not what you meant, but that is in fact what you said.

You should care, because getting it wrong can mean cavitation in the water pump. The cars that had 1.3:1 and 1.4:1 pulley ratios had pumps with fewer blades. The reason is the RPM of the pump and cavitation, not the amount of water it's pumping. Running a high flow pump is good and the idea you can flow water too fast is silly, I agree. But, you still have to consider the RPM of the pump and how it's being driven. A 1:1 pulley ratio with a high flow water pump is one solution, but if your pulley ratio is 1.4:1 you need to account for that too. Some of the pumps are designed differently now, but the factory was looking at the pumps driven speed and adjusting the blades accordingly.

The majority of your points are right on and I agree, but you leave science behind on this point and just go with what you're personally familiar with.

The 180° temp thing is just left over from your drag racing background. Not every car/engine that gets discussed on this board is used the same way. If 180° was some magic number, the modern OEM cars would use it too. Yes, modern cars have to tune for a lot of other things too, but they all make higher hp/cube outputs than these cars ever did stock- they're more powerful and efficient. Sure, the engines discussed here usually aren't stock and don't have smog to worry about, but most of them also don't have nearly the control over their fuel delivery and ignition systems either. Literally no modern cars spec their water temps to be 180°, and a couple dozen degrees of coolant temperature aren't going to hammer your cylinder and exhaust temps so badly that you couldn't deal with meeting the smog and efficiency requirements. Modern OEM's could easily spec a 180° water temp if it made the most power or was the most efficient. They don't, and it's not because they don't know what they're doing.

If you were familiar with other kinds of racing, you'd know that pretty much only drag racing cars keep their engine temps under 180°. There are much crazier and exotic engine builds out there than make gobs of power for a lot longer than drag engines do and do it with much higher coolant temperatures. For a street car, it's not necessary or often even practical to keep the coolant temps between 160° and 180°.

Yeah, that's just BS. Modern cars pretty much ALL run electric fans, and some of them make more horsepower than dirt track cars too. Using a race car as an example is also usually a bad idea, since there are typically specific rules and regulations that require certain things and not others. And pretty much every automotive racing environment is highly specialized, and requires things that don't make sense on a street car. Why dirt track cars run mechanical fans instead of electric I don't know, but it's absolutely not because electric fans aren't capable of cooling those cars.

Don’t be a literalist. :poke::)Packing up, backing up, obstructing, impeding, blocking, restricting, whatever you wanna call it. I posted what I experienced with this Derale:

It wasn’t cheap $$ that’s for sure. Flat plate shroud with high CFM fan. It didn’t take long for me to discover it had to go. You may have known this from the beginning of time, at the time I bought it I had to find an 18 inch fan with shroud that would fit my situation for dragracing and street use. For that it was fine, although I had to run it more than I care to. It was no good for Highway use in my application. And that style is what I am referring to which is the exact same thing you are referring to.

As to your assertion that I said a mechanical fan was “necessary“ maybe you have misread or perhaps you misinterpreted I don’t know, this is exactly what I stated:

12many said
you want as much air flow unimpeded: no flat shroud and/or electric fan that has a bulky blade blocking air flow, a good mechanical fan, (fixed or viscous) as big as you can fit

Re-reading what I typed, it could be you are focusing on the part: “and/or” and perhaps I left out “or” between “blocking airflow, OR a good mechanical......” Was not implying having to use both, no sir. Perhaps I was not as specific and clear as I could have been. Grammatical errors happen.
Instead of seemingly looking to pounce and parse maybe try asking for clarity or simply give the benefit of doubt. No big deal. I know I need to sometimes so, anyway, have a nice evening
:)