how much cooling from different fans? 84 280e
 

on my autocrosser, i would like to eleminate the weight of either the electric auxiliary fan or the mechanical one with the clutch. does anybody know how much cooling each affords? i would want to keep the one which does more cooling.

logic says to me that the mechanical fan does a lot more by the size of the blades etc.

tom w

Using an electric cooling fan CAN allow the engine to produce 5-6 more HP than the clutch style fan & still provide adequate cooling.

...plus electric is full speed airflow at idle/low rpm..

^Did this on my 2.3. Went with an aftermarket electrical fan. I was sick and tired of sitting in hot traffic and watching the needle creep above 100, because the clutch was locked to the engine it was dependent on engine speed so the temp would remain a little high until traffic cleared and the engine picked up speed to give the fan full air flow. Also when locked the fan took a lot of power away and with a 2.3 you need all the power you can get ;)

thanks for the responses, guys.

the fan i presently have on there is the one that is for the auxiliary for when the ac is working.

is that big enough to cool the engine?

tom w

When I autocrossed in a Saab, I had a switch on the dashboard to override the electrical fan and turn it on. It was also illuminated to tell me when the fan was running (due to that switch or the water temperature sensor).

You don't need the fan during the run for Solo-II, but as soon as you start to slow down, all that heat has to go somewhere so turning the fan on then did a very good job.

see, now the saab has only the electric fan, right? so it is designed to cool the car.

in my car the fan is not designed for cooling the car just is an auxiliary for use when the ac is on.

i suppose rather than hound folks about it i should just rig a switch on it and remove the mechanical fan and give it a try.

tom w

Yes, the Saab had the engine reversed (belt against the firewall) and only an electric fan. But if you lose the belt-driven fan, you may be able to fit an additional electric fan behind the radiator, if you need one.

I wouldn't worry very much about the weight of an electric fan. I'd worry more about the load on the crank of the mechanical fan (or the alternator, if the fans are running before you need them).

The problem with the aux fan is it is pushing airflow through the a/c condenser , but by the time it get through the cond and radiator , there is not a lot of force left for engine airflow. A better set-up would be a puller fan behind the radiator with a fan shroud.........

i would take the condensor out.

i am not sure if there is room for a puller fan behind the radiator. do you think there is?

tom w

Take a look... if you remove the cond, then you may get away with the aux fan..try it.

Pushing or pulling, you have the same restriction. I don't think that's an issue.

There may be room behind the radiator, if you position it carefully and there is no mechanical fan in the way.

The restriction to airflow volume from a pusher and a puller are different b/c a pusher fan causes airflow turbulance when the air hits the fins/tubes under pressure , whereas a puller does not..there is a big difference in airflow patterns between the two.
The problem with a puller is it has to have a shroud b/c it will attemp to pull supply air from outside the fans circumference, circumventing core flow...but the shroud makes the air supply travel threw the core.

I put an electric fan on the 85 a couple years ago with the idea that
when in hot weather, like 115 in Phoenix with the AC on, I wanted to
be cool:cool5:. the stock fan doesn`t cut it when in traffic, and the engine
is at slow speeds. the temp quickly rises to almost melt down.
so I removed the fan, put the bolts back into the pully, and installed a
16 inch electric I got on E-bay. It was listed as pulling 3300 CFM of air.
but the damn thing is starting to crap out, the bearing in the center is
shot and the fan in wobbling in the cage, still works but doesn`t move
enough air. Don`t buy a Zirgo fan cheap junk.
I just bought a different one yesterday at the Good=Guys street rod show
from one of the vendors. it`sfrom RB`s Obsolete Automotive, they deal
in 55, 56 57 Chevy etc.. streetrods with pumped up power. they are located in Glendale, Az. this one was $139.95 and will blow your wig off.
you will deffinately want a puller type fan, work much better. there is
plenty ao space between the radiator and the pully. this one shows 3.39 inches deep, and a 16 inch. 2360 CFM. the brand on this is a SPAL.
they also list one that moves 3000 CFM, and is $239.00.
Hope I helped some here.
Charlie
.
Charlie

that sounds pretty nice.

i will have to think about it. my conditions should not be as severe as yours in az (is it?), but on a hot day the heat will build up on repetitive runs so i do need good capacity to cool.

how much does the street roddder radiator weigh?

thanks for all the posts on this fairly obscure thread.

tom w