Which cooling fan should you run on your Buick 350?

...or any other engine for that matter.

Here's a video from Engine Masters showing the parasitic loss from various cooling fans that may come as a surprise:

 

I'm using electric fans

 

Factory clutch fan for me

 

Apparently I have the crappiest HP killing fan possible...awesome!

 

Tried aluminum and plastic flex fans in the 70's, didn't like them at all. Took them off and went back to clutch style.

IIRC, they were noisy and had substandard cooling.

 

The importance of parasitic loss is not to be ignored, for sure.

Compare the numbers, proven on a dyno in the video, to parasitic loss figures from other components, such as transmissions, other accessories, etc. and the reality of Net power becomes very clear.

Who'd have thought so much was lost from just the fan?

 

Did you guys notice the motor put out 349 hp and 409 TQ no more than the Buick put out in the other thread, you know the one with the 600 carb on it. The Chevy has alum heads with headers all the good parts the we do not have....yet. So I do not know why anyone would complain about having 320 hp and 410 tq from the Buick 350 motor. You also see what looks like a dbl pump carb maybe a 750. It also has what looks like the best dp intake there.

The one Jim did with the 212 cam had just about 350 hp and what 410 tq.

So don't be so disappointed in your Buick ONLY making 350 hp and 410 ft lbs of tq. as in the other thread.

looks like the clutch fan is the winner which is what I thought or the best is to use the elec. fans and get your 15 back.

 

Stock GM mechanical fan with clutch, plus a slimline electric helper fan hidden inside the shroud

 

What would I look for if I want to replace my fixed fan (5 blade 350 non air) with a clutch fan?

 

Mine is an original clutch fan and is 7 blade. I had air conditioning in my car. If you can find any 350 that had air conditioning there is probably a clutch fan with a 7 blade fan attached and you can use that. You might need the pulley that goes with it but most likely not. You may need a shroud if you do not have one on there now, that part may be hard to find Maybe at OPG or Year One they may sell them. Junkyard one will be hard to find.

 

couple things to note about this video. first - the pulley ratio looks to be almost 1:1. the fan might is probably slightly overdriven. most factory setups overdrive the water pump almost 2:1. i would wager in the real world most of those fans would use more power.

second- the clutch fan was in a cold shroud. it certainly wouldn't be engaged. those numbers would only be accurate when the fan is disengaged. it would likely be as bad as the factory fixed fan once it was engaged.

third- the faster the car is moving the more ambient air (cfm) going through the radiator. as your vehicle speed increases the cfm of the air moving through the radiator increases. that greatly lightens the load on the fan and reduces hp robbed. at some point even the ambient air cfm being forced through the radiator would be equal to what the fan is pulling and the mechanical fan would use very little horsepower. maybe 60-70 mph.


food for thought..

 

Excellent points.

 

I run a mechanical clutch type fan now, but when I bought my car it had one of the aluminum flex fans and it never cooled very well and looked like crap imho. Didn't fit in my shroud right. I'm a huge fan of Engine Masters (and Roadkill) but in this test they only talked about the power loss and not about the cooling benefits of each type.

I've been lead to believe that mechanical clutch type fans are a good balance between power loss and good cooling, so for a daily like my car I thought it was a good choice that didn't cost too much.

 

I think it's a no brainer to go to an electric fan... Less Hp loss and mine cools fine.

 

The only reason to go electric in my opinion is packaging.
If you have no room for a mechanical fan, then try to squeeze in an electric.
OR, if your after every last bit of HP, don't run a fan at all, just keep the car moving fast enough to move air across the rad.
Even electric fans use HP to run in the form of electrical load on the UPGRADED alternator

 

I think the electric fan's load was mentioned in the video costing around 1 whole hp or so.

I also think that 15-30 hp lost at slower speeds where there's less air moving through the radiator is pretty significant and is worth the swap over to electric if one can afford it.

The dyno also shows that the higher the engine revs, the more power the fan takes to turn, and they only revved the test engine to 5200 rpm or so.

At the drag strip with more radical engines, the power loss would be so significant that your 60' times (and probably half way through the quarter) would be noticeably and adversely affected.

The power loss would be akin to taking your headers off and putting the iron manifolds back on. I don't think anyone's willing to do that (unless you were already using them for whatever reason(s)), so why try to talk yourself into thinking that the fan you're using now isn't really worth the swap over to electric fans?

 

I would bet that the fan spinning at 6 grand along with trying to push thru the wind at 80 mph will cost a bunch of hp.

I would bet that water pump costs some ponies too. Could use a electric pump for that also. But what would use more hp, the elec water pump or the water pump itself.

Then you have to worry about those two elec item not working for whatever odd reason, usually on the hottest day of the year your elec fans go out, or that elec water pump dies.

What about the elec fuel pump how much does that cost in power electrically or mechanically.

So, if you hooked up all 3 of these electrically would this cost you more HP at the alternator or would the all 3 mechanical items cost more hp off the motor? Using the clutch fan of course, but remember when it is hot out the clutch fan is going to lock up more than on a cooler day.

 

I think this all comes down to what kind of car and budget you have, like everything else haha. If you're driving your car on the street all the time, the peace of mind (less likely to break) and decent cooling plus low cost that a mechanical fan provides is nice. But I agree with Gary; if you're trying to shave your ETs down and aren't as worried about cost or day to day reliability then electric seems to be the way to go. Well I don't really know if electric fans are less reliable because I've never run one.

Anyone on here daily their car with electric fans?

 

All front wheel drive cars that I know of use electric fans and they do just fine with those.

I'd say they're pretty reliable.

How long does a clutch last on a mechanical clutch fan? I've had those go bad before.

Is anything immune to wearing out?

As far as cost goes...no one seems to be scoffing at buying other race parts that make their car go faster, so....?

If 30 hp is meaningless, then might as well take out those lumpy cams everyone loves to go on and on about, since that's about all they're giving over the wimpy stock cam, or drop your compression from 10:1 to 8:1, that should make about 30 hp or so on a mild engine. I already mentioned the headers vs manifolds. Is there another example I could use that might put it into a better perspective?

Could there be a simpler way to gain 30 hp?