Cooling fan HP losses...

[cjshaker]

I know this is pretty common knowledge, and that many of you watch Motor Trends' Engine Master videos and have probably already seen the latest one about cooling fans, but just thought I'd throw this out there for those that don't.

It really kind of drove it home just HOW much power you're giving up by using a standard cooling fan. Even the best type, the clutch fan, which I had considered going to, gave up over 20 HP. The "high performance" fans were even worse, robbing as much as 31 HP. It's hard to ignore this fact and I'm now considering switching over to electric. Can't say I'm a 'fan' (pun intended ) of adding more weight and more complex wiring, not to mention having to switch over to the 3G alternator, but to ignore the HP gains seems stupid. Who wouldn't want an extra 30 HP without even having to touch your engine?

I like simple mechanical designs. Very little to go wrong and much easier to work on, but I think I'll take a little stroll on the Dark Side...
Has anyone had a direct comparison to ET gained from switching from mechanical to electric?

The link to the Engine Masters video for anyone wanting to watch it...
https://youtu.be/ZXdLgaFXZzs

[chilly460]

Car Craft did the same type test a LONG time ago, and came up with similar results.   I'm usually a "simpler is better" guy as well, but hard to pass up the benefits, plus no fan to worry about cutting off a thumb while you're working on a running engine.  I run a simple 1 wire 100amp alternator and it runs my fan OK. 

[machoneman]

I respectfully disagree. Below is the old CC fan test and it clearly shows only a 7.7 hp non-thermal STD clutch fan loss to an electric fan.

http://www.network54.com/Forum/215655/message/1066184641/Car+Craft+Cooling+Fan+Dyno+Test

My '70 Mach 1 (490 hp worked 358 CID Windsor) has the same set-up, reliable as all get out. I can live with the reliability for only a small hp loss.

I know this is pretty common knowledge, and that many of you watch Motor Trends' Engine Master videos and have probably already seen the latest one about cooling fans, but just thought I'd throw this out there for those that don't.

It really kind of drove it home just HOW much power you're giving up by using a standard cooling fan. Even the best type, the clutch fan, which I had considered going to, gave up over 20 HP. The "high performance" fans were even worse, robbing as much as 31 HP. It's hard to ignore this fact and I'm now considering switching over to electric. Can't say I'm a 'fan' (pun intended ) of adding more weight and more complex wiring, not to mention having to switch over to the 3G alternator, but to ignore the HP gains seems stupid. Who wouldn't want an extra 30 HP without even having to touch your engine?

I like simple mechanical designs. Very little to go wrong and much easier to work on, but I think I'll take a little stroll on the Dark Side...
Has anyone had a direct comparison to ET gained from switching from mechanical to electric?

The link to the Engine Masters video for anyone wanting to watch it...
https://youtu.be/ZXdLgaFXZzs

I know this is pretty common knowledge, and that many of you watch Motor Trends' Engine Master videos and have probably already seen the latest one about cooling fans, but just thought I'd throw this out there for those that don't.

It really kind of drove it home just HOW much power you're giving up by using a standard cooling fan. Even the best type, the clutch fan, which I had considered going to, gave up over 20 HP. The "high performance" fans were even worse, robbing as much as 31 HP. It's hard to ignore this fact and I'm now considering switching over to electric. Can't say I'm a 'fan' (pun intended ) of adding more weight and more complex wiring, not to mention having to switch over to the 3G alternator, but to ignore the HP gains seems stupid. Who wouldn't want an extra 30 HP without even having to touch your engine?

I like simple mechanical designs. Very little to go wrong and much easier to work on, but I think I'll take a little stroll on the Dark Side...
Has anyone had a direct comparison to ET gained from switching from mechanical to electric?

The link to the Engine Masters video for anyone wanting to watch it...
https://youtu.be/ZXdLgaFXZzs

[chilly460]

Thats assuming the Car Craft test is the accurate one....

Either way, 10-20hp through a wide RPM range, with something as simple as reducing parasitic drag seems like a good update. 

All depends on priorities of course, if a guy isn't trying to optimize his combo it's not a big deal.  Any vehicle built in the last 10-15yrs has an electric fan so not sure what the issue is with reliability. 

[Falcon67]

I use electric fans on everything - got tired of dodging the 16"~18" salad shooter engine driven stainless blades.  A also engineer the radiator/fan setup as a unit.  In most cases, a couple of bolts and disconnecting a plug allows the entire assembly to lift out of the car for front motor work.  Combined with a quality electric water pump it frees up space and reduces power loss.  Add in my preference for electric fuel pumps too.  You get to where the whole motor including alternator is assembled on the stand, then drop in, connect a couple of  harness plugs and a few wires, connect fuel line, bolt on headers, drop in radiator assembly and done under the hood. 

[Heo]

Im that kind of guy to  why put on more electric stuf ?
But 30 hp, even if you dont are after those last extra
horses,they burns a lot of gas those 30 horses

[chris401]

As for modern car fan donors I personaly have not seen many problems with the Ford Taurus compared to Jeep being the most problematic. If you drive your vehicle more than 3000 miles a year you may come out ahead buying a new fan and switch from Ford, if you can still get them.

[rcodecj]

I run two Spal electric fans, one 11" and one 12 " on my 67.
They are pusher fans which I know is not as good as puller but they cool fine in AZ summer heat.
It sure is nice to work on with all that room.
It's been around 10 years and they've been reliable but I can't say I drive a lot of miles.

Now for the electric fan hp loss I ran back to back 1/4 mile passes with and without the fans turned on and
found no discernable difference in the ET's. The car was very consistent ET wise so I believe the results.

[NIsaacs]

Usually an engine driven fan is bolted to a mechanical water pump, so you need to consider both. I always figured a water pump with a closed thermostat used more power than a fan.

Nick

[machoneman]

Yes, the really hot set-up would be an electric water pump and electric fans. But I've  not seen a current back-to-back test of same. Anyone here have any test article to post up?

[cjshaker]

I respectfully disagree. Below is the old CC fan test and it clearly shows only a 7.7 hp non-thermal STD clutch fan loss to an electric fan.

Bob, I would think that Steve Brule has some of the best equipment available for testing. I would guess that their dynos are modern and pretty darned accurate, so I'd be inclined to believe their testing, but admittedly they didn't test a non-thermal fan either. I really do prefer simple and reliable, but because I'll be switching to an electric pump, I'll basically have no choice. But I'll admit that not having to fear for my hands and fingers is pretty appealing also.

Combined with a quality electric water pump it frees up space and reduces power loss.  Add in my preference for electric fuel pumps too.

Chris, that's the thing. I bought a set of Jays' water pump adapters and am planning on switching to a CVR water pump, which would necessitate an electric fan. For the money, I think it's about the cheapest horsepower upgrade one could do. With the O-ring seals on Jays' adapters, it's also appealing for the easy access to the front of the engine without having to deal with gaskets every time.

[jayb]

My dyno test, with a fixed blade aluminum fan and an Edelbrock pump vs. an electric fan and the CVR pump showed a difference of about 20 HP at 5500 RPM.  Almost no HP change up to 3500 RPM, but then it starts and grows with RPM.  I could easily see a 30 HP improvement if you were spinning the engine to 6500+.  Another point of reference might be what I read somewhere a long time ago, about the mechanical water pump on the SOHC.  It was said that cooling systems pressures of up to 90 psi were recorded at 7500 RPM at some point in the cooling system for those engines.  For the pump to develop that much pressure in a recirculating system, you know it was taking some power...

[machoneman]

Thanks Jay as we now have a good point of reference. I do wonder though what the net would have been with a non-thermal OEM type clutch fan and the electric pump. Maybe someday.....................

[Katz427]

Just to back up Jay's testing with the "Fan laws" as stated volume increases directly with rpm. Double the rpm = double the flow. Static pressure goes up by the square. The hp required goes up by the cube. So if the fan was consuming 3 hp at 3500 rpm then at 7000 rpm that should be 27 hp. Of course this assumes the fan is not in stall. The "laws" work for centrigual pumps as well. So if the pump is generating 10 psi in the system at 3500 rpm then at 7000 rpm it would generate 100 psi.

[cjshaker]

I suppose that that info was in your book, but there's so much info in there that it tends to get lost in my memory

I recall Blair talking about water pressures with standard pumps on high RPM engines and that had crossed my mind also.