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Expert 5K+
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| obviously if you don't care about keeping its 100% stock... this won't do but its alot of horsepower. https://www.youtube.com/embed/ZXdLgaFXZzs
Edited by mikes2nd 2017-05-03 11:14 PM
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Expert 5K+
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Location: So. Cal | Installing an electric fan is a big change, as they say, but you can get half that power back 15hp just by installing a clutch fan. That is a pretty good compromise that doesn't require a lot of blatant changes. But the stock 4 blade fans probably don't draw that much power, and they don't cool as well. |
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Location: Houston | and where do you suppose the power to spin that fan comes from....? |
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Location: Lower Mainland BC | GregCon - 2017-05-04 9:15 AM
and where do you suppose the power to spin that fan comes from....?
Would it be that pathetic 30 AMP generator that is driven off the crank by the *FAN* belt(s)?
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Expert 5K+
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Location: So. Cal | Exactly. It requires a lot of changes, including a powerful alternator, relays, upgraded wiring, radiator mounts, ammeter bypass or .....etc. The power to drive an electric fan is minimal as they state, it is only 15 Amps at 12 volts = 180 Watts = 0.24 hp. Practically nothing in comparison. There is also an efficiency hit from the alternator, but that isn't much either. |
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| what he said ^
Edited by mikes2nd 2017-05-04 10:17 AM
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Location: NorCal | Powerflite - 2017-05-04 7:08 AM
The power to drive an electric fan is minimal as they state, it is only 15 Amps at 12 volts.
Kinda depends on the fan doesn't it? I have three cars with hi-output alternators and aftermarket electric fans, on each of them I can tell when the fan is running by looking at the tach.....when the fan first comes on there is a noticeable drop in rpm due to the fan's starting load and the rpm stays lower than normal until the fan cycles off. Fan running load is advertised at 20 amps.
Not a very scientific observation but it tells me the fan's load on the alternator is a noticeable horsepower draw.
Edited by 57chizler 2017-05-04 1:12 PM
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Board Moderator & Exner Expert 10K+
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Location: Southern Sweden - Sturkö island | Perpetuum mobiles doesn't exist in reallity.  |
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| They left out the CFM flow of each fan. Some engines need more flow than others. Air conditioning will increase needed cooling, So will increasing power output of an engine.
Its all part of balancing your system if you are going to change the stock components. A clutch-less fan is far from ideal but is reliable virtually indefinitely versus a clutched fan.
How much air flow do you need to keep that temp needle from ever moving once your engine is warm? That of course is a more in depth and informative experiment versus what these guys did.
At least what they gave is some valuable info for a starting point for anyone interested in changing fans.
Electric fans is sort of out of the question for FL cars unless you are willing to do the above listed changes.
Purpose build for your application. Modify or upgrade accordingly. Knowing the drawbacks before doing mods is great knowledge.
If you just cruise around mildly I wouldn't worry too much as long as your temp needle is steady once warm.
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Location: NorCal |
Since all of the FL years are stuck with the 22" radiator, A/C can become the deciding factor. In later years they went to a 26" radiator when extra heat load was added.
Before I added A/C, temp would stay at the middle of the gauge at idle with a 17" rigid fan regardless of the OAT...after the A/C install I needed the electric fan to maintain the same temp. |
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| http://www.speedwaymotors.com/Speedway-Double-Pass-Aluminum-Radiator-Chevy,23864.html https://www.radiatorexpress.com/product.asp?part_id=221058&aaia_id=1228643 there are many 22 inch radiator option it looks like. |
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Elite Veteran
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Location: Oley, PA | Just a quick reality check on this test. The final test they performed (with the fan shroud removed) is probably the most relevant to Forward Look cars. None of my FL cars have ever had a fan shroud. In this test, the horsepower reduction they observed was 22.3 HP, not 30. And that of course was at maximum RPM. At lower RPM, the loss is proportionally less.
I was a little surprised that they appeared to be baffled by results of the unshrouded test. It's not rocket science. The shroud provides a restriction on the air flow path, ensuring that a higher percentage of air is drawn axially through the radiator as opposed to radially around the engine compartment. This path has a higher resistance to airflow and thus more parasitic loss (the fan has to work harder).
To make the test accurate, they really should have tested it with the alternator installed and electric fan. While the calculated draw from electric fan appears small, it still assumes 100% efficiency of the system, which is probably a bad assumption. The mechanical power required to drive a generator is always higher than electrical output produced. It would be interesting to know the actual numbers.
Finally, a real-world test would include the effects of ram air flow through the radiator at highway speed. I would think this air flow would provide some windmill effect on the fan, assisting the direction of rotation, and thus relieving some of the parasitic drag on the engine. How much? I have no idea.
While 22.3 horse power is not insignificant on the top end, I believe to the typical FL driver, the impact would be barely noticeable. In short, it would be a lot of work to achieve a minimal benefit. Could definitely be worthwhile if you are racing but otherwise probably not worth the effort involved.
Edited by Greg P. 2017-05-18 11:36 AM
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want to make 30 horsepower?
