Yeah, it's a big loss, but it doesn't bother me that much. I'm fine using my clutch fan until I can get an electric setup I like.
Anyone Feel Like Running a Mechanical Fan?
- Thread starter motorheadmike
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I had that fan factory on my 70S, 350, non A/C with no shroud. Foxtrot on here used that one with his 403, it does move a lot of air. Interesting that it draws less power than some.they didn't rate this one but it's one that racers use and it takes less hp to spin it but it does move alot of air...
Any of the lower HP draw "flex" fans do this. Most aren't stalling, they are going flat. Another reason why a mechanical fan is completely stupid on a performance car.
My 2+2 originally had 3.50 gears and was overheating at 120 mph at 5000 RPM at the Big Bend Open Road race in 2003 and I was barely giving it gas (120 mph takes less than 180 Hp of the 500 available). I didn't want to break 6th gear again in my Richmond, so I had to rev it high in 1:1 5th, and the "fast" spinning fan was flattening and blocking the air.
An electric fan will NEVER do this. We switched to electric fans and changed the rear gears to 2.50's and could run all day at 168 mph and 5700 with the motor @ 200 degrees.
We went from Overheating and barely averaging 115 mph in 2003 to getting second in the 135mph average class to a 2004 Porsche GT3 by .016 Seconds (.001 mph after 118 miles) in 2004, and placed 5th overall out of 115 cars.
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That fan does move lots of air!
The SBO 403 is a tough engine to cool as most classic Olds guys know. With the old stock mechanical fan, I would observe 'temperature stacking' while in traffic and during other situations. With the four blade fan shown above, the engine can actually be kept within my desired temperature range.
I know that as far as performance goes, the electric fans are the way to go. My car is all old school tech and just utilized as a weekend cruiser that doesn't see the track. Not a performance machine as far as today's technology and for this reason, the mechanical fan is just fine.
Not to beat a dead horse, but this Article from 17 years ago is used by mechanical fan guys to believe they get more "CFM" than electric fans and therefore justifying their 115 year old fan design.
The electric fan in the article, described as "the most powerful electric fan available" is a singe 15" fan, because $120, brand new Dual 14" fans were still a year off from when the article was written in 2000 (or didn't advertise in Carcraft and therefore didn't exist).
A Dual 14" fan on 12 volts with flow more air than a mechanical either at Idle or at speed (because you can't have both with a mechanical fan and NOT LOSE 30 HP). Unclutched mechanical fans designed to flow a lot of air at idle, go flat at speed, blocking airflow. If they don't go flat, they eat HP. Clutched fans are not designed for high HP/high RPM applications - the Clutch can't take it and will fail pretty rapidly.
When you hear a guy blah blahing at a car show about how his car "will go 160", check his fan. If its mechanical, he can do 140 for about 1 mile before the car starts to overheat. After about 10 miles it will be above 240 degrees if he keeps it above 130 mph.
Pro Criminal tip #57: Don't try to run from the police with a mechanical fan.
UNGN - Just curious if you ever tried running w/o a fan for your type of racing? I know the electric fan is probably being driven at your speeds. Also does anyone run methanol? I know the big disadvantage would be how much you would have to carry. Would love to ride shot gun on one of those passes.
The problem with no fan is that open road race starts involve 140 cars lined up single file, leaving at one minute intervals, usually in 90+ degree heat. A car without a fan would overheat before it got to the starting line.
There are a few people running methanol in open road racing. The most notable is a guy from North Dakota who ran a '62 Polara for years with a big block and a homemade methanol injection setup. It was fast, but I think he has over 40 gallons of fuel onboard to run 100 miles and even then has run out of gas on course before.
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