Power savings from Electric water pumps and fans: real or imaginary

[CDMBill]

There have been a number of threads that have dealt with this topic over the llast year or two here on Bangshift in this Tech section and in the Drag Week section. One of the now legendary Drag Week participants, Jay Brown decided to settle the issue in his own inimitable style by testing it out on his own dyno with his test mule 428 Cobra Jet. He has been kind enough to publich the results on the FE Power Forum and I thought it was worth noting here on BS.

He found 20 HP right across the board and he also has a link to the now legendary Car Craft article that found 40+. Lots to read and digest.

See link below.

http://fepower.net/simplemachinesforum/index.php?topic=959.15

[Orange65]

Interesting. I may be on the way to change my mind to run an electric water pump. I currently run an Edelbrock HV mechanical with no fan- he picked up roughly 10 HP over that with an electric pump. Hmmmmm....

[mlcraven]

Saw Jay's results as well. I'm planning to stay with the orig. equipment clutch fan that came in the Cyclone.

[squirrel]

Interesting, but it doesn't really tell us how much HP a mechanical fan uses when you are drag racing. Cars move, dynos don't move. So, the fan will be doing very little work once you get the car moving, and probably take less HP to turn.

If you want to get serious about all of this, you'll get a pwm speed control setup on your electric pump and fan, with a pid loop based on coolant temps at certain places in the cooling system.

[MR P-BODY]

There have been a number of threads that have dealt with this topic over the llast year or two here on Bangshift in this Tech section and in the Drag Week section. One of the now legendary Drag Week participants, Jay Brown decided to settle the issue in his own inimitable style by testing it out on his own dyno with his test mule 428 Cobra Jet. He has been kind enough to publich the results on the FE Power Forum and I thought it was worth noting here on BS.

He found 20 HP right across the board and he also has a link to the now legendary Car Craft article that found 40+. Lots to read and digest.

See link below.

http://fepower.net/simplemachinesfor...p?topic=959.15

I find his results HIGH... I/Chrysler did this test in a wind tunnel when we were changing over
to different pumps and fans... the pump alone was 6hp, the fan had differentiating results based
on temp(clutch fan) but it could be 11hp... then you have belt drag ... was his alt still hooked up
during the testing or did he drop that also.... so if you add up the alt, belt drag, fan and pump it
could be up in the 20+ hp range... but to just say the pump... his numbers are way high .. all the
data I state was on a stock production engine

[quick 52]

i use a dodge viper cooling fan it draws over 30amps on start up and will slow my rpms about 200rpm when it come on dont know what hp is but was supprised at the rpm drop

[Aircooled]

Interesting, but it doesn't really tell us how much HP a mechanical fan uses when you are drag racing. Cars move, dynos don't move. So, the fan will be doing very little work once you get the car moving, and probably take less HP to turn.

If you want to get serious about all of this, you'll get a pwm speed control setup on your electric pump and fan, with a pid loop based on coolant temps at certain places in the cooling system.

Good point about the moving vehicle reducing the fan HP draw. However, this HP reduction will be linear with vehicle speed and the fan's HP consumption will be rise to the cube of engine speed. So at redline in first gear, the in-car HP consumption of a mechanical fan is going to be very close to the Dyno number, while at the bottom of your top gear for the 1/4 mile, the HP consumption would be less than the dyno number for that RPM. The invention of the flex fan was an effort to dial back the cubic HP increase to something closer to linear. It would be interesting to test how close to linear the flex fan gets.