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View Full Version : fan blade drag and fuel pump drag?



dmstang
05-05-2011, 11:24 PM
Currently I'm using 6 blade flex fan and I'm thinking it's too much of a drag on the engine. I believe rules allow electric fan, would it make any difference if I used electric fan?

I also use stock fuel pump and the rules allow electric pump, would it also make any difference if I switch to electric fuel pump?

I would like to get the most out of my engine and I don't have any access to dyno so it's all guess work here.

Thanks for your help

longhornracer
05-06-2011, 01:34 AM
fuel pump wont make any diff in power. I have always ran a flex fan myself but the more weight you get off that motor the more power you get even if it is minimal

drtlvr
05-06-2011, 05:15 AM
I've ran electric pump and fan and switched to a nylon fan and mechanical pump. I can't tell a difference, just cheaper!

84Dave
05-06-2011, 08:22 AM
At 100% efficiency, 746 WATTS = 1 HP. P(watts) = I(amps) x E(volts). Our 6-blade, 16" electric fan @ the back of the radiator pulls 11 amps running full blast. Our alternator output is 14 volts. So...... P=IE is 154 WATTS to run the fan. And 154/746 = .206 HP to run the fan. Most electric fuel pumps require 4-5 amps to run 'em. That equates to slightly less than .1 HP to spin the fuel pump. A 4-stage dry-sump oil pump requires right at 2 HP to turn it @ max rpm. A wet-sump oil pump, much less. It requires MUCH more HP to spin the tranny/rear-end than all the above combined! -Dave-

rtcaldwell
05-11-2011, 06:48 AM
Any Nylon fan will work or is the water pump some oddball bolt pattern?