anyone know the CFM our blet driven fan pulls?
05-27-2006, 02:20 PM
#31
Rennlist Member
probably not, especially since the aftermarket world is generally not that smart. remember these are the guys that "claim" mileage gain when you use their air filters. (power yes, MPG no) also, remember, 1hp is at max flow, which by design of the fan and clutch happens in the higher rpm range ,and is near 3500rpm according to the porsche 928 specs. any slower rpms and the HP required to drive the fan goes down by a factor of 8 when we are talking about the difference between 1700rpm and the max fan rpm of 3500rpm.
I think you got the right idea, when the driven fan is cooked, electric is a nice change, plus, it sure makes the big jobs easier on the front of the engine with out it, plus, you can hear the engine better as you just mentioned.
for me it was a little of both, and certainly, if its 1hp of drag, thats 1hp i can use in racing. 1hp for the cost of a relay and a electric fan is a pretty good deal.
Mk
I think you got the right idea, when the driven fan is cooked, electric is a nice change, plus, it sure makes the big jobs easier on the front of the engine with out it, plus, you can hear the engine better as you just mentioned.
for me it was a little of both, and certainly, if its 1hp of drag, thats 1hp i can use in racing. 1hp for the cost of a relay and a electric fan is a pretty good deal.
Mk
Originally Posted by Imo000
Well, maybe the total gain that the aftermarket claims is, overall area gained under the HP curve. Perhaps possible thats where the 5-10hp gain is calculated from?
On mine the bearings were shot and that was the main reason for the switch. 6 months later I build a supercharger system so at that point it would have been necesarry to switch for an electric fan anyways. The airpump had to be removed to make room for the supercharger head unit.
With the original fan, the engine had a " large displacement" sound. If was the fan making all the moise. After the switch I can hear the individual injectrors slightly ticking away. With the electric fan its much easier to listen to the engine tp make sure everything sounds right.
On mine the bearings were shot and that was the main reason for the switch. 6 months later I build a supercharger system so at that point it would have been necesarry to switch for an electric fan anyways. The airpump had to be removed to make room for the supercharger head unit.
With the original fan, the engine had a " large displacement" sound. If was the fan making all the moise. After the switch I can hear the individual injectrors slightly ticking away. With the electric fan its much easier to listen to the engine tp make sure everything sounds right.
