Anyone make a plastic 11 blade fan?

[EarlyPorsche]

I wouldn't mind having a lighter plastic 11 blade fan. Is that an option?

[Tyson Schmidt]

I wonder if it would stand up to the pressure. That fan moves a TON of air. And there is a lot of resistance on the other side. I've seen engine shrouds that were missing a few bolts in the rerar, and the shoud flexed a good 3 inches off the motor when revved.

The mag fan is plenty light, IMO.


If you really want to save weight here, I've found the later carrera alternators are significantly heavier than the early ones. That's also some rotating mass too.

[Early_S_Man]

Porsche has always used FRP fans [fiberglass-reinforced plastic] in horizontal applications for racing engines since the days of the 771 engine ... but, I suspect that long-term durability was never a concern. Looks neat, though, in the engine pics of RS61s, 804s, 907s, 917s, and 935s.

[vanwyk4257]

I would think something with Kevlar reinforcement, or possibly carbon fiber with a strong weave would be up to the task even at higher revs, but the cost to accurately produce a part like that would be astronomical!

[EarlyPorsche]

Most new cars have plastic fans. No kevlar or carbon fiber involved.

[Rearden]

Originally posted by EarlyPorsche
Most new cars have plastic fans. No kevlar or carbon fiber involved.

Yes, but a plastic fan attached to a radiator or oil cooler is not in the same league as a 911 fan sucking air into the dark recesses of the motor.

[Porschekid962]

Call up PMNA and get your hands on an IMSA 962 fan in carbon kevlar. I saw a setup like that not too long ago at PMNA. I believe the housing is also a bit smaller than normal as well.

[RickM]

I spoke to a friend in the plastic injection molding business about this application. He said it could be done but the mold and low volume production would be very expensive.

[Wayne 962]

Originally posted by Tyson Schmidt
I wonder if it would stand up to the pressure.

The 917 ones were plastic (fiberglass)...

-Wayne

[IROC]

Originally posted by Tyson Schmidt
If you really want to save weight here, I've found the later carrera alternators are significantly heavier than the early ones. That's also some rotating mass too.

No doubt. I just replaced the alternator in the '88 3.2 in my car and it was as if I was mounting a shot put back there. Very heavy.

Mike

[David]

Carbon fiber would be nice. With the lower weight, imbalance wouldn't be as much of an issue so maybe balancing wouldn't be required.