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914World.com _ 914World Garage _ air impeller removal and replacement

Posted by: usa4cheer Oct 12 2006, 10:20 PM

i am doing an electric fan conversion and removing the big fan case and was wondering what to for a pulley for the alternator belt with out the fan ... i was looking do free up a little hp from getting rid of the fan part of the pulley

help

Posted by: Mueller Oct 13 2006, 12:42 AM

QUOTE(usa4cheer @ Oct 12 2006, 09:20 PM) *

i am doing an electric fan conversion and removing the big fan case and was wondering what to for a pulley for the alternator belt with out the fan ... i was looking do free up a little hp from getting rid of the fan part of the pulley

help



Type I's (traditional bug motors) use a pulley on the crank, I'm sure you could do the same.


Posted by: DNHunt Oct 13 2006, 07:45 AM

You better consider cooling the alternator also. Remember, there is a vent from the cooling shroud to the back of the alternator. I think many of the newer alternators have cooling fans on the alternator. I think Jake sells a type 1 pulley that mounts to the type IV fan hub as part of his coversion stuff.

As I see that, it moves the pulley aft toward the flywheel a couple of inches so I can't see getting the alternator in it's stock pancake position. It'll be right in the exhaust for #2. Gonna take some real engineering.We need Miles to diagram this. His drafting skills just make things so clear.

Dave

Posted by: davep Oct 13 2006, 10:35 AM

Aside from the fact that electric fans are a poor solution, there is a lot of re-engineering to be done. You could leave the whole fan housing in place to mount the alternator, and remove the blades in the fan to reduce power losses, but keep the pulley on the fan. Block off the flow to the engine, and if anything is left it may cool the alternator.

You don't want to cook the alternator. You will need a more powerful alternator just to run the fans. Running the alternator to run the fans is a much larger parasitic loss of power than the crank mounted fan. So expect less acceleration, and be prepared to spend big bucks on a big alternator.

Posted by: Mueller Oct 13 2006, 12:58 PM

on this setup, the alt. is turned around....

IPB Image

Posted by: bottomend Oct 13 2006, 08:33 PM

Jake did all the cooling research a couple of years ago and he remardked on this and many other set ups. It's best to get over to the shop talk forums and start looking through the archives of the T4 and Air Cooled tech forums.

Posted by: usa4cheer Oct 13 2006, 09:11 PM

I am only using the car for autocross and not too worried about a big heat build up, because of the short runs, i have a hose going to the alternator vent.
i will check with jake too.
thanks
tim

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