Does anyone recall a post on the technique of alterning the impeller shroud to improve air flow over the cylinders. I can't seem to find it.
I removed every other on my impeller. Hope it improves the flow.
Thanks.
L. McC

I hope you took it to the machine shop and had it "zero" balanced afterwards. If not, you might have a vibration in the motor.

I didn't do mine that way but yours looks good. I hope I removed more blades. Will post a pic later.

How did you remove your blades? I used a dremel to cut the base of the blade and then snapped them off with pliers. Then I ground down the stubs with grinder bit.

I hope the damn thing balances up.

Not sure about shroud mods. We are going to be using a vanagon shroud for the race motor. Since we don't run an alternator, we can use it. Supposed to cool better.

dr

Synthesisdv, yes. Dramels are great. Got to HD cutting wheel, and cut 4/5th of the base. Then snapped them off and filed down the remainder.
Slits, working on the pulley now and will then spin/balance. From your statement, is balancing done by removal of base where fins have been removed?
L. McC

Is the idea of removing the vanes to improve airflow at high RPM? If it flows more air with fewer vanes, why wouldn't they have shipped it that way from the factory?

I woulds assume they would use a drill to remove metal in the outer housing to bring it back into balance after spinning it up on a balance machine. The fan would be a sort of "harmonic balancer".

well the factory knew a thing or 2 but they designed the fan but they had in mind a much lower average operating rpm, like 4500.

our motor will live between 5000 and 7000 rpm where the stock fan would cavitate, so removing blades helps flow and lessens the parasitic losses.

Regarding balancing, the fan is anything but a harmonic damper, Jake says the fan makes the rotating assy very hard to balance.

dr