Spinning Vortec SC

[gerry_miranda]

Took out my SC belt today. I was wondering how hard it is to spin the blower by hand.

How much rsistance is the blower suppose to have?

I can spin it by hand by turning the pulley BOLT. After I let it go, it will free spin about 1/4 of a turn then stop.

It certainly not like my old turbo, where spinning the impler will free spin forever.

Is that about right?

[Jd886]

If thinking about it logicaly, you'd want to have no resistance. Becuase if there is resistance, than the turbine can't push as much air. That resistance cuases power loss. But maybe I am wrong... I haven't played with either of the two...

[BGN]

Yes, but a SC does not have to spin as fast to create pressure. So by spinning it by hand, you could be creating pressure in the intake manifold which would cause resistance. Just speaking theoretically, I myself have no SC experience, so I could be completely wrong.

Gerry. turning the bolt by hand? And wouldn't it be easier to spin by turning the pulley?
I never just spun the pulley freewheel style, but If I change my pulley and am tightening the nut, if the belt is not real tight, the pulley spins and does not let me tighten the bolt.
I believe with the belt off, I can turn the pulley with a little resistance, but it will not rotate very far, probaly as you say a quarter turn.
There is defintely some drag to the rotation, but your hand should be able to
rotate the pulley, even if a little.

Another example Gerry, when I change my pulley, and have it off, I can rotate the shaft of the blower so the keyway is at 12 o clock, so it is easier to line the pulley back onto the shaft.
If I use my thumb and index finger, with ease I can rotate the shaft. It only rotates the blower the amount you turn it and it stops dead.

I believe you are describing NORMAL blower resistance, it does not freewheel, like your old TURBO.

Hope that helps you
And nice hearing from you and being able to respond, I hope all is well with you and your car!!

[GOTUBCH]

I know my AA rtrex supercharger I was unable to rotate by hand when it was shipped to me. Though at that point there was no oil in it either.

[Jimmyz2]

When I play with my 'blower' it also does not turn freely.

Jimmy, when I play with YOUR blower, SHE turns VERY FREELY

[BGN]

Lol

[Jimmyz2]

So that is why my blower's waste gate was plugged up.

[cgaffney004]

the blower will not spin freely because it is gear driven inside the housing, that is why it seems hard to spin, although you should at least be able to spin it with your hand with relative ease, it just will not spin freely

[stimpee]

Interesting.

The twin-screw compressor spins quite easily with just 2 fingers.

[cgaffney004]

I dont know twin screw superchargers, i spend most all my time working with centrifugal ones and turbos at my shop. But from what I have learned about twin screws, they seem quite good.

Stimpee(Steve) could write a book about the twinscrew.
Stimpee is the "father of the twinscrew" in BMW circles everywhere.
My hat goes off to him. His FI knowledge is IMMENSE.
And he is a "hell of a guy" to boot!!!!!

[Imported Cars]

Originally Posted by Marc1119

Stimpee(Steve) could write a book about the twinscrew.
Stimpee is the "father of the twinscrew" in BMW circles everywhere.
My hat goes off to him. His FI knowledge is IMMENSE.
And he is a "hell of a guy" to boot!!!!!

Yes he sure is without a doubt.

[cgaffney004]

well if he is the grand daddy of FI, then maybe he might know a thing or two about mounting a Non-VANOS head to an S50 block for forced induction crazyness, or should i just stick to the VANOS head?