ALT. Pulley on Supercharger

yeah, but at what cost....

i think the reason most people stop at the 10% is because the blower gets real close to its rpm limit with that pully, (something like 16,500). that smaller pully could be putting it way past its limit at the top end of the engine rpms. i'm not trying to disprove anything, just a warning if you're gonna try it.
 
One question I have is how did you get the alternator pulley to fit on the input shaft of the supercharger? It won’t just bolt on, The bore of the alternator pulley is larger than the shaft, not by much, but it is enough to cause problems. There is not a keyway in the alt. pulley, so the key has to be removed, or a keyway needs to be cut into the pulley (there isn’t enough meat to really add a keyway). The thickness of the mounting flange on the alt pulley isn’t thick enough and if the alt pulley is put onto the shaft the nut won’t hold the pulley be itself. There will be about ½” between the back side of the nut and the face of the alt pulley, making it super sloppy.

I really find it hard to believe that you (or your friend) made 15# of boost with a blower pulley that small. A lot of people have a hard time with a 10% pulley slipping much less one with one half the surface area, and not even a press fit. So how did you do it?

Jeff
 
I did a few calculations.

Boost would be a nice even 25 psi. (that is if the pulley and belt aren’t slipping)
Blower RPM at 5 grand (engine RPM) is 19,978 well over it’s limit.
The overall drive ratio is 3.9956809:1 compared to 2.71515:1 with an 89-93 pulley, so that’s what, a 32% overdrive. With a 10% the overall drive ratio is 3.034275:1


Jeff
 
I pin my boost at 15 with what appears to be a 10% pully..Was on there whne I got car...If I get slippag eIt will go down to about 13-14..Very close to the 15 mark..But then again..Its a factory gauge
 
Ya Damon I came up with

15.41 PSI 10%
14.07 PSI 5%
12.24 PSI stock 89-93
11.08 PSI stock 94-94

And a Whopping 24.95PSI with the Whopping 32% overdrive.

Granted this is taking into the account the old style blower.


But I really do want to know how he did it.

Jeff
 
ok

you see that the alt. pulley will fit, it's off a GM of some sort but he had some problems so he took it off. i just think he need more mod.s befor he goes that exatrem...but im sticking with the 10%....
 
GM pulleys only have 6 ribs (some 5), not 8 ribs like the accy. and upper blower drives on the SC (the lower one has 7).

So do you think you can find out which model GM car it came from?
It would be much appreciated.

Jeff
 
Well are you telling the truth or you FOS? I would like to know how this was done, if it was done at all. I emailed you privately, and got no response. So what’s the verdict? I know I can make it work, but if there is an easier way I would like to know.

Usually things that start out. My buddy had a friend that had a cousin that had picture of a boat that had a 45, 000 HP twin Turbine engine. And oh, one fed into the other so he could get more boost. But he lost the picture. Sound a little far fetched to me.

So are you hosing us or what?

Jeff
 
My input!

icon_bs.gif

And to quote my friend Forest Gump.
That's all I have to say about that
:rolleyes:
 
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