just wondering, what is the size of the crank pulley? as i understand there are seperate belts for the supercharger and for the engine accesories. whats the size of the pulley on the harmonic balancer/vibration dampner that turns the supercharger?

this would be important to anyone trying to use the m90 supercharger on another type of engine. this would prevent the user from having to switch supercharger pullies to come up with the stock amount of boost that the m90 produces on the 3800.

thanks folks!

[This message has been edited by merlot566jka (edited 05-06-2008).]

wait think i found it....7''

right?? anyone?

ill double check it if I can remember when I am in the shop tomorrow.

I believe it is 6.94" but 7" is close enough.

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11.806 @115.07
Best 60' 1.569 seconds
3800 S/C 4T65E

thank you

the stock size is 3.8" if you measure it across. So when you purchase one that is smaller, like a 3.4" it's not the circumference it's measured diagonal.

Joe

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crank pulley, not supercharger pulley

[This message has been edited by merlot566jka (edited 05-06-2008).]

It depends where you are measuring from. I'm pretty sure GM calls for the outer face diameter to be about 176mm max and the larger area where the balance holes are drilled to be about 182mm max.

176 = approx 6.9
182 = approx 7.2

So pretty much expect the very widest part of the crank pulley to be around 7.25" with rust, etc.

EDIT, I see you want it for belts. I read that at first but got a bit carried away and forgot as i went to type this message. Just use 7" as the others said above.

[This message has been edited by Jncomutt (edited 05-06-2008).]

7'' for the crank and 3.8 for the supercharger thats a 2.06:1 ratio. i could use this to find what size of pulley it would take to get the 3500 crank pulley to turn the supercharger at the right speed.

You're going to want to overdrive the supercharger anyways..

eventually.

id like to start conservitive first..then work my way up. besides i dont see this thing being able to do more than 14psi anyways. not without a ton of heat.

at like 10000 (sc speed) rpm it adds about 240*f to the intake charge..... yikes!