Throwing Blower belt on a Screw Help

Discussion in 'PSI Superchargers Tech Questions' started by Scotttrod, Sep 13, 2013.

  1. Scotttrod

    Scotttrod Member

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    Throwing Blower belt on a Screw, Help

    We finally got to hit the track after working out some valve issues, and the blower belt is having trouble staying put. Threw it twice in the burnout or just after launch.

    14mm 1750mm 65mm wide, 54 tooth bottom pulley. Flange is center mount where the teeth are, flush with rear face of the pulley on the mounting flange. 24 top pulley. Threw different belts.

    Motor doesn't see more than 9200 rpm, and right at 7500 during burnout.

    Ideas?
    Thanks,
    ScottRod
     
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    Last edited: Sep 13, 2013
  2. Mark Leigh

    Mark Leigh Member

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    Have you tried a straight edge to see if all the pulleys are in the correct plane ?
     
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  3. Scotttrod

    Scotttrod Member

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    I'll look, I think it would be pretty hard for the blower/crank to be far off, idler could be a different story. I'll check them all, thanks.
     
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  4. Randy G.

    Randy G. Top Alcohol

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    The belt needs to be adjusted as tight as a guitar string. Any reason why you aren't running 8mm?
     
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  5. Mike Canter

    Mike Canter Top Dragster
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    If all the alignment is correct and it is adjusted correctly then you may have a fuel or ignition problem that us causing a backfire up into the blower. Check that all the port nozzles are clear, double check your plug wires are on the correct cylinders.
     
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  6. Scotttrod

    Scotttrod Member

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    I have been running 14mm with roots stuff for years, just went to screw. What is better about 8mm? I know a lot of guys run it, and 11mm too
     
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  7. bruce boland

    bruce boland Member

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    Throwing Belts

    An Alcohol Funnycar guy up here tried to run a 14ml belt with a D rotor. Had to have the belt piano string tight to keep it on. Then ran into breaking belts (maybe because it was to tight). Switched to 8ml end of problem.
     
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  8. Scotttrod

    Scotttrod Member

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    Thanks Bruce, do you run the 8mm tight to?

    Any particular kind of belt better than others? I use Gates Poly Chains on the 14mm
     
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  9. Randy G.

    Randy G. Top Alcohol

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    In the early days we ran 14mm on several varieties of root blowers. In 1996 when we switched to a screw we had to put a new belt on every run. Later, when they switched us to 92% overdrive we also switched to 8mm and suddenly we were getting 8 runs on a belt running the engine 9800-10200 RPM. Whatever belt you decide to run it has to be tight-tight.

    Mike Canter: You could have the motor pretty screwed up and it still shouldn't be tossing them on a burnout. I know two steps are hard on belts so coming off at or right after launch would be another story, but if they don't even make it through a 7500 rpm burnout then the alignment has to be way off or the belts are used/tired or they are loose.
     
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  10. bruce boland

    bruce boland Member

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    Belt

    Yes 8mill and very tight.
     
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