14mm With Screw ?

Discussion in 'PSI Superchargers Tech Questions' started by TOL, Jan 19, 2015.

  1. TOL

    TOL Active Member

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    Can a 14mm belt be used with a screw at high overdrive? Or is there some downside to doing so? Just thinking if 8mm belt life is short, and the assortment of sizes for 11mm is limited, then why not a 14mm ?
     
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  2. sune

    sune Member

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    I don't think you can use 14mm belt with the PSI screws as they need the super high OD. But on the older whipples 14mm works really nice. never broke a single belt on my whipple, and i even run the narrow style belt. I use the HTD style 14mm.
     
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  3. KJC

    KJC Authorized Merchant

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    You can use 14mm pulleys at high overdrive.
    You will have to cut out the bottom of your fuel pump extension so that your bottom pulley will work.
    Kevin Cantrell
     
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  4. TOL

    TOL Active Member

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    And would belt life then be vastly improved versus what people are getting with the 8mm stuff up at around 225% over with an outlaw "C"?
     
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  5. overkill69

    overkill69 Member

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    14mm

    With 11mm you have to notch the fuel pump ext severely and the pulley looks like a pie plate. Even with that setup I think the dia. of the top pulley would not work well with 14mm.
    11mm is proven to live longer than the 8mm but most guys wont tolerate the weight penalty.
    There are also engineering issues with belt length and surface speed of the belt on the giant lower pulleys.
     
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  6. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    hp

    I have never backed to backed them on a dyno but the reason why everyone switched to 8 mm was they were supposed to be worth some hp vs 14 or 11.
     
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  7. hemi altered 378

    hemi altered 378 Blown Altered

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    I'm with Will on this one, don't have any data..... But I would bet anything that an 8 takes less hp to run than a 14. The 14 is 3 times more stiff it seems than the 8, there has to be a difference there.
     
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  8. Dale H.

    Dale H. Member

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    I have had good luck with 14mm at up to 105 over, but I know the 8mm are cheaper and depending on C/L distance between pulleys of the motor combo, the 14mm belt lengths vary with tooth design ie,HTD,GT etc.

    -Dale
     
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  9. Randy G.

    Randy G. Top Alcohol

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    Back when NHRA allowed TA/FC to run 125% we ran 14 MM belts because it was the only combo available at the time. It generated so much heat we had to put a new belt on every run because it literally melted the center out of the belt. Once an 8mm belt/pulley combo became available we switched and never looked back.
     
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  10. Scotttrod

    Scotttrod Member

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    I have heard the 8 is worth HP vs 11

    I have heard the 8 is worth HP vs 11. I ran 14 because I already had belts from my 14/71 setup, belts were flying everywhere..... At 86 over, 92 over, I was surprised when I did make a full run. Had to do something different.

    I am certainly not a guru like of bunch of the guys on here, but I went with the 11mm GT PS 84 1595 belt and all my troubles went away. And with high over drives too, 108, 120, 129 over. I run old fuel head junk for now, but made pulleys work with a +.100 deck.
    I know most guys run the 8mm, I the the "PS" in the belt designation is the key to the equation.
     
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  11. Blownalky

    Blownalky Top Sportsman

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    I was told third party that Pedregon thought there was 150 HP benefit from a 11 MM to 8 MM belt. RCD may know as they supplied him with the belts. I talked to Norm Drazy a few weeks back and he said the 11 was so much stiffer due to the requirements of the fuel application to keep from stretching and braking it but that it took more HP to bend it around screw blower pulley size.

    I just bought two Mitsuboshi 8MM belts in the 8mm GT 1672 84 size and will be mounting one of them up tonight. I needed the new 1672 size for my manifold configuration as my current belt size was limiting my pulley combinations. They say they are supposed to be better than the PS Gates belts, we'll see. Going to test it out next week down in Bradenton and I'll let you know if they stay on. I've had no issues with the 8MM GT 1600 84PS belts but I rarely go above 9k so that may what is letting me get away with it. Haven't chucked one on the two step yet either.
     
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  12. Scotttrod

    Scotttrod Member

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    How did it go?

    What did you think of the Mitsubishi belt?
     
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  13. Blownalky

    Blownalky Top Sportsman

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    Only made four runs and three were not the best, LOL but the belt was flawless. I tightened it up as much as possible per the recommendation and it held in there and did not stretch. The best thing I liked about it was that I didn't get the normal belt snow that I got with the Gates PS belts. Nice and clean. This was with a 35 top and 73 bottom pulley. I normally run with a 33 top so this didn't have as tight of a bend so we will have to see when I put the smaller one back on.
     
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