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Counterclockwise?
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Dual to single pulley
Now that my air con has been gone for years and I'm staring right at my double pulley would there be any performance gains in going to a single pulley?
I have one from an earlier car and it is a bit taller so hopefully I can change the shims to make the belt longer? Does this mod worth spending time on or should I do more important things like finishing my engine?
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Rod 1986 Carrera 2001 996TT A bunch of stuff with spark plugs |
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03-21-2016, 12:20 PM
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Finish the engine, and you would need a new belt , I doubt the shims will help if the pulley dia is different.
Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-) |
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03-21-2016, 07:34 PM
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Join Date: Feb 2004
Location: UK
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If you fit the smaller 116mm pulley you will effectively slow down the fan and the alternator by around 12%.
This will reduce parasitic losses due to windage but may reduce cooling a little in hot weather. If you use this crank pulley with a later fan you will need a belt with a length of about 695mm. |
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03-22-2016, 02:12 AM
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Join Date: Oct 2008
Location: Nash County, NC.
Posts: 8,471
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The largest pulley was used on the 77 to 79 with the like fan of the Carrera.
Install that pulley with a belt 9.5x725 you'll be good to go. Bruce |
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03-22-2016, 04:00 AM
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Counterclockwise?
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The Single pulley I have is slightly bigger so would it not increase my fan speed?
Are there any advantages to the lighter pulley?
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Rod 1986 Carrera 2001 996TT A bunch of stuff with spark plugs |
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03-22-2016, 05:09 AM
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Location: UK
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I always associate 'early' pulleys with the 116mm diameter of the early engines and these have a smaller effective diameter.
If you have a larger pulley then it will be faster 
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03-22-2016, 08:27 AM
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