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Fast82930 Fast82930 is offline
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Join Date: Apr 2003
Location: Seattle
Posts: 195
Years ago I added the Andial 8:39 R&P to what was mostly my track car. Economical upgrade that I'm still happy with today. MPH changes from the 9:38 to the 8:39 are below:

1st gear @ 6.5k rpm - 52mph to 45mph
2nd gear @ 6.5k rpm - 90mph to 78mph
3rd gear @ 6.5k rpm - 132mph to 114mph
4th gear @ 6.5k rpm - 188mph to 163mph

A buddy years later built a big hp 930 and re-geared his to match 2nd-5th on a 915 box iirc. 1st gear was good to 72mph @ 7k rpm and riding with him as he geared down to 1st for turn 3A at Pacific Raceways was pretty cool. He shifted a lot more than I did each lap but had an "active" 4-speed. On the street his 1st gear was not much fun...

Paul Guard also suggested ratios for me before I went the 8:39 route. I did add his GT 50/80 LSD and sold the GT TB diff I had been running. That 80% lock really settled the rear down under heavy braking.

Factory
1st 2.250
2nd 1.304
3rd 0.893
4th 0.625

Paul Guard
1st 2.780
2nd 1.737
3rd 1.038
4th 0.767

Rob's monster
1st 1.736
2nd 1.303
3rd 1.000
4th 0.767
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Old 11-03-2017, 12:06 PM
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