Interesting. Given that I've seen 1,000HP conversion kits out there I assume these are fairly sturdy - more that I would have imagined from visual inspection. I'd say the same for the stock axle shafts.
GOOD GRIEF, isn't first gear short enough already?
I'd have thought so!
No point rowing around when you have massive torque like these cars have.
I use a 4.55 on the race car (25" diameter tires) and have even run 5.125, which gives you a top speed of about 90 MPH but you get there VERY quickly - good for hill climbs, but for the street you really want something a lot more relaxed.
The GXP has great pull low down plus decent top end. I would certainly change some of the transmission gear ratios, but not the diff.
1958 MGA Twincam (race car)
1962 MGA Deluxe Coupe
1969 MGC roadster,
1957 Jamaican bodied MGA
1965 Jensen CV8,
1971 Jensen Interceptor
1969 Lamborghini Islero S
1988 Pontiac Fiero GT
2009 Pontiac Solstice GXP Coupe
Bill in BC
I would think 3.91 would be a great compromise for the street between acceleration, top speed, and mileage. I ran 4.10's on my Mustang w/26" tires and ended up dropping back to 3.73 - 3.91 would have been great. (after I turbo'd I went back to 3.56)
I would say 4th gear is way too long for my tastes, I would love to loose most of the top speed but to eliminate that lazy ration of 4th gear.
__________________ Opel GT from Romania (EU) - You can always find me on the Kappa Performance Forum
Wester Race Tune - Solo catless dp, mach, quad tips - Dejon IC - KW V3 - Z0K swaybars - Custom Throttle Elbow - Custom Backbone Brace - ET 1/4 mile 13.30s
The Getrag differential is used in a couple other makes and models from GM. So your choices are 3.23, 3.42, 3.73(Redline/GXP), or 3.73(stock base).
Otherwise you can play with tire aspect ratio.
I think you made a typo, this was from another posting here and confirmed -
Second, the 2.0 final drive ratio is 3.73, vs. 3.91 on the 2.4.
I have both '07 rears on my cars and have not had time to inspect them for various mounting differences, but considering leaving the 3.91. Another poster on that thread indicated the BCM can be programmed for the different rear end ratio w/o issue, but it does need to be done if swapping things around.
'12 Kia Optima SX GDI turbo
'07 Custom Blue RL conversion, Auto (project - not running yet but working on it)
'06 Honda Odyessy EX-L minivan
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