Road Racing and Changing Rear Gear Ratio?

ntsi

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Need to get a new rear end in my car and I am looking for some input into switching the gear ratio from stock 3:07 to a 3:55 or 3:23. The car is mostly used for road racing and street driving.

What is the best gear ratio for road racing?
 

joe117

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A dedicated race car with a quick change rear would be geared so the top speed the car could reach on a given track would be near the top speed in top gear.
That would let the driver use all his transmission gears and this would give the driver the best chance that a given gear would be the best for any situation on that given track.

The Viper transmission has such a big jump between 5th and 6th that you probably won't be able to use 6th on the track.
So you have a 5 speed.

That would be what you would like in a dedicated race car.
You can't do that in your car. So it probably comes down to the track.

If I had to pick a rear ratio for you, I'd look at a 3.73 ratio. I'd figure out what your top speed in 5th would be with that 3.73 gear.

If that top speed is higher than what you would reach on the track you will be racing on, then I would go with that ratio.
 

SammyV

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ntsi, I have a 3.73 in my 2001 GTS. It will do 170 in 5th. I do most of my track driving @ Putnam Park. It is only 1.7 mi.but I like the way the car excellerates out of the corners! SammyV
 

joe117

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Gear the car so you get to use as many of the transmission gears that you can while on the track.
 

AG98RT10

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A lot of folks seem to favor stock (3.07) ratios for the track, but at VIR, which is a longish course with a 150 mph straightaway, I felt no penalty whatsoever with my 3.54 rear end ratio.
The difference it makes in everyday driving is worth the trade-off, whatever it may be, for tracking...
 

Chuck 98 RT/10

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3.07.

The higher ratios will produce more engine and gear heat. If there is a performance advantage to a higher gear I don't think it will offset the heat issue. JMO
 
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