C6 A6 auto, Z51 - diff gear swap?
Thread Starter
Racer
Joined: Feb 2018
Posts: 303
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From: Arizona
C6 A6 auto, Z51 - diff gear swap?
(2007 C6 LS2 Z51 3LT A6) First and 2nd gears on these cars are SO LONG. Would it make sense to swap the rear-end gearing for something a little more peppy for real-world street driving? The A6, Z51 comes with the 2.73 gear ratio. Would it make a noticeable difference to swap it out with a Z06 3.42 diff? I believe the Z06 diffs are direct swaps even on "base" cars with an easily purchased larger rear cover. So, if I end up pulling out the rear end anyway, would it be worthwhile to look for a different unit? 3.42 vs 2.73 would make the 1st gear shorter and bring some life into the 2nd gear lower in the MPH range, which would make day-to-day driving a little more fun.
Good idea? bad idea?
Good idea? bad idea?
Last edited by mellojoe; Feb 10, 2020 at 04:54 PM. Reason: spelling
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(2007 C6 LS2 Z51 3LT A6) First and 2nd gears on these cars are SO LONG. Would it make sense to swap the rear-end gearing for something a little more peppy for real-world street driving? The A6, Z51 comes with the 2.73 gear ratio. Would it make a noticeable difference to swap it out with a Z06 3.42 diff? I believe the Z06 diffs are direct swaps even on "base" cars with an easily purchased larger rear cover. So, if I end up pulling out the rear end anyway, would it be worthwhile to look for a different unit? 3.42 vs 2.73 would make the 1st gear shorter and bring some life into the 2nd gear lower in the MPH range, which would make day-to-day driving a little more fun.
Good idea? bad idea?
Good idea? bad idea?
Safety Car
Joined: Apr 2007
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From: Houston TX
Pretty sure it comes with a 2.56 gear ratio. That is what is in my 07 A6 Z51. For day to day driving, I wouldn't want different gears. If it were a weekend toy I could see getting some lower gears if you like the torque it brings.
Race Director
Joined: Mar 2011
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2021 C6 of the Year Finalist - Modified
I would think that in a GS with the A6 transmission and the 2.73 axle ratio .... switching to a 3.42 axle ratio would make 1st gear pretty much useless.
Maybe I'm wrong ?
Maybe I'm wrong ?
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That's a common misconception but it's a great upgrade. It's only good for a tenth at the track (compared to a 2.56 diff) but makes the car a lot more fun to drive on the street. I only stopped driving my race car about 2 years ago but before that it had great street manners, even with the radical cam and 4000 stall converter.
Burning Brakes
Joined: Jan 2019
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From: Dallas, Tx
That's a common misconception but it's a great upgrade. It's only good for a tenth at the track (compared to a 2.56 diff) but makes the car a lot more fun to drive on the street. I only stopped driving my race car about 2 years ago but before that it had great street manners, even with the radical cam and 4000 stall converter.
Thread Starter
Racer
Joined: Feb 2018
Posts: 303
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From: Arizona
Thanks for the suggestions, friends. Again, think more for road racing and less drag strip. Think about coming out of slower corners. At around 30-35mph, coming out of a corner, that's an awkward spot. 2nd gear is down in the 2500 rpm range, which means shifting all the way down to 1st gear, up around 4800 rpm. Not bad,, but just a little awkward, like I said. 3.42 gears would mean those speeds in 2nd gear are up around 3000 to 3500rpm, which is right where you'd want to be and you don't have to touch 1st gear.