Rear End Recommendations??
Thread Starter
Burning Brakes
Joined: Dec 2007
Posts: 1,189
Likes: 0
From: Northwest Arkansas
Rear End Recommendations??
New rear-end is my next mod with Chuck Cow package... I see several options from 3.42, 3.73, 3.90 - even 4.10! How much is too much? Any recommendations on which setup?
I currently have stock 2.56 on my 2007 A6. I'm not heading to the track - just want that boost when I ask for it on street driving. Thanks for any constructive input you can offer.
I currently have stock 2.56 on my 2007 A6. I'm not heading to the track - just want that boost when I ask for it on street driving. Thanks for any constructive input you can offer.
Burning Brakes
Joined: Nov 2008
Posts: 908
Likes: 66
From: Lower RGV
St. Jude Donor '10-'11-'12
The A6 and M6 gear ratios are different. For A6 most people start out with a 2.56 and most upgrasde to a 3.15 or a 3.42 gear. I just talked to Quality Motorsports here in Dallas and they are about to install 3.73 gears on an LS3 with nitrous. I am looking to go 3.42 soon (hopefully this month). Quite a few here have 3.15 or 3.42 on their A6 trannies...perhaps they'll share their thoughts.
Pro
Joined: May 2007
Posts: 699
Likes: 0
From: Dallas TX
The A6 and M6 gear ratios are different. For A6 most people start out with a 2.56 and most upgrasde to a 3.15 or a 3.42 gear. I just talked to Quality Motorsports here in Dallas and they are about to install 3.73 gears on an LS3 with nitrous. I am looking to go 3.42 soon (hopefully this month). Quite a few here have 3.15 or 3.42 on their A6 trannies...perhaps they'll share their thoughts.
Melting Slicks
Joined: Jul 2007
Posts: 3,097
Likes: 5
From: Brentwood World's first A6 in the 9's (including N/A, blower, turbo and nitrous cars) 9.950@139.267 CA
New rear-end is my next mod with Chuck Cow package... I see several options from 3.42, 3.73, 3.90 - even 4.10! How much is too much? Any recommendations on which setup?
I currently have stock 2.56 on my 2007 A6. I'm not heading to the track - just want that boost when I ask for it on street driving. Thanks for any constructive input you can offer.
I currently have stock 2.56 on my 2007 A6. I'm not heading to the track - just want that boost when I ask for it on street driving. Thanks for any constructive input you can offer.
Burning Brakes
Joined: Nov 2008
Posts: 908
Likes: 66
From: Lower RGV
St. Jude Donor '10-'11-'12
Burning Brakes
Joined: Nov 2008
Posts: 908
Likes: 66
From: Lower RGV
St. Jude Donor '10-'11-'12
. I'm just needing to schedule my date/time with Quality Motorsports for 3.42 gears from RPM.I forgot on the earlier post....the A6 trans is doing fine. When I talked to RPM they said the primary concern with the A6 and high HP is making sure you get the trans tuned right and keeping trans temp down.
My attitude is, "if I blow the trans, I'll just have RPM rebuild me another." Life is too short, I'm going to enjoy it & my car while I can.
Race Director
Joined: Oct 1999
Posts: 13,298
Likes: 14
From: Somers NY
Have him make a few 1/4 mile runs see what his ET & MPH are with the stock gearing, then after he changes gears..
I have found on more than one occasion that
Horsepower = MPH
Chassis Set Up = ET .. in other words if he is NOT making more HP he is NOT going to pick up MPH.. yes gears will give him better ET..
And I have always said ET Wins Races Every Time, Not MPH!!
So yes the gears will get him a better ET (i.e Winning races) but his mph will stay within 1 or 2 from his original MPH..
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Michael S. Palmer
Former Vendor
Joined: Nov 2005
Posts: 11,792
Likes: 255
From: Ossining New York
St. Jude Donor '07-'08-'09-'10-'12-'13-'14
Regardless of what anyone else thinks or says...
New rear-end is my next mod with Chuck Cow package... I see several options from 3.42, 3.73, 3.90 - even 4.10! How much is too much? Any recommendations on which setup?
I currently have stock 2.56 on my 2007 A6. I'm not heading to the track - just want that boost when I ask for it on street driving. Thanks for any constructive input you can offer.
I currently have stock 2.56 on my 2007 A6. I'm not heading to the track - just want that boost when I ask for it on street driving. Thanks for any constructive input you can offer.
That's not to say that the bigger the gear the faster your car will be...
If the gear is properly matched to the motor's power curve with adequate traction....IT WILL BE FASTER.
It won't just "feel" faster....It WILL BE FASTER.
For most A6 vehicles...I'll take the thinking out of it for you.
3.42 A6 ATTACK PACKAGE!
You follow?
chuck CoW
Burning Brakes
Joined: Apr 2009
Posts: 1,155
Likes: 0
From: Kansas City MO
Sorry to hijack this thread. Chuck, I had an M6 in a 2001 TA making 508 hp and went from stock 3.42's to a Moser with 4.56's.
how does going from 2.56's to 3.42's in my 2007 A6 compare to an M6 gear change?
Hope this makes sense. I only know that the gearing is different in an M6 vs an A6.
how does going from 2.56's to 3.42's in my 2007 A6 compare to an M6 gear change?
Hope this makes sense. I only know that the gearing is different in an M6 vs an A6.
Drifting
Joined: Sep 2006
Posts: 1,657
Likes: 5
From: Orange CA
3.15 here
I lke my 3.15 because its gets out the hole quick.
With tire spin but not excessive. I think i am at 2500 rpm @ 70 mph.
I don't know what 3.42 will be at?
Either way you will get a kick in the a$$.
With tire spin but not excessive. I think i am at 2500 rpm @ 70 mph.
I don't know what 3.42 will be at?
Either way you will get a kick in the a$$.
Racer
Joined: Dec 2006
Posts: 256
Likes: 0
From: Newburgh Indiana
I love my 3.15's , but I'm running a little more horsepower than you . I am sure you would like either the 3.15 or 3.42 differential on a stock C6 . What Chuck says about " proper gear selection " is true . One should match their torque power curve to the gear . It is also nice to " tune " the new differential and decrease the shift time and clamping pressure . If you decide to tune your car , remove " torque management " so your car doesn't pull timing when shifting under full throttle . I will not make any claim that your car will be faster , but it will be even more fun to drive day to day . Enjoy !
Edit : I see that you already have a tune by Chuck , so I am sure that he has removed the torque management that causes many cars to " bog down " when shifting .
Edit : I see that you already have a tune by Chuck , so I am sure that he has removed the torque management that causes many cars to " bog down " when shifting .
Last edited by Larry R. Quinn; Jan 9, 2010 at 02:33 PM.
Former Vendor
Joined: Nov 2005
Posts: 11,792
Likes: 255
From: Ossining New York
St. Jude Donor '07-'08-'09-'10-'12-'13-'14
Not much difference.....except....
Sorry to hijack this thread. Chuck, I had an M6 in a 2001 TA making 508 hp and went from stock 3.42's to a Moser with 4.56's.
how does going from 2.56's to 3.42's in my 2007 A6 compare to an M6 gear change?
Hope this makes sense. I only know that the gearing is different in an M6 vs an A6.
how does going from 2.56's to 3.42's in my 2007 A6 compare to an M6 gear change?
Hope this makes sense. I only know that the gearing is different in an M6 vs an A6.
To perfectly match the power curve of a stock motor, it seems that the 3.42 is the best choice A) because there really isn't another ratio available without going to the extreme and 3.15s are great, but leave a lot on the table.... B) having 3.42s is almost "unnoticable" to the driver on the highway and around town....
You actually have to watch the tach to know there is a gear in the car.
I've taken many customers for rides in 3.42 cars and they never knew it had a gear....until the LAUNCH!
We've done all the hard work for you! All you have to do is write the check!
Chuck CoW
Instructor
Joined: Mar 2010
Posts: 160
Likes: 1
From: Chicago Illinois
Chuck, I have a 2010 GS A6 and am planning to upgrade to the edlerbrock 1591 SC package but wanted to do the rear end 1st and retune the trans. It looks like a 3.42 does the all all round trick for a DD and cruise mode. Really not into tracking it- YET !!!!
I know I need to retune the Trans but do I need an added cooler for it as well. That front end is going to get pretty crowded with all the mods. Do I need to send in the PCM to retune or is it downloadable????? Do I need to do it twice as well, once for the rear end, trans tune and then for the S/C?
I know I need to retune the Trans but do I need an added cooler for it as well. That front end is going to get pretty crowded with all the mods. Do I need to send in the PCM to retune or is it downloadable????? Do I need to do it twice as well, once for the rear end, trans tune and then for the S/C?
Former Vendor
Joined: Nov 2005
Posts: 11,792
Likes: 255
From: Ossining New York
St. Jude Donor '07-'08-'09-'10-'12-'13-'14
My advice would be.....
We have found 3.90s to be the best choice for C5 and C6 cars with A4 transmissions.
The difference between 3.73 and 3.90 is negligible and I believe the 3.90
is the better choice....
I have done MANY of them for Both C5's and C6s and I can mail order you a
perfect tune....
Especially when you buy the differential from US!
Stay TUNED!
Chuck CoW
Former Vendor
Joined: Nov 2005
Posts: 11,792
Likes: 255
From: Ossining New York
St. Jude Donor '07-'08-'09-'10-'12-'13-'14
Sorry to hijack this thread. Chuck, I had an M6 in a 2001 TA making 508 hp and went from stock 3.42's to a Moser with 4.56's.
how does going from 2.56's to 3.42's in my 2007 A6 compare to an M6 gear change?
Hope this makes sense. I only know that the gearing is different in an M6 vs an A6.
how does going from 2.56's to 3.42's in my 2007 A6 compare to an M6 gear change?
Hope this makes sense. I only know that the gearing is different in an M6 vs an A6.
Well, going from 3.42 to 4.56 is likely the same as going from 2.56 to 4.30 or 4.56
I would imagine....
The only thing to remember is that the A6 has an awesome FIRST GEAR and
two(2) really nice overdrives.
While the swaps DO compare as far as gains, please don't let that lead you to
believe that you're running around with the equivalent of 4.56s....
3.42s in an A6 car are AMAZING and the cars still get good mileage and
can cruise across the country with the best of them!
I wouldn't use any other ratio than 3.42 for an A6 car.
I LOVE REARS!
Chuck CoW
