Want gears, need advise
Thread Starter
Instructor
Joined: Jun 2007
Posts: 133
Likes: 1
From: Atlanta GA
Want gears, need advise
Hi,
I've been talking with a friend who has a Mustang and chatting with people in these forums. It seems that changing gears in my C6 would be a very good first modification. I'm thinking of going with 4.10s. What I would like is some advise of where to go to get them done, which if any gears I should get, what to look out for, etc. I live in Atlanta but I'd consider any good shop within reasonable driving distance.. Oh yeah, how much should this cost me?
Thanks
I've been talking with a friend who has a Mustang and chatting with people in these forums. It seems that changing gears in my C6 would be a very good first modification. I'm thinking of going with 4.10s. What I would like is some advise of where to go to get them done, which if any gears I should get, what to look out for, etc. I live in Atlanta but I'd consider any good shop within reasonable driving distance.. Oh yeah, how much should this cost me?
Thanks
Racer
Joined: Jun 2007
Posts: 308
Likes: 0
Hey Red, please review my previous postings regarding the 4:10 ratio.
I'm 100% sold on the 4:10's. As far as Atlanta goes I can't help you there. I had a donor core build to spec by Corvettes of Westchester who is a Supporting Tuner on this forum but he is in the NY Metropolitan area. I think he'll also be at Carlise Pa in August.
I'm 100% sold on the 4:10's. As far as Atlanta goes I can't help you there. I had a donor core build to spec by Corvettes of Westchester who is a Supporting Tuner on this forum but he is in the NY Metropolitan area. I think he'll also be at Carlise Pa in August.
Thread Starter
Instructor
Joined: Jun 2007
Posts: 133
Likes: 1
From: Atlanta GA
Thanks for the tip. I did not know about the Year One Car show and Drag race this weekend... Can you give me some details? I would like to go. I was thinking of checking out Commerce this Friday, but I have not even looked at their website yet.....
Thread Starter
Instructor
Joined: Jun 2007
Posts: 133
Likes: 1
From: Atlanta GA
Hey Red, please review my previous postings regarding the 4:10 ratio.
I'm 100% sold on the 4:10's. As far as Atlanta goes I can't help you there. I had a donor core build to spec by Corvettes of Westchester who is a Supporting Tuner on this forum but he is in the NY Metropolitan area. I think he'll also be at Carlise Pa in August.
I'm 100% sold on the 4:10's. As far as Atlanta goes I can't help you there. I had a donor core build to spec by Corvettes of Westchester who is a Supporting Tuner on this forum but he is in the NY Metropolitan area. I think he'll also be at Carlise Pa in August.
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Thread Starter
Instructor
Joined: Jun 2007
Posts: 133
Likes: 1
From: Atlanta GA
I'll call them today!
Race Director
Joined: Oct 2004
Posts: 10,516
Likes: 2
From: Virginia Bch VA
Cruise-In VI Veteran
Cruise-In VII Veteran
St. Jude Donor '06
Instructor
Joined: Sep 2004
Posts: 239
Likes: 0
From: Jupiter FL
I also just ot a 2007 A6 Z51 and am wondering what gear ratio to go to. I had 3.90 rear from West Coast Corvettes in my 50th ann Z06 and it howled like a wherewolf (junk).
Would 4.10 be too low for the A6? 2.55 is way too high. I don't want to get something my wife can't drive on the highway.
Would 4.10 be too low for the A6? 2.55 is way too high. I don't want to get something my wife can't drive on the highway.
Instructor
Joined: Sep 2004
Posts: 239
Likes: 0
From: Jupiter FL
2.56 gear to 3.15 is 23% difference. 3.42 to 4.10 is 20% difference. I guess going from 2.56 to 3.15 is a bigger jump than 3.42 to 4.10.
Tell me if I am mistaken here but, it sounds like: an A6 doing 75mph at 1600 rpm in 6th with 2.56 rear, would be doing 1970 rpm with 3.15 gear.
That doesn't sound that bad. Then the car would be going 23% slower at the same rpm on the tach? 58 mph instead of 75?
If I don't get the speedo recalibrated, at 75 on the speedo I would really be only going 58. That sounds like a lot bigger difference than just 270 rpm.
Tell me if I am mistaken here but, it sounds like: an A6 doing 75mph at 1600 rpm in 6th with 2.56 rear, would be doing 1970 rpm with 3.15 gear.
That doesn't sound that bad. Then the car would be going 23% slower at the same rpm on the tach? 58 mph instead of 75?
If I don't get the speedo recalibrated, at 75 on the speedo I would really be only going 58. That sounds like a lot bigger difference than just 270 rpm.
Racer
Joined: Jul 2007
Posts: 292
Likes: 1
From: Chandler Arizona
2.56 gear to 3.15 is 23% difference. 3.42 to 4.10 is 20% difference. I guess going from 2.56 to 3.15 is a bigger jump than 3.42 to 4.10.
Tell me if I am mistaken here but, it sounds like: an A6 doing 75mph at 1600 rpm in 6th with 2.56 rear, would be doing 1970 rpm with 3.15 gear.
That doesn't sound that bad. Then the car would be going 23% slower at the same rpm on the tach? 58 mph instead of 75?
If I don't get the speedo recalibrated, at 75 on the speedo I would really be only going 58. That sounds like a lot bigger difference than just 270 rpm.
Tell me if I am mistaken here but, it sounds like: an A6 doing 75mph at 1600 rpm in 6th with 2.56 rear, would be doing 1970 rpm with 3.15 gear.
That doesn't sound that bad. Then the car would be going 23% slower at the same rpm on the tach? 58 mph instead of 75?
If I don't get the speedo recalibrated, at 75 on the speedo I would really be only going 58. That sounds like a lot bigger difference than just 270 rpm.
http://www.speedworldmotorplex.com/calc.htm
Pro
Joined: Nov 2006
Posts: 690
Likes: 0
From: IN (may-oct) FL (oct-may)
What mods, what tranny?
Hard to make a recommendation w/o your stating if you've got a manny tranny or an auto, 
and how much hp you're running. With 500+rwhp, I think my 427ci M6 is perfect with 3.90s, but if it was stock hp, or close, I would've went with 4.10s.
and how much hp you're running. With 500+rwhp, I think my 427ci M6 is perfect with 3.90s, but if it was stock hp, or close, I would've went with 4.10s.
VIR
Joined: Oct 2005
Posts: 1,443
Likes: 127
From: Palmyra Va
My 06/A6 has the 315 gearset.
The RPMs at speed are.
MPH----------------------------------RPM
45-----------------------------------1200
55-----------------------------------1450
65-----------------------------------1700
75-----------------------------------2000
85-----------------------------------2300
This has been a great mod for me. Hope this helps.
The RPMs at speed are.
MPH----------------------------------RPM
45-----------------------------------1200
55-----------------------------------1450
65-----------------------------------1700
75-----------------------------------2000
85-----------------------------------2300
This has been a great mod for me. Hope this helps.
Instructor
Joined: Sep 2004
Posts: 239
Likes: 0
From: Jupiter FL
Thanks kenw, that kind of proves out my idea.
How did you get your speedo recalibrated? is that process part of a tune?
I know from past experience that gear changing is one of the most dramatic and rewarding mods you can do.
Where do you recommend getting a good quality built and set-up rear?
How did you get your speedo recalibrated? is that process part of a tune?
I know from past experience that gear changing is one of the most dramatic and rewarding mods you can do.
Where do you recommend getting a good quality built and set-up rear?
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Thanks kenw, that kind of proves out my idea.
How did you get your speedo recalibrated? is that process part of a tune?
I know from past experience that gear changing is one of the most dramatic and rewarding mods you can do.
Where do you recommend getting a good quality built and set-up rear?
How did you get your speedo recalibrated? is that process part of a tune?
I know from past experience that gear changing is one of the most dramatic and rewarding mods you can do.
Where do you recommend getting a good quality built and set-up rear?
The 6 sp manual doesnt need a recalibrated speedo. The only advice I can give you is to try to find a tuner that does the build up of the rear in house or at least one that supplies the rear for you. If there is a problem with the diff the tuner will backstep if they didnt build or supply it. For example: going to DTE for a rear diff is a great option as is going to a tuner that gets one from DTE for you and installs it, but buying a DTE diff and taking it to the local GM dealership to have them install it isnt a good idea. From part to install, there needs to be accountability so if things dont work out, your car isnt sitting on a lift waiting for a working unit if the one you have doesnt work the first time around. This last path could see you paying for a retured unit that you supplied a mechanic that didnt know what he was doing and you pay storage for your car sitting on a lift.
Melting Slicks
Joined: Jun 2006
Posts: 2,690
Likes: 1
From: Northern Calif
Based on Spin's rec my tuner is put'n in the 3.15s in house. Cant wait! Although Spin rec waiting on a cam until after the gears, I couldnt resist and am getting a cam while there too. $$$ Sorry Spin, I didnt listen. I'll be the first to publicly say that you were right if it doesnt go well.
Instructor
Joined: Sep 2004
Posts: 239
Likes: 0
From: Jupiter FL
Sorry about the bio. I just filled it out. I have a 2007 Z51 A6 3LT coupe now. My 2003 Z06 got traded on it last week. The Z06 had 3.90 rear, drilled and slotted rotors with red hats and SS braided lines, Hawk ceramic pads, smooth intake, K&N, B&M short shifter and lots of interior mods with C6 aftermarket wheels.
I got the auto so my wife could drive it but, the 2.56 rear is WAY too tall for me.
I have read here that the A6 with a gear change has to have a tune to reset speedo. I also want the shift firmness improved. My 80 Malibu has a 350 turbo trans with a 3500 stall converter and a shift kit and I love the way it launches and shifts. I don't want my wife to have to live with that in a vette but need something a little more crisp.
I got the auto so my wife could drive it but, the 2.56 rear is WAY too tall for me.
I have read here that the A6 with a gear change has to have a tune to reset speedo. I also want the shift firmness improved. My 80 Malibu has a 350 turbo trans with a 3500 stall converter and a shift kit and I love the way it launches and shifts. I don't want my wife to have to live with that in a vette but need something a little more crisp.