Which gears for automatic?
Burning Brakes
Joined: Apr 2003
Posts: 908
Likes: 4
From: TROY MI
[QUOTE=chaase]If you have 2.73 go to 3.42. It will be a world of difference. If you are going to put in a converter, go to 3.73.. I have 2800-3000 stall converter and 3.42 and I find myself having to drive faster to get better gas mileage. The 3.73 would eliminate that issue.
The stall on the converter eats up too much power below 1700rpm so I drive closer to 70mph to get the best mileage.
Chris[/QUOT
Your TC should be in lock up mode at those speeds and hence you should get the same mileage. My TC locks up at 38 MPH in OD. Now I lose mileage due to the gear(3.73) on the highway but not to the TC.
The stall on the converter eats up too much power below 1700rpm so I drive closer to 70mph to get the best mileage.
Chris[/QUOT
Your TC should be in lock up mode at those speeds and hence you should get the same mileage. My TC locks up at 38 MPH in OD. Now I lose mileage due to the gear(3.73) on the highway but not to the TC.
Last edited by yankeevetteconvert; Nov 29, 2006 at 03:24 PM.
Team Owner
Joined: May 2003
Posts: 23,480
Likes: 9
From: East Meadow NY
St. Jude Donor '12
Originally Posted by yankeevetteconvert
Your TC should be in lock up mode at those speeds and hence you should get the same milage. My TC locks up at 38 MPH in OD. Now I lose milage due to the gear(3.73) on the highway but not to the TC.
Maybe I am wrong and it is attributable to the altered power curve, but I noticed a difference
Chris
Burning Brakes
Joined: Apr 2003
Posts: 908
Likes: 4
From: TROY MI
Originally Posted by chaase
It does lock-up and you would think it wouldn't matter but it does...If I could get a flat highway with noone around it wouldn't be an issue, but since I have to make minor speed corrections for hills, traffic, it seems the engine bogs more at lower RPM and a require more pedal input to get the change in power/speed that I need.
Maybe I am wrong and it is attributable to the altered power curve, but I noticed a difference
Chris
Maybe I am wrong and it is attributable to the altered power curve, but I noticed a difference
Chris
With my 3.73 I can accelerate in OD from 1400 RPM with the TC locked. No stumbles/bogs just a smooth acceleration. Hoowever I still have the stock cam. How big a cam are you running?
Team Owner
Joined: May 2003
Posts: 23,480
Likes: 9
From: East Meadow NY
St. Jude Donor '12
Originally Posted by yankeevetteconvert
Wow!
With my 3.73 I can accelerate in OD from 1400 RPM with the TC locked. No stumbles/bogs just a smooth acceleration. Hoowever I still have the stock cam. How big a cam are you running?
With my 3.73 I can accelerate in OD from 1400 RPM with the TC locked. No stumbles/bogs just a smooth acceleration. Hoowever I still have the stock cam. How big a cam are you running?
Here is my dyno if it helps at all...
Chris
Last edited by chaase; Nov 29, 2006 at 03:56 PM.
Team Owner
Joined: Apr 2001
Posts: 26,794
Likes: 614
From: Elmhurst, IL (West Suburb of Chicago) & Home of MEGA Horsepower
St. Jude Donor '06
3.90s are the ULTIMATE GEAR for C5 A4 trannied cars when it comes to 1/4 mile performance. You will only spin about 100 to 200 rpm higher vs. 3.73s and with the overdrive tranny its a NO BRAINER. Just ask JOHNNY VETTES he just installed on in his 2000 A4 C5 and HE LOVES IT!!
Also, ROGER WHITE of yesteryear, had 3.90 gears in the fastest 1/4 mile cam only and heads and cam only C5 with A4 and stock shortblock, coupled with his YANK PROTHRUSTER 4000 Converter!!
4.10s would als work jsut fine, just ask RANDYVETTES!!!
Also, ROGER WHITE of yesteryear, had 3.90 gears in the fastest 1/4 mile cam only and heads and cam only C5 with A4 and stock shortblock, coupled with his YANK PROTHRUSTER 4000 Converter!!
4.10s would als work jsut fine, just ask RANDYVETTES!!!
Burning Brakes
Joined: Aug 2006
Posts: 789
Likes: 38
From: Shreveport LA
if you drive on the highway any I would go no higher than 3.73. 3.42's would be a great middle of the road gear. You will get plenty of fun from them and not have the hassle of high rpm highway driving.
Melting Slicks
Joined: Feb 2004
Posts: 2,791
Likes: 44
From: Loudon/Lake Mary Tennessee/Florida
Originally Posted by kingsey
How mutch would these changes cost installed?
I'd be interested in the cost to go from 2.73 to 3.42 also. I don't have the knowledge or equipment to do this so I'd like to know a typical cost installed.
Team Owner
Joined: Apr 2001
Posts: 26,794
Likes: 614
From: Elmhurst, IL (West Suburb of Chicago) & Home of MEGA Horsepower
St. Jude Donor '06
Originally Posted by Blue02ws6
if you drive on the highway any I would go no higher than 3.73. 3.42's would be a great middle of the road gear. You will get plenty of fun from them and not have the hassle of high rpm highway driving.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
Originally Posted by BLOWN ECS Z06
3.90s are the ULTIMATE GEAR for C5 A4 trannied cars when it comes to 1/4 mile performance.
Burning Brakes
Joined: Aug 2006
Posts: 789
Likes: 38
From: Shreveport LA
Originally Posted by BLOWN ECS Z06
You would be surprised that to see that the 3.90s only spin about 150 to 200 rpm higher than 3.73s and what the heck is the difference (when you really think about) between spinning at 2600 rpm or 2800 (with an overdrive tranny). It is only a neglible difference and may $100 a year in fuel tops!!
Team Owner
Joined: Apr 2001
Posts: 26,794
Likes: 614
From: Elmhurst, IL (West Suburb of Chicago) & Home of MEGA Horsepower
St. Jude Donor '06
Originally Posted by Blue02ws6
2822rpm at 80mph in overdrive is crap for the highway. I wouldn't do 3.90's. It only drops to 2700rpm for 3.73's but that is a little lower, I had 3.73's in an auto and I've had 3.42's in an auto. I would go with 3.42's for a DD that sees highway use and 3.73's or 3.90's if it hardly ever sees the highway.
This is all subjective and relative to any given individual, to me the motor is barely working at 2822 rpm and is BEGGING for more RPM!!!
SO i spend an extra $100 a year in fuel, big freakin deal!
Administrator
Joined: Mar 2001
Posts: 368,320
Likes: 24,777
From: In a parallel universe. Currently own 2014 Stingray Coupe.
C7 of the Year - Modified Finalist 2021
MO Events Coordinator
St. Jude Co-Organizer
St. Jude Donor '03 thru '25
NCM Sinkhole Donor
CI 5, 8 & 11 Veteran
I'd stick with the 3.42s. You will notice a nice improvement over the 3.15s.
Melting Slicks
Joined: Jan 2005
Posts: 2,409
Likes: 34
From: St. Louis Missouri
I would be careful when purchasing a used rear if you are not installing it yourself. If you get a bad one, you will be paying labor to remove it also and then you have to start all over with labor costs again. Lets just say I learned the hard way, and ended up buying a new one eventually.
Safety Car
Joined: Jan 2006
Posts: 3,940
Likes: 43
From: shavertown Pa.
rear
I had a3.15 in my 94, and it was a nice hwy. and local driveing rear, but it doesn't do much for you gas mileage, It would only do 18.
Where the 88 I had, was 2.59, a little slow but great mileage,
Where the 88 I had, was 2.59, a little slow but great mileage,
Team Owner
Joined: Apr 2001
Posts: 54,204
Likes: 180
From: S.W. Ohio. . . . . . NRA Life Member
Originally Posted by BLOWN ECS Z06
This is all subjective and relative to any given individual ... SO i spend an extra $100 a year in fuel, big freakin deal!
Burning Brakes
Joined: Aug 2006
Posts: 789
Likes: 38
From: Shreveport LA
Originally Posted by Mike Mercury
couldn't agree more. Our Corvettes are our fun car... not a mini-van. Have fun in your Vette, get the great gas mileage in your mini-van taking the kids to & from soccer practice.
You should put in 4.56's then those would be much more fun.
Some people actually have to drive on the highway even in their vette's, not to mention the people that use them as DD. I have had an auto with 2.73's, 3.42's, and 3.73's and a manual with 3.42's, 3.73's, 3.90's, 4.10's, and 4.30's. I think I can make an educated guess as what would be a good all around gear for most people.
Thread Starter
Burning Brakes
Joined: Nov 2006
Posts: 880
Likes: 0
From: Detroit Area Michigan
Originally Posted by brian vette
Went from 3.15 to 3.73 on the highway it revs about 2400 rpm at 70 mph for me that is just a little high so I drive 65 mph. Unless you drag race everyday don't go above 3.42
want a 3.73 rear ?
want a 3.73 rear ?Thanks for the reply. What would the rear cost, do you still have it or was that a joke, what about this hardened axle I keep hearing about, I'm new to Vettes, Thanks.