Choose your color scheme:
The Vette Barn  
 
Go Back   The Vette Barn > C5 Corvette > C5 Open Discussion

C5 Open Discussion General and technical C5 Corvette discussion - ownership, maintenance, repairs, modifications, tuning

User Tag List

Reply
 
Share Thread Tools Search this Thread
Old 12-22-2021, 7:03am   #1
Goodtogo32
Vette Barn nOOb
Points: 163, Level: 3
Activity: 2.6%
 
Goodtogo32's Avatar
 
Join Date: Nov 2021
Location: NJ
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Gameroom Barn Bucks: $500
Default rear axle ratios

How do I tell what the rear axle ratio is?
Goodtogo32 is offline   Reply With Quote
Old 12-22-2021, 9:09am   #2
73sbVert
Moderator
Barn Stall Owner #20
Barn Stall Owner #33

Barn Raising I,II
NCM Supporter '11,'13,'14,'20,'21
Bantayan Kids '13
Points: 27,151, Level: 100
Activity: 24.8%
 
73sbVert's Avatar
 
Join Date: Jan 2011
Location: Tucson, AZ
Posts: 21,481
Thanks: 14,299
Thanked 2,989 Times in 1,793 Posts
Gameroom Barn Bucks: $988270
Default

Quote:
Originally Posted by Goodtogo32 View Post
How do I tell what the rear axle ratio is?
You could look in your documentation if you have any! The Black Book will tell you what options were available for your year/model.

Or, lift the rear off the ground, put trans in neutral, mark a spot on both the driveshaft and a rear wheel (left I think works best?).
Spin the driveshaft by hand one complete revolution, and count how many times your wheel turns, and what fraction too.

There are only what? 3? ratios that were stock, you'll likely come real close to one of those.

Mine is 3.08:1, so the rear wheel turns just a tad past 3 complete revolutions. I believe there is also 3.55:1, and 3.73:1 as options.

HTH


Paul
73sbVert is offline   Reply With Quote
Old 12-22-2021, 1:19pm   #3
Y2Kvert4me
Administrator
Barn Stall Owner #7
Barn Raising I,II,IV

NCM Supporter '13,'14
Points: 32,246, Level: 100
Activity: 0%
 
Y2Kvert4me's Avatar
 
Join Date: Oct 2009
Location: Pewaukee,WI
Posts: 8,195
Thanks: 1,041
Thanked 4,884 Times in 2,181 Posts
Gameroom Barn Bucks: $30682687
Default

Quote:
Originally Posted by Goodtogo32 View Post
How do I tell what the rear axle ratio is?
Your post history indicates you have a 2003 Z06? If so, it came from the factory with a 3.42 rear end ratio. ALL 6spd C5s came with 3.42, there were no ratio options with the manual trans.

If the car is modified, it's possible someone upgraded the rear and changed the ratio. Available aftermarket ratios are 3.73, 3.90, and 4.10.
Note the rotation test described in the post above is impossible on a C5...Because there is no driveshaft. (the rearend is bolted directly to the transmission)

But what you can do is a simple drive test. Put the car in 6th gear, drive at exactly 60mph, and note the engine RPM.

1479 RPM = 3.42
1613 RPM = 3.73
1687 RPM = 3.90
1773 RPM = 4.10

(These calculated RPMs assume the Z06 M12 trans w/ 0.56 6th gear ratio, and stock 26.1" rear tire height. If your car has custom wheels/tires, specify the rear tire size and I'll recalculate the above RPM values)

Y2Kvert4me is offline   Reply With Quote
The Following 2 Users Say Thank You to Y2Kvert4me For This Useful Post:
Old 12-22-2021, 1:38pm   #4
73sbVert
Moderator
Barn Stall Owner #20
Barn Stall Owner #33

Barn Raising I,II
NCM Supporter '11,'13,'14,'20,'21
Bantayan Kids '13
Points: 27,151, Level: 100
Activity: 24.8%
 
73sbVert's Avatar
 
Join Date: Jan 2011
Location: Tucson, AZ
Posts: 21,481
Thanks: 14,299
Thanked 2,989 Times in 1,793 Posts
Gameroom Barn Bucks: $988270
Default

Quote:
Originally Posted by Y2Kvert4me View Post
Your post history indicates you have a 2003 Z06? If so, it came from the factory with a 3.42 rear end ratio. ALL 6spd C5s came with 3.42, there were no ratio options with the manual trans.

If the car is modified, it's possible someone upgraded the rear and changed the ratio. Available aftermarket ratios are 3.73, 3.90, and 4.10.
Note the rotation test described in the post above is impossible on a C5...Because there is no driveshaft. (the rearend is bolted directly to the transmission)

But what you can do is a simple drive test. Put the car in 6th gear, drive at exactly 60mph, and note the engine RPM.

1479 RPM = 3.42
1613 RPM = 3.73
1687 RPM = 3.90
1773 RPM = 4.10

(These calculated RPMs assume the Z06 M12 trans w/ 0.56 6th gear ratio, and stock 26.1" rear tire height. If your car has custom wheels/tires, specify the rear tire size and I'll recalculate the above RPM values)

Thanks Tom! Great info!

(sorry for steering the OP wrong on the d/s test, completely forgot about that)
73sbVert is offline   Reply With Quote
Old 01-08-2022, 9:50am   #5
Goodtogo32
Vette Barn nOOb
Points: 163, Level: 3
Activity: 2.6%
 
Goodtogo32's Avatar
 
Join Date: Nov 2021
Location: NJ
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Gameroom Barn Bucks: $500
Default

Thank You, good tip for using MPH vs RPM to get a idea. I'm second owner and previous owner made some changes with out documentation ;~(. Did a cam and valve springs also but no specs
Goodtogo32 is offline   Reply With Quote
Reply

The Vette Barn > C5 Corvette > C5 Open Discussion


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 11:58am.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2022 DragonByte Technologies Ltd.
Copyright 2009 - 2022 The Vette Barn


Support the Barn:
 
Download the Mobile App;
 
Follow us on Facebook:

Become a Stall Owner

 

Apple iOS App        Google Android App

 

Visit our Facebook page