Rear End Ratio

Reply Subscribe

Thread Tools

Search this Thread

Oct 15, 2002 | 08:39 PM

Bullyj

Thread Starter

Burning Brakes

Joined: Oct 2002

Posts: 971

Likes: 0

From: Rockwood TN

Rear End Ratio

At 55mph I turn 3000 rpm does anybody have an idea as to what my rear end ratio might be. (stock 350 180hp stock turbo 350)

Oct 15, 2002 | 08:44 PM

'79ProwlerOrange

Safety Car

Joined: Feb 2002

Posts: 3,556

Likes: 0

From: Seattle WA

Re: Rear End Ratio (Bullyj)

that sounds high for 3.55s, but thats possible. at 60-65 im doing 4000RPM and i have 4.11s(not factory)

Oct 15, 2002 | 08:48 PM

67HEAVEN

Le Mans Master

Joined: Dec 2000

Posts: 7,245

Likes: 4

Re: Rear End Ratio (Bullyj)

Don't forget tire diameter relative to original.

Oct 15, 2002 | 09:17 PM

GaryS

Melting Slicks

Joined: May 1999

Posts: 2,897

Likes: 0

From: Moon Township PA

Re: Rear End Ratio (Bullyj)

Take a look at the following web site:
http://www.idavette.net/tech/ratioc.htm

I used 26" for the tire diameter. Pretty accurate.
Gary

Oct 15, 2002 | 09:25 PM

Bullyj

Thread Starter

Burning Brakes

Joined: Oct 2002

Posts: 971

Likes: 0

From: Rockwood TN

Re: Rear End Ratio (GaryS)

Running 225 70 15 I think it's 26.5 diameter

Oct 15, 2002 | 09:42 PM

Schmucker

Melting Slicks

Joined: May 2002

Posts: 2,508

Likes: 0

From: Wisconsin

Re: Rear End Ratio (Bullyj)

I've got the same car and I have 3.55's factory. All the L48's had 3.55's for '77, L82's could come with 3.70 gears. So someone swapped your gears at some point, probably to 3.73s or 3.90s. I turn 3200rpm at 70mph. 245/60R15 tires.

[Modified by Schmucker, 7:43 PM 10/15/2002]

Oct 15, 2002 | 09:51 PM

Bullyj

Thread Starter

Burning Brakes

Joined: Oct 2002

Posts: 971

Likes: 0

From: Rockwood TN

Re: Rear End Ratio (Schmucker)

I turn 3750 at 70 mph

Oct 15, 2002 | 09:54 PM

Bullyj

Thread Starter

Burning Brakes

Joined: Oct 2002

Posts: 971

Likes: 0

From: Rockwood TN

Re: Rear End Ratio (Bullyj)

I used the calculator that gary had it said 4.11

Corvette Stories

The Best of Corvette for Corvette Enthusiasts

10 Ugly Corvettes That We Still Kinda Love

Joe Kucinski

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

Oct 15, 2002 | 10:26 PM

Paul L

Team Owner

Joined: Aug 1999

Posts: 30,995

Likes: 99

From: Ontario

Re: Rear End Ratio (Bullyj)

I would say that you have a 3.55:1. Here is mine at about 70mph (converted from metric).

Oct 15, 2002 | 10:58 PM

#10

ZL1powr

Pro

Joined: Jul 2002

Posts: 723

Likes: 0

From: North Port, FL

Re: Rear End Ratio (Bullyj)

For future reference you can use the following equation to compute Rear End ratio:

Rear Ratio = (D*RPM)/(336.14*Speed)

where D is tire diameter in inches and Speed is in MPH

This assumes the transmission gear is 1:1 i.e. 4th gear in a 4 spd. Otherwise the above formula gives you the product of the rearend ratio and the transmission gear ratio. I get 4.3 for D=26.5, RPM=3000 and Speed=55.