rear gears
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
Some of the C4 ratios/RPO codes that I found.
G92 - Performance axle ratio
GM1 - 2.59 Rear axle ratio
GU2 - 2.73 Rear axle ratio
G44 - 3.07 Rear axle ratio
GW4 - 3.31 Rear axle ratio
GT7 - 3.33 Rear axle ratio
GM3 - 3.45 Rear axle ratio
GHO - 3.54 Rear axle ratio
G92 - Performance axle ratio
GM1 - 2.59 Rear axle ratio
GU2 - 2.73 Rear axle ratio
G44 - 3.07 Rear axle ratio
GW4 - 3.31 Rear axle ratio
GT7 - 3.33 Rear axle ratio
GM3 - 3.45 Rear axle ratio
GHO - 3.54 Rear axle ratio
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
Thanks For the info guys .QCVette I see I have the crummy 2.59 gear ratio.I have to shift out of overdrive into drive going up hill because I have 17" rims and taller tires.
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
You are right QCVette.And my instant mileage Tells me I am getting 80 miles to the gallon,but that's down hill.You are correct I do get good mileage.That is a plus.
Last edited by steven mack; Sep 13, 2016 at 02:04 PM.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
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Thread Starter
Drifting
Joined: Oct 2006
Posts: 1,328
Likes: 14
From: Stafford Connecticut
I'm running 315-35-zr17.I don't have to shift out of overdrive .It's just more fun to be in my power band.There's a lot more in my motor I just have to get it tuned.I haven't tried tequilaboys tunes yet I am going to put the modified ECM in tomorrow.And thanks for the moates sight I had the memcal in wrong on the adapter.I didn't know the adapter would fit without taking the ECM case apart If I just removed the blue cover on the memcal.I can't believe Tequilaboy kept all my information on my chips he burned for me 5 years ago .He E:Mailed all the info to me last night.
Racer
Joined: Aug 2016
Posts: 354
Likes: 54
Factory gear ratios for '87...
Coupe was 2.59D36 base with auto, performance 3.07D36.
Coupe was 3.08D44 base or performance with std trans.
Convertible was 2.73D36 base with auto, performance was 3.07D36.
Convertible was 3.08D44 base or performance with std trans.
Coupe was 2.59D36 base with auto, performance 3.07D36.
Coupe was 3.08D44 base or performance with std trans.
Convertible was 2.73D36 base with auto, performance was 3.07D36.
Convertible was 3.08D44 base or performance with std trans.
