Calderone

G92 differences with G44 both 3.07 but "performance" ?
What's the difference ?

GH0 Rear Axle, 3.54 Ratio
GM1 Rear Axle, 2.59 Ratio
GU2 Rear Axle, 2.73 Ratio
GW4 Rear Axle, 3.31 Ratio
G44 Rear Axle, 3.07 Ratio
G92 Rear Axle, Performance Ratio

c4cruiser

RPO G92 simply means that the car has an optional "performance" axle ratio. The "performance ratio" itself varied between the years, whether or not the car had a manual or automatic tranny and was a coupe or convertible.

For example, my old 92 convertible had the G92 performance ratio, but for that particular car (convertible with an auto trans) the "performance ratio" was only the GU2 2.73 gearset. The standard ratio for that car would have been the GM1 2.59.

Calderone

i see ! thanks
where are the performance equivalences by year ?

c4cruiser

You can look thru each model year of C4's here and ckick on "Specifications" or "Production and Performance"

The current issue of the Corvette Black Book will have the same information.

The earlier C4's didn't always have a separate defined axle ratio. For example the 87 had a 3.07 ratio as standard with the manual tranny; there was no optional ratio available. My '87's build sheet shows that G44 axle ratio.

Only the cars with automatics could get the optional G92 Performance Ratio G92 which was the same G44 3.07 ratio that the 4-speed cars had. The standard ratio for automatic cars in 87 was the 2.73 (RPO GU2)

2012 coupe

The rear carriers are as follows:

1. D36: GM1 Rear Axle, 2.59 Ratio
GU2 Rear Axle, 2.73 Ratio Both of these are the "Dana 2 Series"

2. D36: G92 Performance Ratio
G44 3.07 "Dana Series 3 carrier", different then #1 above

3. D44: "Dana Series 4"

There is a difference in #1 and #2 above in carriers and gears.