ok, so i have an 87 IROC, and i was looking up the RPO codes and i dunno what this G92 code is for, is it a rare option for a ttop iroc?? just curious.

 

well im not an expert but i believe it is the performance rear axle with a good ratio such as 323 342 345 373 or something along those lines. ther is an rpo decoder on this site and numerous others in the web so a little detective work could help a lil more.good luck

 

tjhank you, i will look at the RPO decoder sometime tonight. is there any insight as to whether it was rare or not?i dont really car cuz the car is getting twin turboes and has no AC and is all ripped apart lol, just curious.

 

well i cant really help you ther as im a firebird guy rather than camaro but most of the ones i see are peg legs with like a 273 or some highway gear not even sure production numbers like that are available good luck, twin turbo?
wow gonna be crazy make sure everything is up to the task thats alot of oomph!

 

G92=Performance axle ratio. My car is a G92 car. Had 3.42 gears stock.

 

I'd like an expert to answer this.....in 87 what did G92 mean?


I had an 87 Players IROC (AU4) it had the GM3 3.45s but no G92

 

RPO codes don't change from year to year that I know of. G80 is a limited slip differential for my 91 Camaro. For a 06 cadillac cts a G80 is still a limited slip differential. The G92 is for performace axle ratio but does not specify axle ratio. I could be wrong though.

 

yes, it will be a built 305 Twin turbo. i am a firebird guy myself, but the iroc has a much more aggresive look to it. i like my firebird for DD and pickin up ladies, but the iroc is to defeat street bikes.

 

but RPOS codes do change. WS6 did several times in the 80's.

I know what your saying but why didn't my 3.45 car say G92?

 

RPO was performance axle ratio and over the years what it included varied in content.

 

As DJP87Z28 stated G92 was mainly the performance axle ratio option but it's content was added to some years.My '83 Z28 has it and the ratio is 3.23 with the LU5/700R4.On your SPID your axle code should be a "G" code.Also you can look on the passenger side axle tube - diff side about midways.The full code was stamped intoo the tube including build date(hopefully it's still readable).Another way is to pull the cover as it could have been chaged over the years.

And GM has a habit of reusing RPO codes but then some don't change.G80 has been posi-trac option code since the early '60s at least.

 

your not explaining why my 3.45 Players car did not have it.

GM3 is the RPO for the 3.45 and its a peroformance axle ratio

I had the KC4 oil cooler and J65 brakes too

 

For your '87 Iroc, if you have RPO G92 on your SPID, that means you have . . .
- LB9 305 TPI engine.
- G80 limited slip rear diff.
- J65 rear disk brakes.
- KC4 engine oil cooler.

As far as the rear performance diff goes, if you have the 5sp std tranny you'd then get the 3.45 ratio Borg-Warner 9 bolt. If you had the auto tranny then you got the 3.23 ratio.

Not sure how rare it is regarding the t-top. Probably not very. Even the convertibles could have the G92. Out of the total '87 Iroc production of 38,889 (plus another 744 Z28 & Iroc verts), 10,533 had the G92 option. That's a lot of G92's. Roughly 1 in 4 had it.

 

See above.


There were no 1LE's made in 1987. They didn't even exist until the following year, 1988 (and only 4 existed). And it wasn't until 1989 that the first 1LE's were imported into Canada to enter the Players racing series.
The reason why I'm mentioning this is that the 1LE was automatically triggered by the RPO G92 package. Your 1987 ride is not a 1LE, so this may not guarantee that it would also have the G92.
However, because your ride was an A4U Players Series car (AU4 is driver's side power lock), it would still include performance options. And one of those options may have been the GM3 3.45 rear ratio.

While I can't prove this 100% without more information (like seeing the original SPID, etc), it's a possible explanation.

 

G92 was a performance rear axle. It included a few other things, but the 87 mentioned above without G92 is probably because the car was ordered specific for racing. G92 included the oil cooler, 4 wheel disc brakes, posi and the best gear ratio available for the engine option. Based on your description, you didn't say anything about posi. Do you have that? If you don't have all the options, you don't have G92.

 

G92 is printed right on my RPO sheet. Yes, i have G92. if only the car was running today lol. oh well, next week.

 

yeah it had G80...otherwise would have sucked for raod racing! Forgot to mention that

Odd curioisity perhaps only in 87

 

Here's a partial list. You'll probably see G80, G92 and one of the ratio RPO numbers together.

G72 : AXLE REAR, 2.14 RATIO
G75 : AXLE REAR, 3.62 RATIO
G80 : AXLE POSITRACTION, LIMITED SLIP
G92 : AXLE REAR RATIO, PERFORMANCE
G9S : AXLE REAR RATIO, ECONOMY
GH0 : AXLE REAR, 3.54 RATIO
GH2 : AXLE REAR, 2.29 RATIO
GH3 : AXLE REAR, 2.77 RATIO
GH4 : AXLE REAR, 2.92 RATIO
GK9 : AXLE REAR, 4.63 RATIO
GL3 : AXLE REAR, 6.17 RATIO
GM1 : AXLE REAR, 2.59 RATIO
GM3 : AXLE REAR, 3.45 RATIO
GM8 : AXLE REAR, 2.56 RATIO
GS4 : AXLE REAR, 3.70 RATIO
GT4 : AXLE REAR, 3.73 RATIO
GT5 : AXLE REAR, 4.10 RATIO
GT7 : AXLE REAR, 3.33 RATIO
GT8 : AXLE REAR, 4.10 RATIO
GU1 : AXLE REAR, 2.41 RATIO
GU2 : AXLE REAR, 2.73 RATIO
GU4 : AXLE REAR, 3.08 RATIO
GU5 : AXLE REAR, 3.23 RATIO
GU6 : AXLE REAR, 3.42 RATIO
GV2 : AXLE REAR, 5.83 RATIO
GV4 : AXLE REAR, 3.36 RATIO
GV8 : AXLE REAR, 2.72 RATIO
GW4 : AXLE REAR, 3.31 RATIO
GW6 : AXLE REAR, 3.27 RATIO
GW9 : AXLE REAR, 2.93 RATIO