This is for the 87-92 TPI cars only, if you report a Camaro, or an LO3 or LG4 I will delete your post just be warned.

Post your Car: Formula, Trans AM, or GTA
your engine: LB9 or L98
Transmission: M5 or A4
Gear Ratio:

I am looking for a TPI Trans Am (NON-GTA) with a performance gear ratio to be specific, and I am looking for a TPI Formula or a GTA without the performance gear ratio.

The purpose is because Pontiac did not use the G92 option like the Chevy guys, I suspect it was model specific.

Thanks

John

 

1990 Trans Am GTA
L98
A4
Axle GU5 G80 (3.23 Limited Slip)

 

Here I am thinking about my 86 and totally forgetting I have an 89. I dont even know what gear is in it, tell you the truth. Must be a blank mind day.

Anyway

89 GTA
L98
A4 of course
3.27 I do believe, code says G80 if thats the right one.

I know you didnt ask but:
86 TA
LB9
A4
3.27 (option)

 

1991 Trans Am GTA
LB9/4L60
2.73
WS6 with no G92

1992 Trans Am GTA
Exact same as above

Did't G92 include the dual cats on the later cars and you could only get the dual cats and G92 on the later cars if you had the L98 or the LB9/T5 right?

I hate forgetting this stuff without practicing it...

 

1991 Firebird Formula
Engine: L98 w/G92
Transmission: A4
Gear Ratio: 3.23

 

hmm.

Ok, I was fortunate enough for a freind to send me the dealer order sheets for Pontiac Firebirds from 87-92.

As far as I can tell the RP6 is the Pontiacs equivelant to the Chevy G92

The later cars it appears that the GTA & Formula the "G92" came standard with the LB9/M5 combo and the L98 engine in 91 & 92. Apparently the A4 LB9 cars may have been only 2.73 in 91 I am just trying to figure this out...

According to the dealer order sheets the GTA came with the RP6 option standard on all engines in 92, but not in 91 or earlier.

In 1990 or prior its not really specified, oddly enough there is no reference to a performance option group at all. Not even a reference to a Performance axel ratio.

John
John

 

No RP6 here.
http://home.earthlink.net/~madmax0/8.../89vert47c.jpg

 

Odd because my 92 does not have have it either as I stated above even though you say it was standard. That doesn't sound right. I have my window sticker to proove it and that option was NOT deleted. I bet they meant it as standard on the GTA's standard engine, but then even that doesn't sound right because it was also standard on the LB9/T5.

IIRC too, it changed from G92 to R6P group which included the G92 RPO, around 89 or so...

BTW, I still have the original filled out order sheet for my old 91 Firehawk #003. It's in storage however so I can't take a look at. Can you scan and post the copies you have?

 

Dealer order sheet

 

I could not resize it to where you could read it on one post, so I split it in 2 the California option is so you can line it back up: enjoy

 

.

 

92GTA,
if you notice the R6P ( I mistyped earlier ) option is manditory on the GTA and with the 350 engine in 1992.

The 1991 is almost identical except it does not mandate the R6P in the GTA option, BUT it does mandate it with the 350 option. Also the 1991 does not give the option for T-tops with the Formula 350 with the PW7 wheels... I did not scan those pages.
-----------------
However I just noticed that in 91 & 92 the R6P was an option, never found it before BLIND I GUESS, But it was NA on the Formula and GTA. But its manditory with the LB9/MM5 & L98 on the Formula and GTA, apparently NA on 305/A4 cars, except possibly on the Trans AM.

The 1990 does not have it, nor can you seem to order it for anything but the Trans AM with the MM5,

John

 

The R6P group was not available on any 5.0L TPI/automatic Formula, Trans Am, or GTA in any model year. That is made clear in all the literature I have, either by exclusion or mention of a purchase credit.

John, the dealer order sheet I have for 1991 lists the R6P Group under "Additional Options" on the back side and the model restrictions/requirements are listed in fine print right next to it.

The 1991 and 1992 sheets do not mention R6P availability except with the LB9/MM5 and B2L/MXO combinations.... the LB9/MXO combo is not mentioned at all. By nature of exclusion, this tells me it was not offered. In fact, two of my other sources lists a $444 credit for LB9/MXO cars for both 1991 and 1992.

Apparently R6P was required on LB9 manual cars.... and not offered on the automatics.

As for the other info you asked about:

Model: 1988 GTA, GTA Notchback
Engine: 5.7L TPI, 5.7L TPI
Transmission: A4, A4
Axle: GW6, GW6 (3.27 Ratio)

 

Thanks Frankie, for everything... I knew you would have an answer if any one.

BUt I guess I should ask, what about 87-90, have you discovered anything that would suggest what would come with which ratio?

Here is the RPO list from my 2nd Formula that has the LB9/MM5/3.42 gear. No R6P, and no G92, but it has the performance axel... CAll me REALLY confused

John

 

HaHa.... you are too kind, John.

That RPO tag above lists a GM3 rear axle code.... which denotes a 3.45 axle. The 3.42 axle code is GU6.

All I know about 1987-90 is that certain combinations came standard with certain axle ratios. There is nothing mentioned on any sheets or in any of the Pontiac dealer sales booklets I have before 1991 that mentions the rear axle other than the G80 limited-slip code.

For instance, the 1987-89 GTA came standard with the GW6 3.27 axle with the 5.7L engine; apparently some years (mostly 1987 from what I have read) also had an optional (?) GU2 2.73 gear coupled with the 5.7L engine. I've seen mention of these in print, but never seen a car equipped like this in person. From 1990 on, the 5.7L GTAs used the GU5 3.23 axle.

The 1987-89 5.0L GTAs came standard with GU4 3.08 axle if the car was an automatic... the 5-speeds used the GM3 3.45 gearset. I have never seen any optional axles listed for a 5.0L TPI GTA of those years.

But all the 1990 models and the R6P group of 1991 and 1992 used the GU6 axle on the 5-speed cars of all models, and the GU5 axle on 5.7L cars of all models.

Another interesting thing to me is that the 5.0L/MM5 Formulas of 1991 and 1992 got the R6P group standard, but the Trans Am could be had with the 5-speed 5.0L TPI and without the R6P option. I guess that shows that by 1991, PMD considered the T/A more a luxury cruiser than a performance coupe?

BTW, there's nothing wrong with being confused about this stuff.... anybody that looks at it for more than 5 minutes ends up that way.

 

1988 Trans AM
305 TPI with A4
GU2/G80 2.73

1988 GTA Notchback (x3)
350 TPI with A4
GW6 3.27

 

1987 GTA
L98 A4 (originally)
GW6 G80 (originally, now GS4 G80)

 

Well, honk my hooter....

That shows us the 2.73 wasn't just used on the 350 cars, John.... Thanks, JT.

But why in the world would they put a 2.73 in any of these cars... and especially in a 5.0L/MXO car?

Hmmm.....

 

Here's the RPO for that car (the outlined was for a previous topic here):
<img src="http://www.gtanotchback.com/misc/88tarpo.jpg">

It also has the aluminum driveshaft and WS6 package.

 

I was beginning to think that almost all the 305 TPI/MXO (A4) cars (Firebirds) got the 2.73 gear... from 1987 - 92

John

 

89 formula
LB9 MM5
GM3
G80
NO DUAL CATS.
i do have the R6A RPO.
dunno how relivant this is to this subject.

 

R6A on an '89 Formula consists of T-tops and a UM6 cassette.... or upgraded UX1 cassette or U1A CD stereo. No R6P option in 1989.