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History / OriginalityGot a question about 1982-1992 Camaro or Firebird history? Have a question about original parts, options, RPO codes, when something was available, or how to document your car? Those questions, answers, and much more!
I previously owned a 1988 Formula 350, loved the car. it had roll your own windows and basically no power options like seats. It did have A/C. This car came with an aluminum driveshaft and spare without me even knowing about it being an option or special until 1990, when a good friend got one of the 28 350 ILE IROCs that also had them.
I have always wondered if this was a mistake, an option that was simply checked, and if so, what option was it. I seem to remember hearing those parts with A/C could be had with a police option.
If anyone has good information about this, I would love to hear it. Thank you.
1988 Formula 350 Firebird
Black L98 Auto
purchased in August of 1988
Colonial Pontiac, Lawrenceville, GA
I previously owned a 1988 Formula 350, loved the car. it had roll your own windows and basically no power options like seats. It did have A/C. This car came with an aluminum driveshaft and spare without me even knowing about it being an option or special until 1990, when a good friend got one of the 28 350 ILE IROCs that also had them.
I have always wondered if this was a mistake, an option that was simply checked, and if so, what option was it. I seem to remember hearing those parts with A/C could be had with a police option.
If anyone has good information about this, I would love to hear it. Thank you.
1988 Formula 350 Firebird
Black L98 Auto
purchased in August of 1988
Colonial Pontiac, Lawrenceville, GA
I would like to know more about this as well....
I have an 88 Formula 350 optioned the same as your old car with both the aluminum driveshaft and spare.
After hearing about your 88 Formula, I am wondering if it was something standard on all 1988 Formula's ??
Here is my SPID tag - JG1 is for the aluminum driveshaft and N64 is the stowaway spare (which I believe is the aluminum spare).
It's interesting that in Robert Casey's Firebird codes book N64 is only listed for 1988 GTA's and not for the Formula's.....
Hello BizJetTech... good to hear I am not the only curious one. As a mechanic I have seen many Firebirds from that era without the aluminum driveshaft, pretty sure some were T/As, Formulas and GTAs. Never checked many of the spares. When my friend got her 1LE, another friend was telling me of the special aluminum driveshaft. I was like, "it's not special, my Formula has one". He didn't believe me, so he ducked under and came away with surprised look. Afterwards we checked my spare, also aluminum to his surprise. Might have simply been an option, but most seemingly, did not have it. I know my car was a bit faster than average, less weight all around than the T/As with body panels and power options. Unfortunately a guy in a full size Blazer didn't stop at a red traffic light, rear-ended me and destroyed mine (sad day). I do still have the paperwork, I will look for it and post a pic of the build sheet that I have. Thanks.
Hello BizJetTech... good to hear I am not the only curious one. As a mechanic I have seen many Firebirds from that era without the aluminum driveshaft, pretty sure some were T/As, Formulas and GTAs. Never checked many of the spares. When my friend got her 1LE, another friend was telling me of the special aluminum driveshaft. I was like, "it's not special, my Formula has one". He didn't believe me, so he ducked under and came away with surprised look. Afterwards we checked my spare, also aluminum to his surprise. Might have simply been an option, but most seemingly, did not have it. I know my car was a bit faster than average, less weight all around than the T/As with body panels and power options. Unfortunately a guy in a full size Blazer didn't stop at a red traffic light, rear-ended me and destroyed mine (sad day). I do still have the paperwork, I will look for it and post a pic of the build sheet that I have. Thanks.
Hey there Keith, I'd enjoy seeing the build sheet you have, I hope to find one for my car.....would be cool if we could figure this one out - Thanks
The spare was triggered by G80. With a limited slip, the spare needs to inflate to the same diameter as a regular wheel/tire combo to prevent wearing the differential. That it or the driveshaft was aluminum had more to efficiency, emissions, and CAFE. An aluminum driveshaft and spare was an easy place to drop some dead weight. 88 & 89 were prime years for the JG1 shaft, you'll find a ton of them in basic L98 cars. It wasn't really something they did special for performance, because a lot of the cars it went on were the 2.77 geared non-G92 types. Pretty sure I've even seen the JG1 shaft on 88 and 89 Irocs with 15" wheels.
When you get into the later cars, you'll see the JG1 shaft less often. Usually on GTAs, and of course 1LE cars. When you get into the LT1 cars, the aluminum shaft was a service part, that was installed when people complained about driveline vibrations. Again, not really a performance part, more of a solution to a specific issue.
The spare was triggered by G80. With a limited slip, the spare needs to inflate to the same diameter as a regular wheel/tire combo to prevent wearing the differential. That it or the driveshaft was aluminum had more to efficiency, emissions, and CAFE. An aluminum driveshaft and spare was an easy place to drop some dead weight. 88 & 89 were prime years for the JG1 shaft, you'll find a ton of them in basic L98 cars. It wasn't really something they did special for performance, because a lot of the cars it went on were the 2.77 geared non-G92 types. Pretty sure I've even seen the JG1 shaft on 88 and 89 Irocs with 15" wheels.
When you get into the later cars, you'll see the JG1 shaft less often. Usually on GTAs, and of course 1LE cars. When you get into the LT1 cars, the aluminum shaft was a service part, that was installed when people complained about driveline vibrations. Again, not really a performance part, more of a solution to a specific issue.
Drew, thanks for the info, I knew I could count on you to jump in this one Mr. Wizard....
Interestingly enough, my 2 previous 89 Formula 350's did not have RPO JG1, this is the first car I've had with it,
my old 87 GTA did not have it either.
I'm thinking 88 was the first year. Can't remember seeing them before that.
For whatever reason, enough changed in 90, that GM changed the camshaft in TPI cars, along with the speed density changeover, T-top + 350 cars generally went away, and the aluminum driveshaft got less common. Probably due in part to changes in efficiency and strategy. Of course this is predominately conjecture based on general impressions and what the facts suggest. Most logical explanation that fits the facts. It's always open to further documentation and different interpretation, but that is what the facts suggest to me - I could be wrong.
Thanks Drew, that helps to shed some light on the subject. I can attest to the fact that as much as we would like for GM execs to be car guys, they are business guys, and are often more driven by other factors, such as government CAFE you mentioned, profits than they are making performance options we would all love. It's often hard to determine the things that affect their strategy, thankfully a few of them saw the light.
My 1987 5.7 Iroc, has a steel shaft, my 89 GTA 5.7 has aluminum. I recently had an 89 5.0 Iroc with a steel shaft.
The weight thing makes sense as the 5.7 added a tiny bit of weight to the cars iirc? Wasn't weight the purpose of the lexan tops on the 5.7 GTA in 89? Thought I read that on this site a few years ago.
my 87 has the aluminum spare & the GTA is supposed to have it, but it has a steel wheel. Could have been swapped by the dealer that had the car on their lot back in 1992. But looks completely correct & unmolested. SPID tag says it should be aluminum however.....
There are two aluminum spares. The cast aluminum version with spokes, that was used until 88, and a stamped aluminum version that looks like a regular steel spare from 89-92. The spoked spare won't fit over the PBR rear discs, the stamped aluminum wheel is a 15" wheel that clears the PBRs.
There are two aluminum spares. The cast aluminum version with spokes, that was used until 88, and a stamped aluminum version that looks like a regular steel spare from 89-92. The spoked spare won't fit over the PBR rear discs, the stamped aluminum wheel is a 15" wheel that clears the PBRs.
The 15" aluminum spare uses a different size inflator can! If you compare the cans from a 10-spoke car and a stamped car, the stamped can is an inch or two taller, and the label even says it works with the 15" spares. LOL
The 15" aluminum spare uses a different size inflator can! If you compare the cans from a 10-spoke car and a stamped car, the stamped can is an inch or two taller, and the label even says it works with the 15" spares. LOL
Cool stuff - ever think about writing a book ??
You could write the third gen F body bible.....
Hi there,
I go along with Drew that these parts are meant for weight-saving, not performance. I have a '91 TA, LB9 auto, with T-tops. It has aluminum driveshaft, spare and drums. And 2.77 G80 gears, so not a performance package!
There are two aluminum spares. The cast aluminum version with spokes, that was used until 88, and a stamped aluminum version that looks like a regular steel spare from 89-92. The spoked spare won't fit over the PBR rear discs, the stamped aluminum wheel is a 15" wheel that clears the PBRs.
Wow, I had no idea. I just assumed they all used the first design. I didn't realize the 89 brakes where bigger than the 87 style either. Pretty sure my spare looks just like the second picture. Honestly, I have been watching for a mint unused older style spare until reading your post. I am the third owner of the 89 & the original & second owner did nothing with the spare, so I assumed it was the dealer who took it on trade or GM ran out of aluminum spares.
Hi there,
I go along with Drew that these parts are meant for weight-saving, not performance. I have a '91 TA, LB9 auto, with T-tops. It has aluminum driveshaft, spare and drums. And 2.77 G80 gears, so not a performance package!
Not sure I agree with you about the weight savings purpose - my Formula, which is one of the lightest 3rd gens to begin with is a very lightly optioned car
(no power windows or locks, etc). so it was light to begin with, so why would it need to have a light weight spare and drive shaft? Additionally, I've seen heavily optioned
GTA's (which were some of the heaviest 3rd gen cars) with the standard steel spare and driveshaft - there is no rhyme or reason to it in some cases
Wow, I had no idea. I just assumed they all used the first design. I didn't realize the 89 brakes where bigger than the 87 style either. Pretty sure my spare looks just like the second picture. Honestly, I have been watching for a mint unused older style spare until reading your post. I am the third owner of the 89 & the original & second owner did nothing with the spare, so I assumed it was the dealer who took it on trade or GM ran out of aluminum spares.
Will do! My cars are stored about 6 miles from my home, so might be a week or so before I stop there. And then I need to remember to check (& bring a magnet)
There are two aluminum spares. The cast aluminum version with spokes, that was used until 88, and a stamped aluminum version that looks like a regular steel spare from 89-92. The spoked spare won't fit over the PBR rear discs, the stamped aluminum wheel is a 15" wheel that clears the PBRs.
People are still selling the 10 spoker, representing them as a "1LE spare".
BTW, there is also a different RPO code on the SPID between the steel spare and the stamped Al one that clears the PBRs. There's a thread on it somewhere, I can't remember the two codes.
BTW, there is also a different RPO code on the SPID between the steel spare and the stamped Al one that clears the PBRs. There's a thread on it somewhere, I can't remember the two codes.
BTW, there is also a different RPO code on the SPID between the steel spare and the stamped Al one that clears the PBRs. There's a thread on it somewhere, I can't remember the two codes.
Not sure I agree with you about the weight savings purpose - my Formula, which is one of the lightest 3rd gens to begin with is a very lightly optioned car
(no power windows or locks, etc). so it was light to begin with, so why would it need to have a light weight spare and drive shaft? Additionally, I've seen heavily optioned
GTA's (which were some of the heaviest 3rd gen cars) with the standard steel spare and driveshaft - there is no rhyme or reason to it in some cases
I believe there were some rhyme and reason to GM's choices, in fact. I read somewhere it had to do with EPA weight classes. For instance, check out this link: https://books.google.com/books?id=qU...bution&f=false
As pages 197 and 198 explain, the dynamometer equipment used for EPA testing could only be set to a finite number of discrete test weights, so each car's weight was rounded off to the nearest test weight. The chart on page 198 shows that at least in 1977, the weight classes were pretty coarsely set (250 pounds apart). Therefore, if a car was close to the boundary between two weight classes, the manufacturer had a strong incentive to add some aluminum to get down to the lower weight class. So if adding aluminum and saving for instance 35 pounds crossed the boundary into the lower weight class, the manufacturer could get credit for 250 pounds of saving. On the other hand, if one had an even heavier car, and 35 pounds wouldn't do the trick, the manufacturer would get no credit, so they wouldn't use the more expensive aluminum parts. That is why one can find lighter cars with the aluminum parts and heavier cars without the aluminum parts.
The government was aware of this too, as this document notes that the actual weights were not uniformly distributed across each weight class. Because of the "gaming" going on, there were more cars in the upper end of each weight class than in the lower end of each weight class (again, see page 198).
I believe there were some rhyme and reason to GM's choices, in fact. I read somewhere it had to do with EPA weight classes. For instance, check out this link: https://books.google.com/books?id=qU...bution&f=false
As pages 197 and 198 explain, the dynamometer equipment used for EPA testing could only be set to a finite number of discrete test weights, so each car's weight was rounded off to the nearest test weight. The chart on page 198 shows that at least in 1977, the weight classes were pretty coarsely set (250 pounds apart). Therefore, if a car was close to the boundary between two weight classes, the manufacturer had a strong incentive to add some aluminum to get down to the lower weight class. So if adding aluminum and saving for instance 35 pounds crossed the boundary into the lower weight class, the manufacturer could get credit for 250 pounds of saving. On the other hand, if one had an even heavier car, and 35 pounds wouldn't do the trick, the manufacturer would get no credit, so they wouldn't use the more expensive aluminum parts. That is why one can find lighter cars with the aluminum parts and heavier cars without the aluminum parts.
The government was aware of this too, as this document notes that the actual weights were not uniformly distributed across each weight class. Because of the "gaming" going on, there were more cars in the upper end of each weight class than in the lower end of each weight class (again, see page 198).
Very interesting - thanks for sharing,
that makes sense in the case of my Formula example
Other than just speculation, anyone have info on why all B4C 1LEs have steel DS and not JG1? I assume durability, but does anyone have any facts?
Just speculation, but why would a B4C require JG1? A B4C isn't a 1LE in the traditional sense. A B4C as far as GM cared was just a regular Z28. Just like most 91-92 Z28s don't have JG1, the B4C wouldn't suddenly need it solely because the car had upgraded front brakes.
Now if B4C 1LE cars were built in 88-89 I'd bet they would have JG1.
Not sure I agree with you about the weight savings purpose - my Formula, which is one of the lightest 3rd gens to begin with is a very lightly optioned car
(no power windows or locks, etc). so it was light to begin with, so why would it need to have a light weight spare and drive shaft? Additionally, I've seen heavily optioned
GTA's (which were some of the heaviest 3rd gen cars) with the standard steel spare and driveshaft - there is no rhyme or reason to it in some cases
I would assume that GM probably had an algorithm that compiled build data and spit out a build sheet with certain items determined by the computer. JG1 wasn't a stand alone option the customer selected or ignored. It wasn't part of a specific package. Like aluminum drums, aluminum impact bars, spring rates, etc the aluminum shaft was magically selected based on other factors. It only makes sense that a computer decided at some point that this car or that car should have an aluminum shaft to meet a predetermined requirement.
It could be something as simple as a requirement that for every X number of cars, Y quantity could be built before encroaching on a CAFE penalty. So to avoid that penalty, perhaps JG1 was selected to help meet the predetermined numbers. Say GM figured that the JG1 shaft was good for a minute improvement, that when applied to 500 cars, it saved enough economy (efficiency, emissions, whatever), that it allowed them to build 50 cars that normally would push CAFE requirements over the limit.
So then maybe in 1990 when GM switched to Speed Density, and a smaller HO camshaft than they needed in 89, maybe it skewed the numbers far enough to the positive that the computer didn't need to apply the aluminum shaft. Maybe GM found that Z percentage of saved economy somewhere else that was cheaper than using aluminum driveshafts.
At least that's the way I look at how GM could have made some of these decisions. To our eyes, something seems insignificant, but taken over hundreds or thousands of units, that .00005% + or - to the bottom line made a huge difference in the numbers to GM.
I can't remember the last '91-'92 Trans Am convertible I've seen, that didn't have a JG1.
How many 5 speeds did you look at? My 1992 T/A Convertible 5-speed doesn't have JG1. According to Compnine none of the 5 Speed T/A Convertibles show JG1 for 1992.
How many 5 speeds did you look at? My 1992 T/A Convertible 5-speed doesn't have JG1. According to Compnine none of the 5 Speed T/A Convertibles show JG1 for 1992.
Come to think of it, the ones I remember were were autos. Maybe the 60-ish pound difference between a T5 and 700R4 was enough to trigger JG1?
In 1988 There was
3563 JG1 Formulas
3158 JG1 Trans Ams
7779 JG1 GTA's which is exactly the same number as L98 cars
JG1 for 1989 is a different bag
0 Formulas
639 Trans Ams, which is also exactly the same number as rear disc brake J65
7553 GTA's which is exactly the same number as the number of L98 cars...
1990
Again ZERO Formulas
682 Trans Ams
1312 GTA's
From the information I see, 1988 was the only year for the Formula to get the JG1 according to GM. It had to be a weight savings program, even the 91/92 Trans Am Convertibles got it as an option.
John
In 1988 There was
3563 JG1 Formulas
3158 JG1 Trans Ams
7779 JG1 GTA's which is exactly the same number as L98 cars
JG1 for 1989 is a different bag
0 Formulas
639 Trans Ams, which is also exactly the same number as rear disc brake J65
7553 GTA's which is exactly the same number as the number of L98 cars...
1990
Again ZERO Formulas
682 Trans Ams
1312 GTA's
From the information I see, 1988 was the only year for the Formula to get the JG1 according to GM. It had to be a weight savings program, even the 91/92 Trans Am Convertibles got it as an option.
John
Those 3563, '88 Formulas are curious. JG1 and possibly the 10 spoke N64 were used as "trick" by GM to have get cars into a different EPA weight class. You'd think those Formulas would have been light enough? Or maybe not?
The N64 numbers for 1988 are identical to the Aluminum driveshaft... Definitely a weight savings thing.
1988 N64
3563 Formulas
3158 Trans Ams
7779 GTAs
89 is a bit more of a mixed bag...
1989 N64 & J65
6002 Formula (4875 L98, 1126 LB9/MM5/GM3)
639 T/A (613 L98, 26 LB9/MM5/GM3)
9131 GTA
1990 N64
1815 Formula
682 Trans Am
1435 GTA
1990 J65
Formula 1191 (353 LB9/MM5 or 838 L98)
T/A 67 (4 LB9/MM5 or 63 L98)
GTA 1225 (123 LB9/MM5 or 1002 L98)
The N64 numbers for 1988 are identical to the Aluminum driveshaft... Definitely a weight savings thing.
1988 N64
3563 Formulas
3158 Trans Ams
7779 GTAs
89 is a bit more of a mixed bag...
1989 N64 & J65
6002 Formula
639 T/A
9131 GTA
Is a Formula inherently heavier than an IROC? Those flip up lights have to add a few pounds.
Years ago, I weighed a few of my cars on a truckstop scale. Ironically (?), I can only find the slips for my 91 Formula and 91 Firebird. I'm sure I weighed the Iroc, and I'm pretty sure I remember the general weight, but without the slip I'd just be guessing. I can tell you a fully loaded 3.1L Firebird with GFX, lexan T-tops, and 4th gen leather seats, was only 100lbs less than the Formula 350 hardtop.
Illustrates that perceived weight doesn't always pan out the way people expect. I'd post the weight of my Formula for comparison, but someone would probably make up a random lighter number - just because they can. Besides, who can say the margin of error between two different scales.
Doubt there is much difference in weight between the front end of a Formula and an Iroc. Pop-up lights vs a separate high/low sealed beam, fog-lights vs no fog-lights, gfx vs no gfx, header panel vs no header panel. Balances out a bit in the wash.
The Formula was lighter than all of the other Performance F-bodies. The Lack of GFX was probably the biggest determiner of this, but there was other things, like my 87 did not have the rubber pieces on the bottom of the doors by the upholstery. Although you could option them up with creature comforts, Formulas were intended to be the stripped down Performance pony car of the era, intended to go head to head with the Mustang LX 5.0. I remember looking at an 88 Formula 350 with no options, no AC, no power locks/doors/cruise... this car was bare bones, the only option it had was a power antenna, which threw me. Looking back I wish I would have picked it up, but it was kind of beat.
The Formula was lighter than all of the other Performance F-bodies. The Lack of GFX was probably the biggest determiner of this, but there was other things, like my 87 did not have the rubber pieces on the bottom of the doors by the upholstery. Although you could option them up with creature comforts, Formulas were intended to be the stripped down Performance pony car of the era, intended to go head to head with the Mustang LX 5.0. I remember looking at an 88 Formula 350 with no options, no AC, no power locks/doors/cruise... this car was bare bones, the only option it had was a power antenna, which threw me. Looking back I wish I would have picked it up, but it was kind of beat.
So what triggered JG1 and N64 on the assembly line for Formulas? Any theories?
It was a 1988 only thing for the JG1 on the Formul... And it seems that all 350 cars got it that year at least on the Firebird side, 89 the JG1 went away on the Formula, so apparently it did not need it after 1988...
Keep in mind that 1988 was not quite as fuel efficient as the 1989 cars... There really was some minor changes from 1988 - 1989. For starters the colored dash went away which would not change the weight, but they stopped painting in front of the windshield black, and they stopped painting the lower air dams on the Base Firebird and Formula. On top of that they removed the 9th injector, added the rear seat seat belts. They also changed the routing of the Serpentine belts, I think 1989 is shorter but I am not sure (even though they used the same pulleys).
There may have been some other things going on insofar as making the cars lighter that I am not aware of... It is like the 4th gens, there are two different sets of mirrors. The early mirror is heavier than the later mirror, you can see the difference in thickness, but if you do not look you would never notice, and they might use the same GM part number. GM was gearing up for Airbags for 1990, so it would make sense to work on making the car lighter for 1989, so they did not have to do all the work and new tooling in 1990 only. Other things that changed thru the years is the early Formula scoop was cast Zink, someone told me the later scoop was plastic... These are all in an effort to lower the weight of the car to meet CAFE standards...
Does anyone know for sure that the Camaro was available with the JG1? It is not shown in the White book.
It was a 1988 only thing for the JG1 on the Formul... And it seems that all 350 cars got it that year at least on the Firebird side, 89 the JG1 went away on the Formula, so apparently it did not need it after 1988...
Keep in mind that 1988 was not quite as fuel efficient as the 1989 cars... There really was some minor changes from 1988 - 1989. For starters the colored dash went away which would not change the weight, but they stopped painting in front of the windshield black, and they stopped painting the lower air dams on the Base Firebird and Formula. On top of that they removed the 9th injector, added the rear seat seat belts. They also changed the routing of the Serpentine belts, I think 1989 is shorter but I am not sure (even though they used the same pulleys).
There may have been some other things going on insofar as making the cars lighter that I am not aware of... It is like the 4th gens, there are two different sets of mirrors. The early mirror is heavier than the later mirror, you can see the difference in thickness, but if you do not look you would never notice, and they might use the same GM part number. GM was gearing up for Airbags for 1990, so it would make sense to work on making the car lighter for 1989, so they did not have to do all the work and new tooling in 1990 only. Other things that changed thru the years is the early Formula scoop was cast Zink, someone told me the later scoop was plastic... These are all in an effort to lower the weight of the car to meet CAFE standards...
Does anyone know for sure that the Camaro was available with the JG1? It is not shown in the White book.
John
On Camaros, I've only seen it on heavily optioned IROCs..Always with auto and t-tops, and of course, non B4C 1LEs.
12-21-2018, 12:32 PM
