When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
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!
Don Keefe of Poncho Perfection is doing an article on my 1990 1LE Trans Am and has tasked me with getting together the information about the 1LE program, it's parts and the cars.
I would like to tap the knowledge base on this board in putting together the definitive statement on these special cars. What parts went into them, where they were sourced from, what were specifically developed for the program and which ones were "borrowed" from the parts bins. As the years went on & production of the third gens continued, which of these parts became running changes in production cars and which ones remained 1LE only.
To keep this from going all over the place, lets break it into 3 sections:
Brakes - front/rear
Suspension - struts, springs, bushings
Other - fuel tank/pickup, drive shaft, spare...
I want to make this public and write a piece that passes the acid test here on the board. I want the fans & the naysayers to agree on the facts so that we can dispel the myths that have long been carried in the press & hobby. Mark's most recent C10 brake findings are huge & I hope that in the next few weeks we can get others to pull part numbers off of their low mile original cars to help determine other parts.
Hopefully together we can correct the wrongs of the past but preserve the integrity of the program.
Is there such a thing as the 1LE spare? I had an 88 IROC that had the aluminum spare. My 91 1LE has a normal steel spare...
Also I don't think the fuel tank baffle was exclusive to the 1LE, possibly the early ones, but I think by 90/91 all cars came with a baffled fuel tank.
I'm kind of curious what kind of options you could have with the 1LE. Up until I bought my current car I was under the impression they were all zero option cars, but mine has a radio, power locks, and rear window defroster.
Is there such a thing as the 1LE spare? I had an 88 IROC that had the aluminum spare. My 91 1LE has a normal steel spare..
Have you checked that spare for rust or with a magnet? Prior to the PBR rear discs the aluminum spare is a cast 10 spoke, PBRs required additional clearance so GM came up with a 15" stamped aluminum spare, which they painted black. They look like a steel spare until you really look at them and notice there's no rust.
Re: 1LE suspension. I've spent more time researching thirdgen springs than possibly anyone on the planet. I've never seen a 1LE specific spring. What I have seen is that they use typical FE2 springs, often CDB springs in front. CDB springs can be found in Z28s at least as far back as 1984. Before that it gets a bit difficult to verify they're original equipment due to the lack of a SPID, but what it shows is that the springs were in inventory long before the 1LE existed.
Then you have other parts that went the other way, possibly developed for the 1LE program early on, or the 1LE program received the updated part first and then later the part was standardized on cars without 1LE. Examples of this would be the baffled tank, or the PBR rear disc brakes, and the "1LE spare". It's not really a 1LE spare, it's a PBR rear disc spare. "1LE A/C Delete boxes" aren't 1LE specific either, but putting that buzzword on their sure gets their attention on Ebay.
I think it may be important in the article to point out that when the 1LE was first offered, it was xxxxxxxxx, then as the years went on more and more of those parts trickled down into non-1LE optioned Z28s, Trans Ams, etc. Perhaps in your 3 sections, denote what years each part was 1LE specific so then readers know what year these parts trickled down into non-1LE vehicles.
Also of course point out that all TTAs and B4U Firehawks were 1LE as well, along with some B4Cs... a really in depth article would go into how 1LE accompanying options were allowed to be varied. For example, some could have AC and fog lights, power windows and CD player, etc. while others weren't depending on the year and model the 1LE option was selected for. There is a huge misconception that all 1LE cars were like stripper racers.
Were R7U cars 1LE as well?
Just a thought. Alex
EDIT: Maybe we could stop calling the gas tank "baffled" tank when it technically is not. A baffled tank has many walls inside it (like racing fuel cells), 1LE tanks just had a VERY basic small 4 walled plastic "box" around the fuel pump. When I looked into my 92GTAs tank I was disappointed to see what everyone had been referring to as a "baffled" tank lol. Call it "a tank baffle", not a "baffled tank" please.
I think it's generally agreed that 1LE parts were incorporated into regular production and that other cars ended up with them. What may have been special & unique to a 1LE car in 1988 had become standard production by 1992 for some of them - the gas tank and rear brakes in particular.
What I would like to know is what parts (specific numbers or rpo's) were developed and appeared on 1LE cars, were they brand new or borrowed from other cars and if/when did they go on to become standard production items.
For example - the drive shaft. I have read posts where owners have claimed they have an aluminum drive shaft on an 87 or 88 car but have not seen the RPO code - can anyone verify that? Same with the spare. These items became widely used afterwards to help meet CAFE requirements but were they used FIRST on the 1LE?
Brakes - we now know the front rotors were taken from the C10 and the calipers were NOT taken from the Corvette but were their own castings - did those part numbers remain consistent up through 1992? What about the back brakes - did they have their own casting numbers too or were they borrowed from another model?
Suspension - we've seen both 8NN/9NN and 8NL/9NL combinations on springs - Why? What were the other parts, bushings, control arms, end links that were used and then became standard production? Were there any real differences?
Like Drew & Alex have said, it's important that we get the terminology correct as well. If we can present a clear description of what these cars were without the confusing buzzwords we can begin to dispel the confusing myths and present the cars for what they were/are.
For example - the drive shaft. I have read posts where owners have claimed they have an aluminum drive shaft on an 87 or 88 car but have not seen the RPO code - can anyone verify that?
The P&I catalog doesn't list the JG1 shaft until 88. I am reasonably certain I've seen a few 88s with the aluminum shaft that weren't 1LEs. Seems to me that in 88 & 89 they used them often to save weight more than any performance advantage.
Brakes - we now know the front rotors were taken from the C10 and the calipers were NOT taken from the Corvette but were their own castings - did those part numbers remain consistent up through 1992? What about the back brakes - did they have their own casting numbers too or were they borrowed from another model?
I thought the front calipers were the same castings as the Corvette, just with the hose port machined in a different spot?
I've always been under the impression that GM went to PBR to solve the problems with the Delco-Moraine rear disc brake system. But I couldn't tell you exactly how I reached that assumption.
Suspension - we've seen both 8NN/9NN and 8NL/9NL combinations on springs - Why? What were the other parts, bushings, control arms, end links that were used and then became standard production? Were there any real differences?
The numbers in the spring codes denote the location they were used on the car. The actual spring codes for 8NN/9NN would be NNN, likewise 8NL/9NL were NNL springs. GM mixed and matched springs front to rear and right to left as they deemed necessary. Frequently you'll see right and left springs that are different from each other, as well as different fronts paired with the same rears on different cars. About all that GM tells us is that the springs are "computer selected". I'd like to think that means they run some huge calculation through the W.O.P.R. from Wargames, and Joshua has to tic-tac-toe out the best spring selection, but I would imagine the reality is much less entertaining and likely based on weight.
The NNN/NNL/CDB/BZwhatever springs date back to 1984 per the P&I catalog. Again, nothing special. NNN are actually a softer spring than the NNL/NNM springs typically used on FE2 cars.
Another note on springs... GM published charts showing how to replace springs with proper replacements. Often the service part for a block of springs (ex NNN/NNL/NNM) will be a single spring rated somewhere in the middle. The point being that GM didn't feel there was enough difference to keep 3 springs in inventory, when a single spring worked well enough that it wouldn't cause a problem.
I have lots of info to contribute, fact based on what I have on hand so to speak. I also have some info from the racing info. I've been trying to document my 89 1LE car - it's weird, but I think all early 1LE are that way. I also bet there is a non-1LE car that has all the key options that was suppose to trigger 1LE.
Let's add that GM used R7 options codes to bundle together different items. In all the 1LE cars I've documented, there is a trend in the R7F, R7K, R7N and so on.
There have been so many magazine articles published with 1LE info, but in my opinion, none of them are 100% correct. The combined knowledge on this forum has the answers and observations. So this will be quite an endeavor.
I have a memo from 1990 Race series which has some info. I'll scan and post. Basically the shocks and struts in 1990 R7U cars are production 1LE parts. As well the 1989 1LE gas tank and pickup is standard on all F-bodies.
I had an '88 5.7 iroc that was built with the aluminum spare and driveshaft. It was just a basic car with nothing really special about it, including the iron calipers and 2.77 gearing. It's been several years, but I should still have the rpo's written down somewhere.
I had an '88 5.7 iroc that was built with the aluminum spare and driveshaft. It was just a basic car with nothing really special about it, including the iron calipers and 2.77 gearing. It's been several years, but I should still have the rpo's written down somewhere.
My 1988 5.7 Iroc is much like your previous one described. Nicely optioned (for my taste anyway), but not a heavily optioned car. I've got the iron calipers, as well as the 2.77 gears too. Mine is also equipped with RPO #'s: JG1 shaft, prop, aluminum & N64 wheel & tire, spare, space saver, aluminum.
Don't know if this will be of any help with the 1LE facts, but my 1987 IROC 5.7 with T-tops doesn't have the JG1, does have the aluminum spare, N64 that looks like the steel one and is painted black,and J65 4 way disks and has the GW6 3.27 rear gears as stock equipment.
My 1988 5.7 GTA Notchback with leather and digital dash does have the JG1, the N64 aluminum spoked spare wheel still in the original plastic bag with directions for the installation, and GU6 (3.42) rear gears as stock equipment. This car is certainly the fastest of all my 3rd gen cars and has every option that could be ordered on it.
Last edited by yo soy el warg; 07-18-2016 at 02:04 PM.
This is all helpful information - thank you all. If you could, post up your SPID labels to show those codes.
As Drew has said, I don't believe the springs are specific to the 1LE package as both of my 91's have different ones & so do Erik's 91 & 92. My 91 Z28 has the 8NN/9NN springs as does his, but my 91 Formula has 8NL/9NL ones as does his 92 Z28. Unless some other evidence comes up, we should be able to rule those out as specific to the program.
It's interesting that the N64 Aluminum Spare made it's appearance prior to the introduction of the BW Aluminum Calipers - I'll need to spend some time with the parts books to see where/when that first showed up and how it was listed.
I did go through the parts book on the gas tank and the only 1LE specific part listed is the 3.110 STRAINER, FUEL SDR 89 25027354. The myth of the special dual swinging pickup may be able to die and if anyone has any experience with the tank box and how far back that goes, it would be useful.
My 1988 5.7 Iroc is much like your previous one described. Nicely optioned (for my taste anyway), but not a heavily optioned car. I've got the iron calipers, as well as the 2.77 gears too. Mine is also equipped with RPO #'s: JG1 shaft, prop, aluminum & N64 wheel & tire, spare, space saver, aluminum.
That just goes to show the challenge of this project. My one owner '88 5.7 IROC came with iron 2.77 discs but a steel driveshaft and the steel collapsible spare.
I'll post photos of the window sticker and the SPID later today.
GM just put the good stuff on seeming random cars... perhaps an issue with parts supply on the line??? Ran low on for example steel driveshafts so put in an aluminium one????
I remember working on a friends 86-87 TA years ago and it had a aluminum shaft, spoked spare and 16x8 crosslace wheels. Car was full of options and heavy. He was the 2nd owner and the rpo had JG1 on it.
That just goes to show the challenge of this project. My one owner '88 5.7 IROC came with iron 2.77 discs but a steel driveshaft and the steel collapsible spare.
I'll post photos of the window sticker and the SPID later today.
GM just put the good stuff on seeming random cars... perhaps an issue with parts supply on the line??? Ran low on for example steel driveshafts so put in an aluminium one????
Vehicle weight might have had something to do with it. Mine had t-tops and some power options, but it was far from being a full load car. Perhaps the t-tops option triggered the aluminum shaft and spoked spare? If yours is a t-tops car, then so much for that theory.
1LE Fact:
- The LB9 T5 had a 2.95:1 ratio first gear.
1LE Fiction:
- The first gear was 2.74:1 ratio.
This fallacy goes back years and is mentioned a few places in error for certain service tag T5 transmissions. Researching the service countershaft cluster gear and first speed gear for the supposed 2.74 first gear units, it's confirmed they used the exact same parts as the 2.95 first gear units. It's mechanically impossible to build a 2.74 first gear with Borg Warner or Tremec production parts.
I did go through the parts book on the gas tank and the only 1LE specific part listed is the 3.110 STRAINER, FUEL SDR 89 25027354.
Better double-check that... I haven't looked in the Camaro P&I yet, but just browsing the Firebird P&I, the 25027354 strainer is listed for 89 1LE, then it's listed again right below for 90-92 LH0, L03, LB9, and L98. It's also listed as the strainer for the 89 TTA, and 88-90 LB9, with no mention of 1LE.
It's worth noting that the P&I catalogs are for service parts. As such, the service replacement might not always be the exact part that was used on the assembly line. Things like clamps, or a part that has been superseded in the system may carry a different part number, or be a different part that works as a replacement even though it's not EXACTLY what was used OE.
1LE was a combination of options that varied year by year and some of those options were available outside of 1LE. The key is that the 1LE group was what was desired for the racing programs.
Transmission was not part of the 1LE package that I can find. I know the racing programs used the world class with the 0.73 OD. This was designated by two different option codes; MM5 and MK6 gave you the better OD ratio. This was the norm in all racing cars. I can't confirm if 1LE included this - but in all the RPO's I have seen, it was the case for the 5 speed cars.
Here is the information I can compile. Need confirmation from actual cars or paperwork. My info is either from actual cars, or racing documents.
1988 - unknown. Only a few examples to look at. A4U cars have info which lead up to the 1LE package.
1989 - 1LE package included (above the normal options included with Iroc-Z FE2 and Trans Am WS6) Both will have G92.
Camaro - 36mm front, 24mm rear sway bar. 12" 1LE brakes. Unique Front struts and rear shocks. Aluminum Drive shaft. Front/rear coils selected for "ride height". Rear Control Arms/Bushings. Gas tank with internal plastic reservoir and extended strainer.
Trans Am - Chassis Stiffener from Camaro, 12" 1LE brakes, Unique Front struts and rear shocks. Aluminum drive shaft. Front/rear coils selected for "ride height". Rear Control Arms/Bushings. Gas tank with internal plastic reservoir and extended strainer.
1990 - (short run up unto Dec 31 1989) - no data
1991 - Multiple Production Year run.
Some reference in racing docs that racing parts are now included in production 1LE package.
- improved crankcase ventilation
- camaro developed chassis stiffener and suspension bushings on Trans Am
- Camaro 1LE shocks and struts on Trans Am
- Revised rear axle control arm bushings to reduce axle hop
- flow checked fuel injectors.
*** Gas tank now standard on all F-bodies ***
Camaro - 36mm front, 23mm rear sway bar. 12" 1LE brakes. Front Struts and Rear Shocks now 1LE part numbers. Aluminum Drive shaft. Front/rear coils selected for "ride height".
Trans Am - 23mm rear sway bar. Chassis Stiffener from Camaro, 12" 1LE brakes, Front Struts and Rear Shocks now 1LE part numbers. Aluminum drive shaft. Front/rear coils selected for "ride height".
1991 Second run in 1991
*** notes that the camaro front chassis stiffener is removed ***
1992 - no data yet.
Part Numbers
Front brake rotors as supplied on cars:
1988, 1989 - casting number 14008647
1991 casting number 18016211
1LE replacement part 18016035 (unsure what casting number is)
Front Struts as delivered.
*** 1LE part number is 22064153 - racing notes say struts are the same, only part numbers are different ***
1988 - ?
1989 - 22074399 (Trans Am may have had different ones)
The Camaro P&I fuel tank/sender chart shows the 1LE tank becoming the standard tank in 1990. In 88 & 89 the 1LE tank is 10121026, the standard tank (LB8, L03, LB9, L98) was 10042327. They also show two different senders - 1LE: 25094804 vs 25027221 for everything else aside from the L03. Then in 1990 25094804 becomes the standard sender for the LB9/L98, while the 3.1 still used the 7221 sender.
The strainer section is a head scratcher... The list doesn't show a strainer for an 88-89 LB9/L98 in a Z28 1LE. There's a listing "(exc Z28)" which probably should have said "exc 1LE". 25027354 is listed for 88-89 w/1LE. Then 90-92 the 25027354 strainer is listed for everything.
So to recap... 88-89 1LE - specific tank, sender, and fuel strainer. 90-92 - everything used the 1LE tank, and the 1LE strainer. The 90-92 LB9/L98 used the 1LE sender.
Re: Aluminum spares...
Earliest I've seen the 10 spoke aluminum spare is 1985, usually on the Trans Am.
I've always assumed, based on what I've seen, that the black painted - stamped aluminum inflate-o-spare came around with the advent of the PBR discs in back. The 10-spoke aluminum spare will not fit.
The P&I catalogs aren't much help with spares from what I've seen. They refer to a service bulletin and servicing the inflate-o-spares direct from source.
Fun Fact #271: Did you know that the stamped aluminum inflate-o-spare is a 15" wheel vs the 14" 10-spoke cast aluminum wheel? Also the inflator cans are different between the early and late Aluminum spare, the 15" version is a couple inches taller with a larger volume. *insert the more you know jingle and shooting star here*
I have pictures of the spare from a 1989 R7U car, which I assume is the same as the 1LE cars. Basic black wheel, but made from aluminum. I have pics with the inflator can and part numbers on rim.
I never thought about the fitting over the rear brakes ... always though it was the front caliper.
In the 1988 Race season, the 1988 cars came with 1LE front brakes ... notes from GM engineers said spare tires designed to fit over the brakes were coming later. Too bad racing teams didn't keep things like spare tires. Not much to go on.
I've got a few pics I took while rebuilding the correct jack/spare combos in my cars. Seems like those pieces tend to get lost along the way for whatever reason...
The 10-spoke inflate-o-spare, in my 87 Iroc. Not a 1LE part.
The stamped aluminum 15" inflate-o-spare in my 91 Formula. This is the 1LE version.
In this pic, the smaller inflator that matches the Iroc spare is strapped to the 15" spare. What clued me to there being two different inflators used was that regardless where I mounted the inflator, it didn't match the rub marks from the missing can. The correct can, which I can't find a photo of at the moment, spans almost completely from one side of the rim to the other.
The History/Originality section needs a wiki page where we can actively update and document thirdgen history with reference materials and photos. Right now, most of the information is scattered about posts, what's incorrect vs. correct is hard to determine, and some people have great documentation and original reference cars just sitting in garages and bookshelves. Is a wiki page possible with the current board setup?
My 1988 5.7 Iroc is much like your previous one described. Nicely optioned (for my taste anyway), but not a heavily optioned car. I've got the iron calipers, as well as the 2.77 gears too. Mine is also equipped with RPO #'s: JG1 shaft, prop, aluminum & N64 wheel & tire, spare, space saver, aluminum.
the 88 formula I had was a aluminum driveshaft car, spoked aluminum spare, 305 tpi 3.23 posi rear drum with T-tops
good friends 88 GTA 305 tpi t-top had the steel drivehaft but had the factory PBR rear discs but iron front calipers
my 89 formula 350 of course had the pbr rear calipers and the aluminum spare the looked like a steel wheel. steel driveshaft is a hard top
had a 88 formula 305 tpi 5-speed with the 3.45 9 bolt iron rear calipers steel driveshaft regular steel spare. hardtop
Mark - great work but what are the chassis stiffeners? Could you also include your info on the other thread regarding the rotors sourced from the C10 program and the differences in the front calipers from the Vette?
Drew - Thank you for your detailed fuel tank breakdown but I believe you mis-understood my comment. Unfortunately my parts book is from 1992 and in that the only 1LE specific part I could find listed was the strainer - that's all.
I agree with you on your aluminum spare details as I had always believed the 1LE one was visually like the stamped steel one and was not the spoked one. Can anyone provide a SPID with N64 on it earlier than 88/89 and specifically a non 1LE N64 SPID?
For those of you contributing on cars that contained some of the parts early on - could you please post a picture of your SPID for them? Many of these parts were shared across the lines - some for no reason it would seem - it would be helpful if we could show at what point they were introduced.
1LE Fact:
- The LB9 T5 had a 2.95:1 ratio first gear.
1LE Fiction:
- The first gear was 2.74:1 ratio.
This fallacy goes back years and is mentioned a few places in error for certain service tag T5 transmissions. Researching the service countershaft cluster gear and first speed gear for the supposed 2.74 first gear units, it's confirmed they used the exact same parts as the 2.95 first gear units. It's mechanically impossible to build a 2.74 first gear with Borg Warner or Tremec production parts.
I had never heard that the 1st gear was different in the M39 vs the MK6, the 5th gear is different however.
Mark - great work but what are the chassis stiffeners? Could you also include your info on the other thread regarding the rotors sourced from the C10 program and the differences in the front calipers from the Vette?
The Chassis stiffener is the "wonderbar". Also called Front rail reinforcement. The 1LE package made the Camaro and Firebird the same so to speak.
The C10 rotor is a new bit of info. Various sources said the rotor came from a Caprice, which I believe to be true. The stories I heard are that the first prototypes had the smaller bolts drilled into the stock caprice rotors. I could see this for a quick prototype, but not for competition. The letters from 1986 said the Saginaw provided the steering knuckle and disc brakes in just 9 days. These were the Brembo capliper ones, but same rotors. I'll check with the fellow who has the 1986 Player's car and see what casting number he has on the 1986/87 parts. These would be the true prototype of the 1LE setup.
The rumored 2.75 MK6 1st gear is even in GM's own literature. I suspect it was a misprint and then picked up by various magazines of the day - and then became psuedo-fact.
That's great Drew - so if the N64 spare was developed in conjunction with the BW aluminum brakes does that tell us that program was in the works prior to 1987? Or does this tell us the N64 pre-dated the BW brake program?
Was this the spoked wheel or the black one? Was N64 used for both?
From what Mark said above the correct spare wasn't available as late as 1988 for the early R7U cars.
I've got a few pics I took while rebuilding the correct jack/spare combos in my cars. Seems like those pieces tend to get lost along the way for whatever reason...
The stamped aluminum 15" inflate-o-spare in my 91 Formula. This is the 1LE version.
My 90 non 1LE spare looks like this. Are there subtle differences?
My 90 non 1LE spare looks like this. Are there subtle differences?
No, the "1LE spare" is just the PBR rear disc spare. It just so happens that 1LEs had the PBR rear discs. People have incorrectly linked the aluminum spare to 1LE, when the relationship is purely coincidental.
N64 predates the 1LE program. The N64 code applies to BOTH the 10-spoke aluminum and stamped aluminum spares.
Further evidence that the N64 spare follows the PBR rear discs is evidenced in the following SPIDs. Note that one is my 1991 Formula L98, the other is another 1991 Formula LB9/5spd that no longer exists. The 5spd car was built during the PBR shortage. Note that it came with the N65 steel spare rather than the aluminum spare, since it was built as a drum brake car.
is there anything special about a 92 rs 1le , b4c camaro ?
RS body and usually interior paired with the Z28 drivetrain, gauge cluster, suspension. The 1LE code is just for the dual piston front brakes. The P&I catalog shows that everything else on the B4C/1LE was the same as a standard L98 Z28 of the same year.
No, the "1LE spare" is just the PBR rear disc spare. It just so happens that 1LEs had the PBR rear discs. People have incorrectly linked the aluminum spare to 1LE, when the relationship is purely coincidental.
N64 predates the 1LE program. The N64 code applies to BOTH the 10-spoke aluminum and stamped aluminum spares.
Further evidence that the N64 spare follows the PBR rear discs is evidenced in the following SPIDs. Note that one is my 1991 Formula L98, the other is another 1991 Formula LB9/5spd that no longer exists. The 5spd car was built during the PBR shortage. Note that it came with the N65 steel spare rather than the aluminum spare, since it was built as a drum brake car.
True. My PBR equipped G92 has the N64 spare. Strangely, I just looked at a pic of my '89 convertible's SPID on my phone and have no code for a spare. I was expecting to see N65. I'll need to look at that when I get home.
The SPID for my old 91 6cyl Firebird doesn't have N64 or N65. I suspect there's a code on there somewhere for a spare, but it doesn't jump right out at me and I'm not terribly interested in decoding all it's RPO codes for something that's not too important. Couldn't tell you what my V6 came with anyway, since the spare was gone when I got it - it was a basket case. I'm currently holding on another 91 bird basket case, but it has neither a spare or a SPID. LOL The things we do "for fun".
No, the "1LE spare" is just the PBR rear disc spare. It just so happens that 1LEs had the PBR rear discs. People have incorrectly linked the aluminum spare to 1LE, when the relationship is purely coincidental.
N64 predates the 1LE program. The N64 code applies to BOTH the 10-spoke aluminum and stamped aluminum spares.
Further evidence that the N64 spare follows the PBR rear discs is evidenced in the following SPIDs. Note that one is my 1991 Formula L98, the other is another 1991 Formula LB9/5spd that no longer exists. The 5spd car was built during the PBR shortage. Note that it came with the N65 steel spare rather than the aluminum spare, since it was built as a drum brake car.
My 90 Formula has the N64 stamped aluminum spare, but does not have PBR rear disks. It came with drums. I haven't verified it is aluminum, but have verified the N64 RPO. Maybe it is part of the performance suspension package, rather than linked to rear brake type.
I'm also thinking the coil springs are related to what is hanging on the car (weight related) A/C, body skirts, ect..... Thus, computer selected.
Last edited by LiquidBlue; 07-18-2016 at 02:20 PM.
The SPID for my old 91 6cyl Firebird doesn't have N64 or N65. I suspect there's a code on there somewhere for a spare, but it doesn't jump right out at me and I'm not terribly interested in decoding all it's RPO codes for something that's not too important. Couldn't tell you what my V6 came with anyway, since the spare was gone when I got it - it was a basket case. I'm currently holding on another 91 bird basket case, but it has neither a spare or a SPID. LOL The things we do "for fun".
Any idea on what other codes denote a spare? I'm not aware of any others.
Question,
I was talking to a friend about a Grand National that was driving by our car. He told me that it amazed him that the GN did not get the bigger brake option that was available on the SS Monte Carlo. The reason I bring this up, I have heard before they borrowed the brakes from the Caprice, but the Caprice has a 5x5.5" Bolt Pattern, but the G-body and the F-body had the 5x4.75" bolt pattern. The Corvette we have recently discovered that the calipers are actually a little different I thought. Someone please set me straight.
My 90 Formula has the N64 stamped aluminum spare, but does not have PBR rear disks. It came with drums. I haven't verified it is aluminum, but have verified the N64 RPO. Maybe it is part of the performance suspension package, rather than linked to rear brake type.
I would imagine that since weight seems to trigger aluminum items and option deletes - i.e. weight savings, that it may simply be that the computer decided the car should be built with the only aluminum spare available at that time, to save weight more than to clear the brakes.
From what I've seen, G80 cars usually have an inflatable spare that inflates to the same or very similar outside diameter as a full size wheel/tire combo, to prevent lunching the limited slip differential.
You get the aluminum spare to save weight, and the larger aluminum spare when the car was built with PBR rear discs.
Originally Posted by chazman
Any idea on what other codes denote a spare? I'm not aware of any others.
I'd imagine it'd be a N?? or P?? code. Might look at the Q?? codes too. If I get a chance later I'll look into it a bit closer.
Did the 10 spoke go away at the advent of the PBR rears going into standard production? Why have two aluminum spares when one will do - right?
So Drew, the 1987 N64 SPID is a 10 spoke?
That is the way I interpret the data I've seen, yes. By all means, feel free to research and ask around for a second opinion, but that's the way I see it, FWIW.
In 1987 I believe the N64 rpo code refers to the 10-spoke aluminum wheel. In the interest of not corrupting the data set, I'll be honest, the spare was MIA when I got the car, along with most of the jack hardware. It did have the plastic spacer saddle that supports the 10-spoke inflate-o-spare inside the 1/4 panel. It'd be easy enough for Scott or one of the other low mile 87 L98 Iroc folks to verify which spare they have.
Originally Posted by LiquidBlue
I'm confused, are there 2 different 1LE aluminum spares? 2 different sizes?
This is my N64 :
Yes, and No. There are two different ALUMINUM spares. A 14" 10-spoke used from about 85-88 or 89, and there's a 15" stamped aluminum spare that was painted black and looks like a steel spare, minus the rust. The larger aluminum spare was used on the later cars, but I haven't looked into the exact year it came into service. Both spares were RPO N64 spares.
N65 is a steel spare. There were other steel spares like the mini-spares that were always inflated.
I dunno guys. It looks to me that all GM was doing was looking for cost saving measures. Having two part numbers is more expensive than one and those 14" spokes were probably more expensive than stamped aluminum and also probably helped reduce weight to keep gas mileage in check for Fed Regs.
If I had to guess, there was not an option code besides N64 or N65. The donut spare used on non-posi cars would be the standard spare, not requiring an option code, correct?
And this is the first I've ever heard of a big brake option on a Monte SS. As far as I know, they all used the same disc and drum brake setup that the F-body and S-10 got. And the Caprice bolt pattern is 5x5 btw.
07-16-2016, 06:51 AM
