I've been trying to pin down OEM IROC spring rates without much sucess. From an 85 Camaro Parts Specification book from GM(though there is no mention of IROCs), I found the following:

Suspension, Front--spring rate (lb/in): L4 & V6, 331.0 lb/in; V8 & F41, 365.0 lb/in; Z28, 548 lb/in.

Suspension, Rear--spring rate (lb/in): 103 lb/in, exc Z28, 131.5 lb/in.

Here's the original thread:

https://www.thirdgen.org/forums/susp...ring-rate.html

I'd welcome any info.

JamesC

The listing for V8 and F41 show 365#. The only other V8 offering was the stiffer FE2 suspension, which I would think to be the Z28 listing. Remember, the IROC-Z is a Z28, so the higher spring rate would be for the IROC-Z also. The only time it would be less, is if the Z28 had the F41 RPO code.

So it would appear that replacement springs for IROCs aren't close to OEM specs.

JamesC

Keep in mind that each car may have different springs depending on the options ordered. I know for a fact that if you have AC delete you will have different springs than with AC. If you look at your SPID sheet you will find that there is an RPO for "Computer selected spring" This basically is telling you that with your options you got spring (Add RPO here)

As for meeting GM specs, the only way you will get anything exact is to find a similar car in a junkyard and pull the springs from that. Also keep in mind that Pontiac springs are softer for a better ride, but the sway bars are larger on the WS6 cars than on the Z28 or IROC to offset the softer springs. It was more about ride, the IROC rides harder the T/A rides softer, engeneers designed them that way for a reason.

To go even further you can conclude that the 1LE cars had the springs from the Camaro, the Wonder bar from the Camaro, but the sway bars from the WS6 Trans Am...

John

To back up what okfoz said I broke out my dealership parts book. The spring options were broken down by year, engine, and suspension RPO(WS6, Y99, etc). So Irocs from the same year might have different springs depending on other options. I haven't found spring rate numbers yet, the spings in the catalog are listed simply in order lowest to highest rate. Do you have the RPO codes for your springs James? Mine were BZW up front and NNL rear.

Moog catalog shows many different springs available with the stiffest being either in 91 Formula or GTA and around 7XX lbs/in.

Well, this gets to the heart of what I was really searching for: Replacement springs for BYZ fronts (14029300, I think) and NNM rears (10018092, again, I believe).

JamesC

I polled thirdgen owners for their spring codes and got about 40 responses. Any V8 car could have the same exact springs as an Iroc, Z28, or 1LE. Some 92 Z28's had the same codes as F41 optioned 84 Coupes. Some cars like the 86 Firebird I parted out a few years back have the exact same codes as a few 91 1LE's that replied.

As for the rates? anyone's guess.

The Tag on the Spring or the RPO code on the SPID sheet??? I am not sure if they are the same Code or not, I would assume they were, but they may not be.

If they are different then you would ahve to go with the decal on the spring.

John

To add. Looking at a GM parts book from MAy 1989, they listed two groupings of springs. The first was for suspension FE1, the other was for FE2 and F41. The first listing had part numbers from 14029386-14029393 (codes BXK-BXW), and the second had 14029394-14029400 (codes BXX-BZZ). The rears were broken down the same. Basically all the springs had 3 letter codes.

The make, model, and options dictated what springs a car got. For the Player's racing series, GM allowed teams to change the springs but they had to meet a minimum ride height.

I'm not sure these numbers are still valid or not. Chances are they change up to a single replacement for FE1, FE2 and F41.

If anyone wants to see the list, let me know and I will post it.

Mark.

The more info, the better.

JamesC

The codes on the springs are different then the RPO codes... the tags will say BZW or BZX or whatever, and the RPO sheet will show 6ZW 6ZX or 7ZX or 7ZW. The numbers indicate position, 6 and 7 are the front, left and right, 8 and 9 are the rear, left and right.

A typical WS6, Z28, Iroc, etc will have BZW or BZX springs in the front and NNM or NNN in the rear. Some cars have mismatched front springs, although I never did figure out the logic behind it. The best part was seeing that a 1984 Trans Am could have the same exact spring codes as a 1992 Z28 1LE, pretty much disproving that 1LE cars had 'special' springs.

From the information I was able to compile, the spring gets stiffer as the final letter goes up. ie a BZX is stiffer then BZW, NNN is stiffer then NNM, and so on.

BZW, BZX, BZY, BZZ, would all be typical high performance front springs.
NNL, NNM, NNN, would be typical high performance rear springs.

Most V8's will have codes within about 3 letters of each other. V6 and I4 cars have codes that are far removed from the V8 cars.

Attached is a chart that someone posted at some point, fwiw.
And for fun, here's my notes on all the spring codes from various cars that thirdgen.org members submitted to me while I was compiling...

6DA : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 84 FBIRD V6
7WY : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 84 FBIRD V6
8UZ : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 84 FBIRD V6
9UZ : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 84 FBIRD V6
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 84 Z28
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 84 Z28
8NN : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 84 Z28
9NN : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 84 Z28
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1984 H.O. Z28
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1984 H.O. Z28
8NN : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1984 H.O. Z28
9NN : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1984 H.O. Z28
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1984 LG4 Z28
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1984 LG4 Z28
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1984 LG4 Z28
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1984 LG4 Z28
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 84TA no WS6
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 84TA no WS6
8NM : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 84TA no WS6
9NM : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 84TA no WS6
8WA : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 84 T/A L69 WS6
9WA : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 84 T/A L69 WS6
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 85 Iroc FE2
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 85 Iroc FE2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 85 Iroc FE2
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 85 Iroc FE2
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 86TA WS6 LB9
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 86TA WS6 LB9
8NB : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 86TA WS6 LB9
9NB : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 86TA WS6 LB9
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 86TA WS6
7DB : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 86TA WS6
8NB : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 86TA WS6
9NB : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 86TA Ws6
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 86 Z28 FE2
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 86 Z28 FE2
8NM : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 86 Z28 FE2
9NM : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 86 Z28 FE2
6DB : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1986 H.O. IROC
7DB : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1986 H.O. IROC
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1986 H.O. IROC
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1986 H.O. IROC
BZX : Fronts, 87ish WS6 T/A
NNB : Rears, 87ish WS6 T/A
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 87 Iroc
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 87 Iroc
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 87 Iroc
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 87 Iroc
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 87 Iroc #2
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 87 Iroc #2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 87 Iroc #2
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 87 Iroc #2
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1987 LG4 Z28
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1987 LG4 Z28
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1987 LG4 Z28
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1987 LG4 Z28
6DB : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1987 L98 IROC
7DB : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1987 L98 IROC
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1987 L98 IROC
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1987 L98 IROC
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1987 LB9 IROC
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1987 LB9 IROC
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1987 LB9 IROC
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1987 LB9 IROC
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 87 Formula L98 WS6 FE2
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 87 Formula L98 WS6 FE2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 87 Formula L98 WS6 FE2
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 87 Formula L98 WS6 FE2
6XW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 88 CAMARO SPORTCOUPE LO3
7XW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 88 CAMARO SPORTCOUPE LO3
8UX : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 88 CAMARO SPORTCOUPE LO3
9UX : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 88 CAMARO SPORTCOUPE LO3
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 88 Iroc
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 88 Iroc
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 88 Iroc
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 88 Iroc
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 89 Iroc
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 89 Iroc
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 89 Iroc
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 89 Iroc
6XU : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1989 L03 RS
7XU : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1989 L03 RS
8UY : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1989 L03 RS
9UY : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1989 L03 RS
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1989 L98 IROC
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1989 L98 IROC
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1989 L98 IROC
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1989 L98 IROC
6DB : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1989 LB9 IROC 1LE
7DB : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1989 LB9 IROC 1LE
8NN : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1989 LB9 IROC 1LE
9NN : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1989 LB9 IROC 1LE
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 90 IROC FE2
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 90 IROC FE2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 90 IROC FE2
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 90 IROC FE2
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1990 L98 IROC
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1990 L98 IROC
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1990 L98 IROC
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1990 L98 IROC
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 90 IROC FE2 L98
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 90 IROC FE2 L98
8NN : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 90 IROC FE2 L98
9NN : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 90 IROC FE2 L98
6XW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1990 L03 RS
7XW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1990 L03 RS
8UZ : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1990 L03 RS
9UZ : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1990 L03 RS
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 91 formula FE2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 91 formula FE2
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 91 formula FE2
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 91 formula FE2
6XS : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 91 fbird V6
7XS : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 91 fbird V6
8UY : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 91 fbird v6
9UY : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 91 fbird v6
6XU : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 91RS F41
7XU : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 91RS F41
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 91RS F41
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 91RS F41
6XY : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 91Z28 convertible LB9 5spd FE2
7XY : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 91Z28 convertible LB9 5spd FE2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 91Z28 convertible LB9 5spd FE2
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 91Z28 convertible LB9 5spd FE2
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 91Z28 convertible FE2
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 91Z28 convertible FE2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 91Z28 convertible FE2
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 91Z28 convertible FE2
6XW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 91RS Convertible F41
7XW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 91RS Convertible F41
8NM : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 91RS Convertible F41
9NM : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 91RS Convertible F41
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 91Z28
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 91Z28
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 91Z28
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 91Z28
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 91 GTA
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 91 GTA
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 91 GTA
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 91 GTA
6DB : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 91 Z28 1LE
7DB : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 91 Z28 1LE
8NN : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 91 Z28 1LE
9NN : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 91 Z28 1LE
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92 GTA
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92 GTA
8NM : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92 GTA
9NM : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92 GTA
6XU : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92Z28 Convertible F41
7XU : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92Z28 Convertible F41
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92Z28 Convertible F41
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92Z28 Convertible F41
6XU : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92RS F41
7XU : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92RS F41
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92RS F41
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92RS F41
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92 T/A WS6 LB9
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92 T/A WS6 LB9
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92 T/A WS6 LB9
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92 T/A WS6 LB9
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92 GTA #2
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92 GTA #2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92 GTA #2
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92 GTA #2
6XT : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92 z28 Convertible F41 #2
7XT : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92 z28 Convertible F41 #2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92 z28 Convertible F41 #2
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92 z28 Convertible F41 #2
6XU : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92 L03 RS(F41)
7XU : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92 L03 RS(F41)
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92 L03 RS(F41)
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92 L03 RS(F41)
6XW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92 L03 RS Conv(F41)
7XW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92 L03 RS Conv(F41)
8NM : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92 L03 RS Conv(F41)
9NM : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92 L03 RS Conv(F41)
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92 L98 Z28
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92 L98 Z28
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92 L98 Z28
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92 L98 Z28
6XW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 92 L03 RS(FE1)
7XW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 92 L03 RS(FE1)
8UZ : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 92 L03 RS(FE1)
9UZ : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 92 L03 RS(FE1)
6ZW : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1992 L98 RS(B4C)
7ZW : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1992 L98 RS(B4C)
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1992 L98 RS(B4C)
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1992 L98 RS(B4C)
6XT : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 1992 LH0 RS(FE1)
7XT : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 1992 LH0 RS(FE1)
8UZ : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 1992 LH0 RS(FE1)
9UZ : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 1992 LH0 RS(FE1)

Here are the springs from 1988. I have the 1989 listing, but not scanned.



Mark.

Thanks for the posts. I'm trying to soften the ride on my WS6, and lower it a bit, but keep as much handling as I can.

So please clarify. The code wording is kinda funny here.

• FE1 is "Soft ride." Soft springs and soft bars?
• FE2 is "Ride Handling." Kinda cryptic. Soft springs and stiffer bars? A compromise setup between FE1 and F41?
• F41 is "Front, Rear, Firm ride, Handling." So this is the street performance setup? Roughly equivalent to my WS6? (On mine, "Firm" is an understatement.) Why does this say "Front, Rear?" Are other systems not the same front and back?
• 1LE is "Performance Suspension, Showroom Stock Racing." No doubt, really stiff springs and bars, right? Harsh ride. Drives like it's on a rail. Not really made for the street, though some guys want it that way? As harsh as mine rides, I wonder if the "Performance Suspension" placard on the right end of my dash isn't something like this?

Any indication on how these correspond to Firebird RPO's?

My 'Bird's RPO sticker was long missing when I got the car. I'm gonna have to contact (and pay) one of those services that traces your car by VIN, I guess. I only determined it's a Formula with WS6 by physical examination of the whole car. Does the "Performance Suspension" placard on the right end of the dash mean anything more than standard WS6? If so, maybe I should leave it alone and live with the ride, for value's sake?

If I am reading the cart correctly the part numbers to the top of each section ahve the Highest Load rate, the numbers at the bottom have the lowest load rate. I would think you want a lower load rate. The FE1 is softer than FE2, F41 & obvously the 1LE is all performance...

But you must realize that F41 with a V6 is the same springs as the base springs with a V8, so they are probably the softest. I would think you want something in the Top right box.

John

FE1 is the softest suspension offered.
F41 is the mid-level
FE2 would be Iroc or WS6 spec

1LE cars should all be FE2 cars. When you look at the actual codes listed above and comparing to other non-1LE cars, you'll see that at least when dealing with springs, there's nothing special about the 1LE.

The 'Performance Suspension' tag can mean F41 or FE2, but since it was a $5 emblem from the dealers that was available up until a few years back, it's not a guarentee of anything.

If you want to make your car ride softer, don't even bother with trying to change the springs. There isn't enough difference between one and another that you'd really be able to tell. You'd probably have better luck buying some good struts and quality shocks.

They didn't make this easy on us, did they?

But you answered one of my nagging questions. Based on the total package that I find under the car, and the feel of the ride, then I've got about the stiffest available. Now that I've got some numbers and know where to look, I'll slide under and see if the springs still have their markings or tags on them.

Define "good struts and quality shocks." Are you talking something like Bilstein or Koni or KYB? When I replaced shocks/struts a few years back, I had to make a compromise. I didn't get the best (too much for my budget), but I didn't go cheap either. I've got Monroe Sensa-Tracs all the way around. Got a major improvement over what was in there at the time.

THe Bilstein, Koni and KYB will ride harder than the Sensa-Tracks (from my experience)...

What you might consider is get a set of shocks for a firebird S/E. They were target to be the Luxury model, I would imagine they had the softest of the shocks. The Trans Am I would suspect would have stiffer shocks.

John

I have the original RPO sticker in the console and have the spring tags still on the springs that match the RPO. They are 6DB and 7DB (front) and 8NN and 9NN (rear). The RPO says FE2 and 1LE. I ordered the stock shocks from a dealer using my VIN and they were very reasonable. It rides much better and I do enjoy taking it out occasionally on the street. It was about $200 for all four.
As Drew said there isn't too much different about the 1LE from a regular IROC, except for fog lights and AC delete.

Randy

Also, my 1990 Specification Book lists the same spring rates as JamesC listed for 85. 548 front and 131.5 rear.

Randy

So then does anyone have GM part numbers for the rear springs? Looking for NNL in particular. I feel guilty calling a dealer for part numbers when I buy from GMPartsDirect.com.

what will happen if i put V8 springs on a V6 car and vice versa ???

Since the V6 would be lighter V8 springs would make the front of the car ride higher. The rear of the car would not change since the engine is in the front of the car. If you put V6 springs in a V8 car obvously the front would ride lower since the V8 is heavier.


How much is hard to determine... It could be as much as 2 inches or it could be as little as a half of an inch change. WIthout digin the math and figuring it all out or just trying it.

JOhn

thanx for the answer,but i was thinkin what could happen on the ride feeling and stability
and is a right hand spring different than the left one ?