Thirdgen spring codes
12-06-2009, 08:41 PM
#1
Thirdgen spring codes
This comes up from time to time. Someone states a car can be identified as a WS6, IROCZ, 1LE, etc by the spring codes. Several years ago I collected codes from 20-50 cars and started comparing the data to determine if there was any consistent trend. At the time, the conclusion that I reached was that the codes on the springs had very little to do with the model of the car. In reality the codes have more to do with the engine and suspension level.
GM typically used 3 levels of suspension on 82-92 Camaros and Firebirds. Level I is standard on the 4 cylinders, and 6 cylinders, and some base model V8s. RPO FE1 is an example of a level I suspension, but some early cars may have a different RPO code. Level II was optional on some 6 cylinders, and V8s, some of the entry level performance cars, like Z28s and non-WS6 Trans Ams, etc. Level II is usually identified as RPO F41. Level III was reserved for the top end cars. The RPO code FE2 indicates a level III suspension. I'm fuzzy on early car specifics, so maybe someone can step in and explain where Y99, WY5, WY6, etc fit in here.
Anyway, tonight I was browsing http://www.compnine.com and I was looking at the spring charts. I'd seen a couple snips of these charts before, but never the full picture from 82-92 for both the Camaro and the Firebird. The Camaro chart can be seen here http://www.compnine.com/chart.php?num=46155 and the Firebird chart here http://www.compnine.com/chart.php?num=46558 . The first thing that stands out is this paragraph of instructions on the second page...
What this tells us, is how the RPO codes tell us the location of said spring, and it's spring rate. This is the translation from 6ZW to BZW or 7ZX to BZX. It's explaining that the B in the broadcast code is a place holder as much as anything else.
It also tells us that there isn't enough difference between a BZX and a BZW to really be noticed. Notice it says if in doubt shoot for something in the middle. If there was really a 1" height difference to be found between springs, obviously this shoot from the hip policy could cause problems.
Then as we continue to look at the charts, the spring codes are listed under headings that explain which cars came with which springs. Notice that the codes that determine which springs should be used deal with
-suspension level, i.e. WS6, FE2, F41, Y99, Z28, etc.
-engine, i.e. LH0, LB9, L98, LG4, LU5, etc.
-tires, i.e. QYC, QLC, QAC, etc.
Next, what we see is the spring codes and part numbers rated from highest load rate, down to lowest load rate. What this tells us is that ANY of a handful of springs can be considered correct for certain combinations. For example, A 1992 WS6 Firebird could have BZY, BZX, BZW, CDB, or BXY front springs from the factory. We see this almost identical selection of springs as being available on a 1984 Z28, or a 1984 WS6 Firebird. This shows us that the late model "special springs" as would be found on a 1LE, or WS6 Firebird, or G92 Z28, or IROCZ, are the same as a basic 1984 L69 Z28 or Trans Am WS6.
To drive the final spike into the heart of the "special spring" myth, note that the service numbers for replacing several springs are the same part number. Obviously if there was such a great difference between one spring and another, the replacements would be much more specific then one size fits all.
So what does this mean? It means if you have a V8 with an FE2 suspension, you probably don't have much to gain by swapping to "Iroc springs" or "1LE springs" or "WS6 springs". It means that the springs codes don't really tell you much about a car.
GM typically used 3 levels of suspension on 82-92 Camaros and Firebirds. Level I is standard on the 4 cylinders, and 6 cylinders, and some base model V8s. RPO FE1 is an example of a level I suspension, but some early cars may have a different RPO code. Level II was optional on some 6 cylinders, and V8s, some of the entry level performance cars, like Z28s and non-WS6 Trans Ams, etc. Level II is usually identified as RPO F41. Level III was reserved for the top end cars. The RPO code FE2 indicates a level III suspension. I'm fuzzy on early car specifics, so maybe someone can step in and explain where Y99, WY5, WY6, etc fit in here.
Anyway, tonight I was browsing http://www.compnine.com and I was looking at the spring charts. I'd seen a couple snips of these charts before, but never the full picture from 82-92 for both the Camaro and the Firebird. The Camaro chart can be seen here http://www.compnine.com/chart.php?num=46155 and the Firebird chart here http://www.compnine.com/chart.php?num=46558 . The first thing that stands out is this paragraph of instructions on the second page...
SPRING CHARTS
TO UTILIZE THE SPRING CHARTS, THE FOLLOWING STEPS SHOULD BE
USED:
1. OBTAIN THE SPRING CODES FROM TAGS ON ORIGINAL SPRING
OR FROM THE "SERVICE IDENTIFICATION LABEL" LOCATED ON
THE VEHICLE (SEE INFORMATION IN FRONT OF CATALOG FOR
EXACT LOCATION OF "SERVICE IDENTIFICATION LABEL"). THE
S.P.I. LABEL EXAMPLE SHOWN BELOW HAS THE FOLLOWING SPRING
CODES 65C,7SB,8WT,9WT.
S.P.I. LABEL U.S. AND CANADA
1 G 1 B N 6 9 H X E 5 1 0 0 0 0 1
C90 C95 DF3 D3C D33 D08 E5Z E7D FFL F40 GG1 GW9 G60 GU2 G89
JA1 JA4 K05 K22 K99 LV2 WW9 WX0 NA5 N81 NK1 NK3 N33 N67 GLW
T87 UJ3 U23 U35 V08 V10 WC3 WG2 YT9 Y56 01L 6SC 42B 42I 42Q
42T 409 7SB 8WT 9WT 11A 90A
NOTE: THE FIRST DIGIT DENOTES SPRING LOCATION, I.E.
6 = LH FRONT 8 = LH REAR
7 = RH FRONT 9 = RH REAR
0 = FOR SINGLE SUSP RR SPRING
THE SECOND AND THIRD POSITION DENOTES SPRING LOAD RATE.
SC WT
SB WT
THE SAME INFORMATION CAN BE OBTAINED UTILIZING THE R.P.O.
FICHE IN CANADA.
R.P.O. FICHE IDENTIFICATION CANADA ONLY
RPO:AM6 A01 C49 C60 D35 D4N D9C E5Z E9Z F40 GX3 JA2 J41 K05 K60
LB6 ME9 MX0 NA5 NK5 OST PB9 QMW T76 UA1 UM7 UQ1 U19 U64 U73 VK3
V73 X05 YT9 ZG4 Z31 Z49 6RZ 7RZ 71U 79D 79I 799 8BJ 9BJ
2. ONCE THE CODE HAS BEEN DETERMINED, SELECT THE APPROPRIATE
SERVICE REPLACEMENT FROM THE CHART.
3. IN CASES WHERE THE SPRING TAGS ARE NOT AVAILABLE AND
THE CODES ARE NOT ON THE S.P.I. LABEL OR THE R.P.O. FICHE,
THE DEALER CAN SELECT THE CHART TO BE USED DETERMINED BY
THE MODEL, ENGINE AND SUSPENSION OPTION OF THE PARTICULAR
VEHICLE. ANY SPRING IN THE RANGE MAY BE SELECTED, BUT A
GENERAL "RULE OF THUMB" IS TO CHOOSE A SPRING IN THE
MIDDLE RANGE.
A HIGHER OR LOWER LOAD SPRING MAY ALSO BE SELECTED BY
MOVING UP OR DOWN THE CHART FROM THAT POINT.
4. WHEN THERE IS A DIFFERENCE BETWEEN PARTS USED IN THE U.S.
AND THOSE USED IN CANADA, THE U.S. NUMBER WILL BE FOLLOWED
BY THE LETTER "U" AND THE CANADIAN NUMBER BY A "C".
TO UTILIZE THE SPRING CHARTS, THE FOLLOWING STEPS SHOULD BE
USED:
1. OBTAIN THE SPRING CODES FROM TAGS ON ORIGINAL SPRING
OR FROM THE "SERVICE IDENTIFICATION LABEL" LOCATED ON
THE VEHICLE (SEE INFORMATION IN FRONT OF CATALOG FOR
EXACT LOCATION OF "SERVICE IDENTIFICATION LABEL"). THE
S.P.I. LABEL EXAMPLE SHOWN BELOW HAS THE FOLLOWING SPRING
CODES 65C,7SB,8WT,9WT.
S.P.I. LABEL U.S. AND CANADA
1 G 1 B N 6 9 H X E 5 1 0 0 0 0 1
C90 C95 DF3 D3C D33 D08 E5Z E7D FFL F40 GG1 GW9 G60 GU2 G89
JA1 JA4 K05 K22 K99 LV2 WW9 WX0 NA5 N81 NK1 NK3 N33 N67 GLW
T87 UJ3 U23 U35 V08 V10 WC3 WG2 YT9 Y56 01L 6SC 42B 42I 42Q
42T 409 7SB 8WT 9WT 11A 90A
NOTE: THE FIRST DIGIT DENOTES SPRING LOCATION, I.E.
6 = LH FRONT 8 = LH REAR
7 = RH FRONT 9 = RH REAR
0 = FOR SINGLE SUSP RR SPRING
THE SECOND AND THIRD POSITION DENOTES SPRING LOAD RATE.
SC WT
SB WT
THE SAME INFORMATION CAN BE OBTAINED UTILIZING THE R.P.O.
FICHE IN CANADA.
R.P.O. FICHE IDENTIFICATION CANADA ONLY
RPO:AM6 A01 C49 C60 D35 D4N D9C E5Z E9Z F40 GX3 JA2 J41 K05 K60
LB6 ME9 MX0 NA5 NK5 OST PB9 QMW T76 UA1 UM7 UQ1 U19 U64 U73 VK3
V73 X05 YT9 ZG4 Z31 Z49 6RZ 7RZ 71U 79D 79I 799 8BJ 9BJ
2. ONCE THE CODE HAS BEEN DETERMINED, SELECT THE APPROPRIATE
SERVICE REPLACEMENT FROM THE CHART.
3. IN CASES WHERE THE SPRING TAGS ARE NOT AVAILABLE AND
THE CODES ARE NOT ON THE S.P.I. LABEL OR THE R.P.O. FICHE,
THE DEALER CAN SELECT THE CHART TO BE USED DETERMINED BY
THE MODEL, ENGINE AND SUSPENSION OPTION OF THE PARTICULAR
VEHICLE. ANY SPRING IN THE RANGE MAY BE SELECTED, BUT A
GENERAL "RULE OF THUMB" IS TO CHOOSE A SPRING IN THE
MIDDLE RANGE.
A HIGHER OR LOWER LOAD SPRING MAY ALSO BE SELECTED BY
MOVING UP OR DOWN THE CHART FROM THAT POINT.
4. WHEN THERE IS A DIFFERENCE BETWEEN PARTS USED IN THE U.S.
AND THOSE USED IN CANADA, THE U.S. NUMBER WILL BE FOLLOWED
BY THE LETTER "U" AND THE CANADIAN NUMBER BY A "C".
It also tells us that there isn't enough difference between a BZX and a BZW to really be noticed. Notice it says if in doubt shoot for something in the middle. If there was really a 1" height difference to be found between springs, obviously this shoot from the hip policy could cause problems.
Then as we continue to look at the charts, the spring codes are listed under headings that explain which cars came with which springs. Notice that the codes that determine which springs should be used deal with
-suspension level, i.e. WS6, FE2, F41, Y99, Z28, etc.
-engine, i.e. LH0, LB9, L98, LG4, LU5, etc.
-tires, i.e. QYC, QLC, QAC, etc.
Next, what we see is the spring codes and part numbers rated from highest load rate, down to lowest load rate. What this tells us is that ANY of a handful of springs can be considered correct for certain combinations. For example, A 1992 WS6 Firebird could have BZY, BZX, BZW, CDB, or BXY front springs from the factory. We see this almost identical selection of springs as being available on a 1984 Z28, or a 1984 WS6 Firebird. This shows us that the late model "special springs" as would be found on a 1LE, or WS6 Firebird, or G92 Z28, or IROCZ, are the same as a basic 1984 L69 Z28 or Trans Am WS6.
To drive the final spike into the heart of the "special spring" myth, note that the service numbers for replacing several springs are the same part number. Obviously if there was such a great difference between one spring and another, the replacements would be much more specific then one size fits all.
So what does this mean? It means if you have a V8 with an FE2 suspension, you probably don't have much to gain by swapping to "Iroc springs" or "1LE springs" or "WS6 springs". It means that the springs codes don't really tell you much about a car.
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