IROC spring difference?
#1
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Car: 2003 BMW E46 M3 Vert
Engine: 3.2 I6 M power 333 h.p.
Transmission: SMG 6 speed
Axle/Gears: 3.62 posi
IROC spring difference?
My 85 IROC/Z has rear spring codes 8NN and 9NN. I have seen other IROCs with 8NL and 9NL. I thought the difference was because I didn't have T-Tops and they did. Here I find an IROC without T-Tops and it has the 8NL & 9NL spring codes. anybody know why the difference?
#3
Re: IROC spring difference?
I looked at my spring codes on my 1985 1C5 Iroc-z and they were the 9NL and 8NL. I also checked the RPO codes on two other 1985 1C5 Iroc-z that I have copies of and they were the same. My car was made in the 2nd or 3rd week of May, I then looked at the "black 1990 1LE 5.7 #25"RPO codes that are on Third Gen and noticed that they were like yours the 8NN and 9NN. Maybe, late 1985 through 1990 had the 8NN and 9NN. I don't have any other RPO codes to look at. If that's not the case yours has the same as the 1990 1LE.
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Car: 1992 Camaro RS, 1999 GMC Jimmy
Engine: 305 TBI, 4.2L I6
Transmission: 700R4, 4L60-E
Axle/Gears: 10 Bolt 2.73, 10 Bolt Posi 3.42
Re: IROC spring difference?
If it helps, i have a 92 RS with a 305 that has 9NL and 8NL.
#5
Re: IROC spring difference?
Your RPO code information on your 92 RS springs tells us there wasn't a change of springs in late 1985 to 1992. If that's the case, mr396's 1985 Iroc-Z has springs with the same 8NN and 9NN code as the 1990 #25 1LE. It looks like we should check to see if all 1LE Camaros have that code and if anyone else has them on their Camaros. They might be a stronger rated spring?
#6
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Re: IROC spring difference?
The springs were computer selected based on the weight of the options. I did not compare all of the options on these labels but I'd bet that there are total vehicle weight differences that required different spring rates. I would also bet that the minimal differences in the spring rates are why there are only one rating for aftermarket replacements.
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Car: 2003 BMW E46 M3 Vert
Engine: 3.2 I6 M power 333 h.p.
Transmission: SMG 6 speed
Axle/Gears: 3.62 posi
Re: IROC spring difference?
The springs were computer selected based on the weight of the options. I did not compare all of the options on these labels but I'd bet that there are total vehicle weight differences that required different spring rates. I would also bet that the minimal differences in the spring rates are why there are only one rating for aftermarket replacements.
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#8
Re: IROC spring difference?
#11
Re: IROC spring difference?
I just looked at the RPO codes in a 1989 Iroc-Z with the G92 performance axle and it had the same springs that you have on yours. They only put that in 1426 cars in 1989. They apparently put those springs in if you ordered the G92 performance axle.
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Car: 2003 BMW E46 M3 Vert
Engine: 3.2 I6 M power 333 h.p.
Transmission: SMG 6 speed
Axle/Gears: 3.62 posi
Re: IROC spring difference?
Here is a cool thread on the subject. https://www.thirdgen.org/forums/hist...ur-spring.html
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