Suspension Question

[qblue90]

Hi Fella's,

I was told by someone that because my car has the FX3 and the Z51 RPO's that my suspension was downgraded to the base suspension and springs. I also have RPO FE7(Heavy Duty Suspension). So my question is: Did I get the HD suspension? I can verify the suspension by the spring codes and the bar diameter. Does anyone know what the sping codes are and where I can find them for HD suspension? Also, what is the Bar diameter for HD? Thanks for your help and dont forget to wave!

 

[Hib Halverson]

MY90 spring codes
FE1
ft. FHA
rr. NYR
FE7
ft. FHB
rr. NYU

MY 90 bar diameters
FE1
ft. 26mm tubular
rr. 22mm solid
FE7
ft. 30mm solid
rr. 24mm solid

 

[qblue90]

Where can I find the spring codes at?

Thanks for the reply Hib.

Obviously, I can easily measure the dia. of the bars. If the bars are the correct dia for FE7 RPO then should I assume that the springs are correct also?

Can anyone tell me where the codes for the springs are located? Are they on the springs themselves?

Thanks,

Kev

 

[Hib Halverson]

Thanks for the reply Hib.

Obviously, I can easily measure the dia. of the bars. If the bars are the correct dia for FE7 RPO then should I assume that the springs are correct also?

Do not assume that unless you are the original owner. With a car 18 years old and having previous owners it's possible that the bars were changed.

Can anyone tell me where the codes for the springs are located? Are they on the springs themselves?

They are on bar-coded labels attached to the springs and, in some cases, they are debossed into the spring. You may need to remove the front spring to see the label.

Another thing to look for is "Z51" stamped on the front lower control arms. There were two different sets of bushings for the front lower arms. FE7 cars had bushings made of higher-durometer rubber.

As long as your car is not a Corvette Challenge car, it is unlikely it has FE7 parts unless, the springs, bars, shocks or front lower control arms were changed at some time in the past.

 

[qblue90]

Do not assume that unless you are the original owner.





Another thing to look for is "Z51" stamped on the front lower control arms.



As long as your car is not a Corvette Challenge car, it is unlikely it has FE7 parts unless, the springs, bars, shocks or front lower control arms were changed at some time in the past.

Sorry, I havent figured out how to seperate quotes yet.

I am the origial owner of the car. It was purchased brand new off a lot. I did not order it.

As for the "Z51" stamp on the lower control arms... If I find the stamp, then I assume that is good evidence that I do not have RPO FE7 correct?

I'd be willing to bet a dollar that my car is not a Challenge car. However, my center console lid lists the FE7 RPO... When the car was new, it felt stiff enough that it would knock fillings out of my teeth. I almost never used the "Perf" setting. After being stored for a few years, the car felt softer than it did before and now I have to use the "Perf" setting just to get a good feel. I think my FX3 shocks are bad(although they do not show any sign of leakage or anything) and that is causing the softer feel. Perhaps softer isnt a good descriptive term... Imagine your out on a boat on the lake....thats what it feels like now... My shocks will go back to Bilstein for a re-build this winter.

I'll be a little disappointed if I did not get the HD suspension, especailly when I can see it on my center lid.

Any idea as to the rational behind downgrading FX3/Z51 equiped cars?

I will absolutely check this stuff out when I get home from work.

Thanks for your help.

 

[qblue90]

Ok its confirmed... I have the base suspension.ad

Oh well... It's still a sweet-ass car with (probably) more suspension than I will ever need...

Still, Im bummed and dont understand the reason for the downgrade on FX3/Z51 cars. Especially when FE7 is specified on my RPO list... That could be misleading...

WTF

 

[Hib Halverson]

Ok its confirmed... I have the base suspension.ad

Oh well... It's still a sweet-ass car with (probably) more suspension than I will ever need...

Still, Im bummed and dont understand the reason for the downgrade on FX3/Z51 cars. Especially when FE7 is specified on my RPO list... That could be misleading...

WTF

It was very misleading but GM did that for two model years. There are thousands and thousands of customers who ordered the two and never knew they had base suspension.

The reason it happended was that GM didn't have the resources or the money to do the development work to calibrate selective ride for use with FE7 for either MY89 or 90. It was not until 91 that the system was paired with FE7 and, in the end, there were no differences in the shocks or the calibration.

What's worse is "upgrading" the car to FE7 is impossible because the special front lower arms used on all Z51s and Z07s were never serviced by GM. The best you can do is FE7 springs and bars but base front lower arms. Or you can put aftermarket bushings in the base arms and get that last small decrease in compliance that the Z51 front lower arms had.