1990 ZR-1 Suspension - Restoration or Upgrade to 93+?

[Erik]

Originally Posted by CamP

I use to buy into that time thing until I replaced perfectly good rubber bushings. Lot of effort and money for nothing.

Now I focus only on mileage wear. If it's old but low mileage, I leave it alone.

That's good, but we have that whole science problem. As in, rubber does age. Yes, there are things that can slow the aging, or mitigate some of the damage caused by it. But rubber parts will age and deteriorate. They just will. And a 30 year old part, installed in a car, will not be the same as it was when new.

[CamP]

Just don't be suprised when you do the work and discover no discernable difference in ride quality. If the car had a lot of miles I'd say go for it, but if it's a low mileage car you're probably just making work.

New rubber isn't necessaribly better rubber. The quality of new rubber products has gone down hill. The 50 year old trailing arm bushings in my 71 vette are still good. I also have a 45 year old schwinn unicycle with the original tire and inner tube that still holds air. I have other equipment that the rubber is junk in only a few years.

[viper107]

^^^^^^^^^^^^^^^^^^^^^^^^^^ what he said

[Erik]

Originally Posted by CamP

Just don't be suprised when you do the work and discover no discernable difference in ride quality. If the car had a lot of miles I'd say go for it, but if it's a low mileage car you're probably just making work.

New rubber isn't necessaribly better rubber. The quality of new rubber products has gone down hill. The 50 year old trailing arm bushings in my 71 vette are still good. I also have a 45 year old schwinn unicycle with the original tire and inner tube that still holds air. I have other equipment that the rubber is junk in only a few years.

That is the challenge. Knowing the quality of the modern components. Well stored, NOS parts are probably the best option, but not easy to find.

And I'll guarantee you, a 50 year old rubber part is not what it was when it left the factory.

[Vette73]

Originally Posted by Erik

Yeah, not a lot of suspension compliance in other areas to make up for that impact harshness.

Yeah not crazy about our suspension in our cars......I remember someone saying " The car rides like a Cadillac on the softest setting...... " Yeah until you hit uneven pavement.".

[ram_g]

I have no doubt that rubber deteriorates with time. But in a sample size of (2), *all* rubber and plastic components (suspension, hoses, vacuum lines, weatherstrip, misc. interior parts, etc.) in my 1991 ZR-1 with 13K miles are in way better shape than in my 2-year younger 1993 Mustang LX 5.0 with 73K miles. So while the Mustang may have received lower spec components from the get go, IMHO use conditions (mileage, storage, etc.) have as much or more to do with the condition of aging rubber components than age alone.

Currently I have no plans to change the suspension parts on my Z.

[Black Red '90]

Originally Posted by Erik

So my thoughts are first:
New stock FX3 Bilsteins or 1993 FX3?

And here's where it gets harder:
New bushings.

From what I understand, the stock bushings are no longer available. As I'm planning to keep my ZR-1 as a grand tourer, and the roads in this part of the world are not exactly smooth, I'd prefer not to add any impact harshness.

I just had to replace my front FX3 bushings. The passenger upper half was torn bad (not sure how it happened). The other side looked & felt like new. Poly was the only thing I could find. I've noticed zero difference in ride quality. They do look a little odd as they are much smaller in diameter than OE.

[32valvesftw]

As stated by several folks, you may not notice the difference...but you will have piece of mind. That said maybe drive it for awhile and see what you think. Mine is a 91 and is not very soft except on touring setting, even then it is not what I would call squishy, on sport it can be a bit harsh on bad roads. However my suspension has a lot of aftermarket parts in it, that someone else put in. I did recently replace the shocks and found that the bilstein originals were slightly different than the bilstein replacements. The difference is where the top bushings sit, on one set the tops were concave and on the other (newer) they were convex.

[Erik]

Originally Posted by 32valvesftw

As stated by several folks, you may not notice the difference...but you will have piece of mind. That said maybe drive it for awhile and see what you think. Mine is a 91 and is not very soft except on touring setting, even then it is not what I would call squishy, on sport it can be a bit harsh on bad roads. However my suspension has a lot of aftermarket parts in it, that someone else put in. I did recently replace the shocks and found that the bilstein originals were slightly different than the bilstein replacements. The difference is where the top bushings sit, on one set the tops were concave and on the other (newer) they were convex.

I'm planning some top speed type stuff for next year, so I do want the suspension to be 100%.

Hmmm. How did it effect the installation of the Bilsteins? Anything I should prepare for?

We do always have the option of going with the 1992+ springs. Would definitely give us a better ride, and I still think the 90-91 Bilsteins could certainly control them well.

[32valvesftw]

Steve at Crossed Flags did the install, I think he ended up swapping the top hats. so it fit like it was meant to.