A couple of people have asked about spring rates available to tune the suspension to various levels of comfort or harshness. For example, the IROC is legendary for bone-jarring rides over any road irregularity, while the RS models have a softer, more spongy ride. Having both an '87 IROC and '92 Z28in our garage, I've come to the conclusion that GM produced the '91-'92 Z28 model years with slightly softer front springs in response to customer complaints about harsh suspension. Driving the '92 shows it has a hard ride, but not to the "take no prisoners" level of the IROC, and still provides very good handling characteristics -- without the soft wallowing of the RS's 424.0 lb/in spring rate. I believe the '91-'92 Z28 spring rate is 707.0 lb/in, slightly less than the IROC 748 lb/in.

Hopefully, I'll have time later this year to MOD my IROC with 1LE front brakes and a set of '91 Z28 springs from a donor car. In the meantime, the compiled data from other sources on spring rates for our cars is in the attached PDF image.

 

Ed:
I have a Moog catalog if you want to look it over. Also, you have the option of G-body springs and S-10 springs for different rates. Just in case you dont like the 3rd Gen. listings.

 

Great lookup Duck! Since it's tax time I've got about 2500 to spend on car parts.What do you think would be better for a 1nch drop?Moog iroc springs or eibach prokit?

 

I hear good results from the eibach's, but personally, with our conversation about how hard it is to drive around up there, I'd be afraid to drop the car any amount. I bottomed out enough. Haven't bottomed out down here in Tucson yet, which is nice. But the tradeoff is that most of the roads are unmaintained, so I*really* feel the bone-jarring IROC suspension. It makes me happy on the highway though.

 

Dude, that's the thing about Tucson I will miss the least! I totally feel you on the IROC ride in the streets of Tucson. Kingman feels smooth compared to it (well, except Butler!)

Duck, your posts are a wealth of information!!!!

 

tom,
Are you implying that S-10 and G-body springs can be used on a third gen as well?

 

Yes you can. I know lots of guys run the IROC front spring on G-bodys to stiffen the front end up. Just another option for a softer riding spring with the other listings.

 

Tom, if you have the tech details on the G-body springs, I'll add them to the PDF article.

 

I'll have to dig it out for you.

 

Excuse my ignorance but why would G-body springs tend to be softer? I have a set of G-body Bell Techs I would love to try on my 3rd Gen.

 

Most G body cars were boats. Never considered a "sports" car. Even the "stiff" F41 suspension package was only in the 500lb per inch rating. Still softer then the standard "RS" spring package.

 

Ed,
You are more than welcome to come over and view my Pontiac catalogs for springs if you want.
You know how busy I am, with the full time job of doing.....................
Nothing! Ha!

George