Were the 91 - 92 Z28s (post IROC sponsorship) essentially the same as the 90 and older IROCs including the lowered suspension?

 

mechanically speaking, it is essentially the same car.

personally, i prefer the looks of the IROC vs. 91-92 Z28 in every possible way.

 

I agree but to be honest I like the IROC sticker but also like the ground effect package on the 91-92.

 

There was a slight difference in suspension tunings depending on how the car was ordered, however. All IROCs got the best suspension setup and 245/50/16 Gatorbacks. The standard tire on a Z28 was a much less aggressive 235/55/16 Eagle GA. I believe the spring rates were a little softer for the 235 equipped cars. I remember reading a period Motor Trend article saying that if you wanted a Z28 that handled like an IROC, "make sure the dealer checks the right boxes when he orders it."

 

I looked for a triple black 90 iroc or a 92 z28 convertible for many years and finally found a 92 25th car. I have had an iroc since 1991 and love the sticker but I also like the 91-92 ground effects. But they are 99% the same car. I like the 90-92 gauges better for sure.

 

The 91/92 Z28's with the 235/50/16 Goodyear Eagle GA tires did get softer suspension tuning. These tires came standard on the 91/92 Z28 convertibles. The 245/50/16 Goodyear Gatorback tires were an option though. Cars that came equipped with the G92 option included the larger tires.

The 91/92 RS's cars with 305 TBI motors did get 235/50/16 Goodyear Eagle GA tires as an option if the upgraded suspension package option was selected.

The Z28's did get bigger sway bars compared to the RS cars. But the RS cars with the upgraded suspension package got the Z28 steering box, slightly stiffer springs and stiffer shock tuning.

 

https://www.thirdgen.org/mt_july_199...the_5.0_corral

Shootout At The 5.0 Corral - Motor Trend (July 1990)

"The Camaro RS used in our test was outfitted with the optional 235/55SR16 tire package, which includes the "F41" suspension package that brings with it plenty of good stuff from the Z28's parts bin. Gas-pressurized struts, coil springs, and a 1.4-in.-diameter anti-roll bar up front combined with the Salisbury axle with torque arm, Panhard rod, coil springs, gas-charged shocks, and 0.84-in. anti-roll bar out back. The Z28's quick-responding 14.0:1-ratio power steering, with 2.1 turns lock-to-lock, is also used. In fact, the only Z28 items the F41 package does not include are stiffer front springs and front strut mounts, harder lower control arm bushings, slightly firmer shock valving, and marginally larger anti-roll bars.

The big 16x8.0-in. alloys from the Z28 are wrapped with 235/55SR16 Eagle GA tires on the RS model. Although providing a smaller tread area than the 245/50ZR16 Gatorbacks fitted to the ultimate Camaro, these "ride-biased" Goodyears (the same design as used on the Lexus LS 400 and other top-line cars) give up surprisingly little in terms of road-holding. What they improve upon tremendously is the level of road-transmitted noise/vibration/harshness that finds its way into the cockpit—an incredible tire, and proof that performance, good ride quality, and all-weather traction can coexist is one tire design."

 

i had mine orderd with the good stuff....then after driving it for a week. i sent it off the LPE.

even better when it came back..22 years later.still love the car..

 

My 2 cents since I own both...When I bought my 91 it had the original wheels with the original size tires. Direct comparison to my 87 IROC from the drivers seat the 91 didn't corner near as good as the IROC(87). The IROC is a t-top, the 91 is a hard top. But...After I put my 17 Inch SS wheels on the 91, TOTALLY different car! Stock suspension and the thing sticks to the road like glue! Pretty sure the IROC would now get Smoked! Maybe this summer I'll try the SS wheels on the IROC to see if it makes the same difference

 

I don't mean to stir-up any controversy, but not all IROCs got 16" wheels.

To fill the void between the IROC and the RS, left by the discontinuation of the Z28 after 1987, an "entry-level" IROC was offered from 1988-1990, and the standard equipment wheel/tire package for all IROCs during that period was 15"(that's not a typo: fifteen inches). The 16" package was optional.

The 15" wheel was exactly like the 1988-1990 double-line "2nd generation" or "later-style" IROC wheel. Here's a set I found in a SoCal junkyard recently:
https://www.thirdgen.org/forums/sout...eels-late.html
Yes, those are, in fact, 15" wheels.

So it would seem that the 91-92 Z28 was somewhat of a compromise between an IROC and 82-87 Z28s, but leaned more toward the higher-performance IROC.

 

yeah, i was going to mention about that too about the irocs...i've seen them in 15" wheels and they're somewhat different by design as well...
i prefer the styling of the 85-87 wheels over the 88-90 years...

 

I drove 8 350 irocs in 1990. They were 1988-90 and all were below forty thousand miles. The one I eventually bought and still have today is a 89 that has been converted to 1990 dash, gauges and speed density 7730 ECM. This car was hands down the best of all of them. It was 25 HP faster and handled better. It had all options including suspension, custom interior, bose radio, corvette rear brakes with aluminum calipers. It's sad that the rear brakes were 11.7 and had aluminum calipers and the front was only 10.5 with iron calipers.