83 Z28 Suspension vs 87 IROC-Z
 

I own an 83 Z28, and after some research, I've found that in this particular year, the suspension was the stiffest of the 3rd gens. In following years, they backed off until the arrival of the 87 IROC... I have 34mm solid sway bars, but no wonderbar like in the IROCs. With my engineering knowledge, the 34mm solid is MUCH stiffer than the 36mm hollow like in the IROCs. I also dont know the specs on shocks and springs for either cars... I've driven some IROCs and they dont seem to take corners as well as my Z28. Although, there is more flex in my front frame than in the IROCs. I have an all stock suspension (with original parts and bushings). So, my question is, which car has the stiffer suspension over all, the 83 Z28 or the 87 IROC-Z? I'd like some input...

Re: 83 Z28 Suspension vs 87 IROC-Z
 

Welcome to TGO. I'd like to see that research. In answer to your question, the IROC suspension is stiffer regardless of year. The following from the Camaro White Book (just to provide a general idea of the differences in the two cars):

"...the IROC featured lower trim height and center of gravity, special front struts, springs and jounce bumpers, Delco-Bilstein rear shocks, special rear springs and stabilizer bar, higher-effort steering, increased caster, front frame rail reinforcement, Goodyear Eagle P245/50VR blackwall tires on 16/8 aluminium wheels.... The IROC was not a separate Camaro model; rather, it was an option available with Z28 models."

JamesC

Re: 83 Z28 Suspension vs 87 IROC-Z
 

The suspension is identical; but the soft wear parts, namely the springs and shocks and sway bars, were stiffer in the IROCs. The chassis was slightly different, in that the IROCs got the "wonderbar".

I don't know of any 83 cars getting a 34mm sway bar. Mine (L69 5-speed WS6) had the 32/21 combo IIRC. All of that stuff is LONG gone now though, it's been at least 10 years since it all went in the trash. I have the 34/24 ones there now.

But all of that is just stuff that either needs maintenance periodically anyway, or that just unbolts from the one car and bolts right up to the other. Not really worth worrying about, beyond minor historical value. Any 20-some-year-old springs are going to be worn out and sagging, regardless; so things like that, aren't worth swapping from one car to another. Just like you wouldn't go to the junkyard and get spark plugs out of some other car to put in yours. (well, I hope not, at least...)

I have a "wonderbar" in my 83, along with the replacement stiff Moog springs such as are listed for IROCs, and a rear end with PBR disc brakes out of a 90s car. All of that stuff is totally interchangeable.

Re: 83 Z28 Suspension vs 87 IROC-Z
 

FYI, my 85 IROC was originally equipped with a 34/24 combo. IIRC, the 36/24 combo didn't arrive on Camaros until 89 (earlier on Firebirds, etc.)

JamesC

Re: 83 Z28 Suspension vs 87 IROC-Z
 

How can the 83s have the stiffest suspensions when the stiffest springs they came with is roughly 420 in/lbs and the stiffest springs available (on the IROCs) are ~700 and the stiffest on verts are ~750?
And, from what I've read, the larger 36mm even though it is hollow, is stiffer because only the outer section of the bar is affected by the body roll of the car - not the entire thickness of the bar. Therefore, the 36 is both lighter and stiffer than the smaller 36.
Why wouldn't GM just put the 34 back onto the IROCs instead of building a whole new sway bar set-up?

Re: 83 Z28 Suspension vs 87 IROC-Z
 

GM does like to cheap-out alot... so MAYBE the 36mm hollows are alot of fancy advertisement rather than function. I still have doubts its stiffer than the 34mm solids. Like I've said, I've done stress tests on these things, and the solids always come out stiffer. Anyway, I wont argue...

So, there were no 34mm in 83??? My suspension is very stock. My rear end is even slowching. My measure ments showed 34/26... (i'm not sure about the 26, it might have been 24... bad memory)

The great thing on my car is the upgrade to fourwheel disks. Mind you, they replaced drums on a 10bolt 3.73, so the brake lines are wavey at the ends. I bought my car last year before winter, and am learning more and more things about it every few weeks...

Ok, thanks for your input folks...

Re: 83 Z28 Suspension vs 87 IROC-Z
 

i have a 36 hollow and a 34 solid bar, the 34 solid was stiffer and made the front end more responsive, i switched to the 36 because i thought it would be stiffer, it's not

Re: 83 Z28 Suspension vs 87 IROC-Z
 

Heres some info....

https://www.thirdgen.org/camaro_spring_rate

https://img.photobucket.com/albums/v...x/swaybars.jpg

https://img.photobucket.com/albums/v...ocksprings.jpg

Re: 83 Z28 Suspension vs 87 IROC-Z
 

That is very informative. owning an 83z, I cannot vouch for the car feeling stiffer than a friends 87iroc. The cars feel exactly the same in the terms of suspension.

Cheers!!!

Re: 83 Z28 Suspension vs 87 IROC-Z
 

What is the suspension on the 87 IROC is it the FE3 then?

Re: 83 Z28 Suspension vs 87 IROC-Z
 

Welcome to TGO. FE2.

JamesC

Re: 83 Z28 Suspension vs 87 IROC-Z
 

I have an 83 also, and mine has the 34/24 combo OE as well even though a lot of resource sites say it was not an option through the years. I have driven other third gens and out of all of them, I would have to say mine handles the tightest, even with saggy rear springs, original shocks, and a 100,000 rounds on the odometer.

Re: 83 Z28 Suspension vs 87 IROC-Z
 

Edit: My bad.

JamesC

Re: 83 Z28 Suspension vs 87 IROC-Z
 

I have a 1987 Camaro IROC-Z. Im doing a front end rebuild soon and i am going to get new sway bar bushings. But i dont know what size my sway bar is. Would anyone happen to know what the size is because i have no clue? thank you

Re: 83 Z28 Suspension vs 87 IROC-Z
 

Guessing, I'd say your IROC has the 34/24 combo.

JamesC

Re: 83 Z28 Suspension vs 87 IROC-Z
 

okay i only needed the front measurement for now. fast reply too,thanks

Re: 83 Z28 Suspension vs 87 IROC-Z
 

I will tell you this I've had many new Z-28's, IROC's etc. didn't have a 82 Z-28 but drove them......did have a new L69 5 speed bought outta state I know for a fact it was early build because when I took it in in early April 83 with a broke T-5....the Service mangager said I heard we were getting these. Ten broken T-5's and th balancer going thru the radiator they damned near got it back. Everytime I'd race it I'd cut or remove the altenator belt it wouldn't stay on over 5200 rpm's but with afew mods my motor would spin over 6k by the stock tach. Car and Driver said the 84 L69 5 speed was the best handling car in America over th Corvette because they softened ths sprinds so they tested it against the 944..........944 was fastest one the street Z-28 trounced on the street check it out. I bought a Z-51 Corvette they were on crack that was a handling S>O>B> the latter cars IROC and all really need stiffer springs IMHO. /the latter cars 91-92 with stiffer springs really rock....but that early production 83 L-69 vs the first 86 IROC I owned (new) ? perfer the early.......best of both worh worlds? Late car losts stiffer springs Koni Yellows......lots of or mods +big bucks. But yeah a low mileage early car like fricken rails.

Re: 83 Z28 Suspension vs 87 IROC-Z
 

I currently have two 82's one totally original and one heavily modified, I have had many others over the years, 92 Z28, 89 GTA, 84 5.0 HO, 89 IROC... There is something to be said for the earlier cars having a "tighter and lighter" feel when comparing stock to stock with the later IROC cars. In my opinion although the early cars do have a softer suspension they respond differently in a good way because they are lighter than the later cars (comparing stock to stock). My completely stock 82 (Still has the original spare tire and jack, AC, etc....) weighed in at 3300 pound with about 3/4 tank of fuel. I think this adds to a more spry feel of the cars handling and a better balance, just my .2 cents :)

Re: 83 Z28 Suspension vs 87 IROC-Z
 

My God Apache, I'm originally from Little Rock and speak perfect Arkansawan and I could barely understand anything you just typed. Were you tired when you typed that or just drunk? Was that an Indian dialect or what? Throw us a bone here, help us a little bit and get that translated for all to read.