Just curious about what GM were thinking.

IROCs got the wonderbar and the bilsteins where the GTAs/ HP Firebirds in general instead got the thicker sway bars and some say the GTA spring rates were slightly softer than the IROCs.

Okay, I can somewhat understand the IROC to be the more performance orientated car and the GTA the more 'refined' car adn the thicker sway bar/ lower spring rate maybe achieves a softer around town ride but still retains some decent road holding.

So how about the Formula. This was the no-fat high performance pontiac. But it retained the thicker sway bar and didn't get the wonderbar or the bilsteins. Maybe the front 36mm sway bar on the firebirds was due to the heavier front end (pop up lights)...

Did Chevrolet get a hold of the wonderbars and an exclusive contract with bilstein? I know these cars were built to a budget so perhaps GM didn't think the firebirds would be driven as hard? But then the Formula creeps back in as the racer firebird

Just curious about learned thoughts on this

I have a 1988 IROC and never realised the Bilsteins were factory?

It really depended on the Engineers and what they wanted in the car. Consider that the Firebird was considered a step up from the Camaro, so ultimately it was designed to be a little nicer, typically with more options on the base levels, designed to be slightly quieter from road noise, albeit maybe not noticeable to most human ears 20 years after production ended.

With that said, the Camaro got the Wonderbar and Oil Filled shocks & Stuts, the Firebird got Gas filled shocks and struts which gave a superior ride, and with the larger sway bars with no loss in handling, and an improved ride. If I remember correctly when a magazine compared the cars there was no significant advantage of lateral performance from one model to the other.

Ultimately the Camaro got 36mm front and 24 rear sway bars in 91 & 92, and I think the wonderbar went away.

Honestly I suspect that the Oil Filled shocks & Stuts being harder riding may have determined that they needed to reinforce the front subframe area where it is prone to cracking. The Wonderbar has been noted that it could indeed help reinforce the area by the steering box in-particular.

The Formula was really designed to be a GTO of the day. It was a no frills performance car, Since it had no ground effects, some other things were done to reduce weight such as less sound insulation it was the lightest of the performance Firebirds which would give it the best performance of the group. Whether or not it was better than the IROC, I would think that an equal Formula would give an IROC a run for its money, I also recall an article calling the Formula the most fun to drive when comparing the GTA, Formula and IROC.

John

From the tests I've read over the years, Chevrolet wanted the Camaro to be the higher performing car and used the best things they could to achieve that, while Pontiac wanted a more refined car. Chevy kept it simple and direct while Pontiac had more interior options, supposedly less road noise, and a less harsh ride. Camaros got the better air intake for a little more power, a suspension that put up slightly better numbers, and American street bruiser looks while Pontiac wanted a more "European" look and ride. It was noted though, that even the Formulas were heavier than IROC-Zs since they had those flip up lights, big spoilers, and possibly more insulation. The fiberglass Camaro GFX and spoiler are actually light. The Formulas were noted to feel lighter because of the more compliant suspension, the GTAs just felt all-out heavy, and the IROCs felt the sharpest and the most racy. I've had experiences in IROCs and Formulas and I agree with that. Both are very good handling cars with slightly different characteristics. The Camaros seem to have better turn-in with a harsher ride while the Firebirds feel a little less responsive but more forgiving. I'd take the IROC-Z though.

GM's emphasis during that period was to give the IROC-Z sharper handling at the expense of ride and the opposite for the GTA.

For what it's worth, I am almost positive that the IROC-Z's Bilstein shocks and and Delco struts were gas filled and not oil fill. Someone correct me if I'm wrong.....

You're right Charlie, I didn't catch that. They are gas. As for the wonderbar, that was an IROC-Z exclusive to enhance the frame for better rigidity and feel.

interesting thoughts- thanks everyone for your input.

its a logical argument about the stiffer suspension requiring more chassis reinforcement and the images that GM were trying to portray for the two cars.

Yes, everything is relative; perhaps especially in regard to GTA refinement!

So did IROC's get Bilstein front struts? Or did they only get Bilstein rear shocks? I've read conflicting things on this. Im also fairly certain 91-92 Z28s got the Wonderbar also - I have a wonderbar that allegedly came out of a 92 Z.

And Im not so sure all of these things you guys attribute to "GM" are necessarily GM's decision, so much as it is the individual divisions coming up with their own way to do things, albeit with GM's implicit approval.

FWIW, according the the Camaro White Book, "...special front struts...Delco-Bilstein rear shocks...

JamesC

IROCs only had Bilsteins on the back, for sure. As for the rest of it, I will say I prefer the WS6 feeling to the IROC suspension. My WS6 TA is more comfortable than I would expect...barely harsher than my base-suspended TA. The more I own my WS6 TA, the more I almost wish I'd held out for a low-mileage LB9 5 speed Formula. It would've been cool to have the "ultimate" mainstream Firebird performance model.

I may still end up buying one...you never know with me After buying these 3 in the past 2 years, and getting to better understand the nuances that made various engine/suspension/trim combos unique, I think my next one would have to be a 5 speed Formula hardtop. As much as I've always wanted a GTA, and love my TAs, I'd love to experience the more elemental nature of a Formula. Unlike my 3 I have now, my '89 LB9/A4 formula I had back in 2002 was a 100k mile, neglected rat....hardly the kind of car that would have given me a real feel for what those cars were like.

me: Hello everyone.

.ORG: Hi Tony.

me: Formulas rule, that is all.

I am honestly not sure about what your question is. Insofar as time has caused GM to evolve, at one time GM was run by its individual brands, IE Chevrolet, Pontiac, Buick, Olds, Cadillac, GMC etc.. They all were basically their own company each would make their own decisions on what they would make. As time went on, more and more pieces and parts became universal, things like Door handles, strikers, door lock assemblies, hinges, bolts, etc...

Matter of fact, as a little tidbit of interest, because Pontiac and Chevrolet would order parts and pieces separate, during the 70's and possibly the early 80's the same exact bolt was less expensive for Chevrolet to purchase than Pontiac. Both had their own Buyers therefore they worked out different prices with suppliers. This has changed more recently to where all bolts are purchased under one order, not two.

As for design, again, GM and Pontiac would have their own design teams, and I suspect the divisions still do to some extent. These teams would then collaborate together on designs to come up with one design. Later on, especially in the 80's those deign teams went away and corporate designers had taken over, therefore you had a Chevrolet Cavalier, Pontiac Sunbird, Cadillac Cimeron, Olds Omega, all which were in essence the identical car, with different stickers, and grills. The Chevrolet Cav and Cadillac Cimeron actually used the exact same fenders, and they were apparently interchangeable, but as a bump shop, the Cadillac part was more expensive.

Now as it stands there are apparently some things that is under corporate, and others under the brands. An example was given by an interior designer, I do not remember the specifics, but if a Chevy got 2 Mil of insulation the Pontiac got 4, Olds 6, Buick 8 and Cadillac 12. So there are some differences out there.

It used to be that the divisions ran the show, they competed against each other to some extent. That was when GM was on the top of the heap, had about 50% of the market. The GM banner was to keep costs down, now Corporate runs the show, and they are floundering... History has shown that competition, even internal, is the best way to run a business...