WE all know that the Z28 went away in '88 and the IROC-Z became its own model. I also believe that beggining in '88 the standard rims for a base IROC-Z were the 15" Z28 rims from previous years. My question is did anything else change as far as suspension on the base Iroc-z? For instance if you got the base 15" wheels did you get the same steering box that the 16" rimmed cars got with the stops to accomadate the larger Tires? I know in the fourth gen cars the SS had different suspension levels after the introduction year, I was just wondering if this was the case with Iroc-Z's in 88-90, if indeed the base cars got somewhat less of a suspension than the cars with the upgraded 16" Rims. I really hate that GM did this, Irocs should never have got 15" rims, after all the whole premise of the IROC-Z was that it was the ultimate handling Z available and should not have been watered down.

 

i'd like to know this also!

 

Well all the 15" IROC's I have come across have had the same "Z" steering box that the 16" ones came with. I swapped the 15" IROC rims for the 16"s on my old 89 IROC vert and there was no problem with the steering stops whatsoever.

 

According to all the research that I have done (as I have an 88 Iroc with the 15" option), you did not get the quick ratio steering box unless you had the 16" rims. I have checked the #'s of my car and 2 other 88's with 15" wheels, and all have the same standard steering box. (Although mine drives fine with 16" Iroc wheels)

 

15" rimmed cars did get the wonderbar though didn't they?

 

What do you mean by "checked the #'s"?

 

The only #'s I could find on the steering box.

 

Did it have a "Z" cast into the top of it?

 

None did, no.

 

Yeah because that is the 16" IROC steering box. That's funny because the 15" IROC's I have come across (one being mine) have had the "Z" steering box. Maybe some guys on this board with 15" IROC-Z's could chime in with what they might have.

 

Hmm, now I am interested! I was told that without 16's, no quick ratio... I might not have to buy one!

 

yep mine('89) had 15" wheels,but they're not the same as the z/28 wheels,they are the 2 line IROC version,now my car does have the wonderbar,but also has drum rear brakes,when did they put TPI,instead of TBI on camaros other than IROC?here's a little comparison on the 15" compared to 16"

 

89 was the first year of the 15" IROC look alike wheels.

Are you asking when they installed TPI engines in RS/Z28/SC lines? In 85-87 the Z28 could have the 305 TPI engine and the 91-92 RS B4C's had TPI engines standard. Other than that, it was only IROC's with TPI engines. Supposedly the 1990 RS convertible had the 305 TPI engine as an option, but with zero produced I tend to disbelieve that one year option.

 

The "Z" cast into the top of the steering box has absolutely nothing to do with ratio. Both my RS and IROC have the "Z" in the box, but the IROC has quick ratio whereas the RS does not. I have seen several non-QR boxes that have the "Z" cast into the box. Just my $.02...

 

That could possibly be why my 89 IROC orginally 15" wheels steering doesn't even compare with my 87 GTA. The GTA's steering feels kind of stiff but the IROC's is very loose, like easy to turn, not loose parts. The IROC does have the Z cast into the steering box also. Hmmmm.