I would like my 91 RS TBI 305 daily driver to handle like my 90 IROC. Both cars have stock suspension except the ROC has LCA's and a Torque arm bushing. What are the differences in the suspension?

 

Springs, swaybar, and wonder bar... not sure that there's much else. Maybe slightly better shocks/struts.

 

The aftermarket LCAs in the Iroc are making a good difference too. You'll need to get LCAs for the RS. They help with weight distribution and cornering. The bushing for the torque arm - not helping quite as much, but also a small benefit.

 

My biggest handling improvement was replacing my shocks and struts. My 1986 Firebird had a strut so completely discharged that there was no resistance when I moved the piston up and down. I went with Gabriel VST struts after comparing KYB and Monroe, because the price and ride was right, and they have a Lifetime Warranty.

The only thing is the aftermarket parts are the same, whether it's a trans-am or a v6 base model. Again, I can't tell you how happy I am with the handling improvement. Even if you don't think they are bad, if they're the originals, they are shot. Also, are the wheels the same between the RS and the IROC? Tires are also a big factor in the handling of a car too. Cheap, big sidewalls on 15's are going to be way different than more expensive small sidewalls on a 16 inch rim.

 

Wheels are 15x7 on the RS, the old Z28 ones. My IROC has the stock 16x8's. Are the steering boxes the same? My RS has the F41 suspension.

 

Springs
Swaybars
Front Lower Control Arms
Rear Lower Control Arms
Panhard
Wonder Bar

Brakes might be different too.

 

forgot, steering box is different too.

 

What's different about the front lower control arms?

 

I was thinking the same thing. The rears are different with the upgrade he has on his IROC, but stock to stock they should be the same.

 

Front lower control arms have a different "stopper" for when you turn.

Basically, if you have 16" tire combo, it stops you earlier so your tires dont rub the fenderwell.

Rears, I just won some Z28 ones off ebay, so I'm fixing to find out the difference.

 

What about sway bars? Hollow, solid, size?

 

Swaybar size is different, and also depends on which suspension package the car came with.

Search around on here about swaybars, their is listing of what cars came with what size, etc. Very helpful, also gives GM's part numbers too.

 

Thanks thats what I wanted to know!!

 

What is the difference between RS and Z28 rear LCA's?
I was looking at a set of aftermarket rear LCA's for $79 currently on eBay that look like quality
pieces.

 

Havent recived them yet matt. I am still waiting myself.

Aftermarkets for 80 bux, you better keep quiet where they are

 

do you have any proof of a diffrence.

the steering stop on our cars is on the SPINDLE, not the a-arm. you are also not taking into account the diffrent steering boxes used either. the a-arms and rear LCA's should be the same.

 

1991 Camaro. www.gmpartsdirect.com

Front Control Arms:

Left,Heavy Duty Suspension 12505473
Left,Standard Duty Suspension 14083561
Right,Heavy Duty Suspension 12505472
Right,Standard Duty Suspension 14083562


Rear Control Arms:

A. Heavy Duty Suspension,w/Performance Package,Lower 10081636
B. Heavy Duty Suspension,w/o Performance Package,Lower 10164151
C. Standard Duty Suspension,Lower 10081635

Torque Arm:

V6 10030418
V8 10034255

Track Arm:

IROC-Z 10262147
RS 10019451

There is my proof!

Only thing I'm going by "say-so" is the stopper. And yes, the spindle has an arm that hangs down, but what does it hit when you turn? A TAB on the control arm. Go look for yourself. Its on the back side. The stopping process is a combonation of BOTH spindle and control arm. Remove that tab off the a-arm, you will grind the inside of the rim on the a-arm.

 

the tab it hits, is just a flat spot on the arm, i know you are speaking of.

part #'s ok, but i have seen MANY suspension parts from many 3rdgens. of course the 1le cars got better bushings in the arms, and some freakish years got arms with holes drilled in them and spacer bracings with bolts. but we have seen it many times on this site before, some RS's have the ones with bolts. some IROCs and Z28's don't. some have the arms with the holes drilled, and no spacers, ect. especialy considering the RS we are comparing with the IROC has the F41 suspension package. i doubt there is ANY diffrence, heck the F41 equiped car, probably even has the quick ratio steering box.

 

I've have only dealt with my car and part numbers. I wouldn't be surprised if the product line ran out of one part, and put the other part in its place to keep the line running.

I had not heard of the better bushings. But after 10+years, whats it mater? They are bad.

I will inspect closely the rear lcas I get with the ones I take of my car. Hopefully I can tell a difference. I may try to email the guy and ask what suspension package the car had/has.

 

on a 91 rs, it should have the 16"x8" wheels, at least that is what mine has.

 

16's were an option. 15's were the default.

 

15's here

 

Spindles are the same (as for steering stop). The difference on the A-arms is only the steering stop tab. The performance cars came with wider 16x8 rims that would make contact with the inner fenderwell if the stop tab was the 15x7 version. Yes you get a better turning radius with 15" rims version

Dean

 

16's here and the turning radius is horrible. Also, F41 RPO and Camaro does not feel like it has
the quick ratio steering box, but I could be wrong.
Matt

 

Iroc springs are 15mm shorter than the z 28 springs were , also Irocs got special delco shocks up from and Bilstein shocks out back.

 

While installing front sway bar end links yesterday I pulled the part number tag off the front coil springs which is 14029392.
Just wondering if there is a difference in spring height on an RS F41 RPO versus Irocs and Z28's.

 

zedder. Is that while in the car, or out of the car?


Matt, that is a part number not on the usual "spring chart" you find on here. Wonder where it plays into the chart at.

 

Dale,
Hmm, makes me wonder. I'll check the part # again and pull the tag from the other front coil spring.
I know for a fact it is the original GM tag.
The build date is December ie late in the year, so who knows!
The car is bone stock and I am the second owner. I bought it 4 years ago w/ 26,xxx original miles from a couple in their mid-50's, so I doubt the springs were changed due to the mileage and they were not the "hot-rodder" type.
Unless, it was wrecked and rebuilt, however, I asked that question before I bought the car.
Later
Matt

 

I'm not doubting the part number. Mine coded like NNM or whatever, are not on the chart either. So the chart on here is missing a few #'s.

Good job on finding such a low milage car!

 

Default huh??

Damn the computer age!