qwank

I want to install a rear sway bar on my '81. it has the standard suspension, but it does have a 1 1/8" front bar.

I see lots of stock sway bar setups on Ebay for sale. I'm guessing I want the 7/16" bar, because I believe the 9/16" is for the big block cars?

Is this correct?

would the 9/16" bar work better with the 1 1/8" front bar?

MelWff

With a front bar that large you probably could go even larger than 9/16". I believe Addco makes a 5/8" bar. I think the 7/16" is too small.

SOMFormula

I have a VB&P bar I'm going to throw up for sale, here soon.

It's a 5/8"...I believe. I can throw up some pics.
It's the entire kit. so it has all the brackets needed and the bolts for a direct bolt-in.

I took it off cause I'm going to a stiffer spring, so I don't need it anymore.

Shark Racer

Most people report that a large sway make these cars pretty loose...

qwank

well from what i'm seeing online, the FE7 suspension in later cars had 1 1/8'' front, 7/16'' rear. i'm guessing GM used that combo for a reason

jb78L-82

1 1/8 front bar with 3/4 inch OEM style rear bar -Neutral! Totally depends what suspension, tires, and driver of the C3. A 50:50 weight distribution makes these cars very good road cars. They Do NOT inherently oversteer even with rear bars!

qwank

Thanks, but I want the stock style bar and links

SOMFormula

No problem. Just figured it would be cheaper than buying new.

To JB78L...
My car was VERY loose in the rear! That's why I removed mine and I'm going to a stiffer spring and no sway bar.
BTW, I only did one auto-x with the rear bar. I removed it and the next day I was a lot faster and smoother. The car transitioned a lot easier and I was able to cut the apex of the corners much tighter and even accelerate harder (with way more confidence) out of turns withOUT the rear sway bar.
Just my experience with it.

qwank

I'm leaning towards the 7/16" bar right now, unless someone convinces me otherwise. I'm not racing, and I have the stock fiberglass rear spring.

roadblock69

Use caution when making changes to your suspension. GM generally set the cars up for slight understeer. If you want to retain fairly neutral handling it is best to stay with a tried and proven setup. Adding a rear sway bar and doing nothing else to the suspension could be a recipe for watching your rear end pass you on a corner.

TheSkunkWorks

Don't install any particular bar based solely on what may or may not have worked for anyone else before properly diagnosing your own car's current balance characteristics. And, as I'm sure I've cited a million times by now, don't assume that how your car drives at 7 or 8/10ths of its actual limits is an accurate indication of how it will behave at 10/10ths. Ultimately, any decision to add or increase rear bar which is not based on the latter is a bad one. Besides, you can absolutely sort your handling without one. Oh, and there's nothing wrong with mild understeer on any street machine. My $.02


TSW

gcusmano74

IMHO, mild bars are best for the street. Racing/autocrossing is a whole different thing.
Also IMHO, a 7/16 bar is so soft it doesn't do anything useful. (You can bend it by hand!)
Try to find a 9/16 rear bar from a big block car, if you can. Balance it with a 15/16" or 1" bar on the front.

Jason Staley

I'm running a 1" front and a factory 9/16" bar in the rear. I find the car to oversteer a bit right now when I'm at the limit.

I'm thinking about trying a 1 1/8" front bar later this year and see if it improves things are not. Car isn't too bad now, but this is one option I'm thinking of trying. First I need to increase the spring rate, then shocks, then I'll try the sway bar. Going to try one thing at a time at the track and see how things go.

vettehardt

On my 76 I am running a 1 1/8" on front and 3/4" on rear. This is with a 360# fiberglass spring in the rear and 500# springs in the front. It has KYB gas a just shocks all the way around. The car is mostly neutral but can get the rear to come around on me under some circumstances.

On my 73, i am running pretty much the same setup except a 420# spring in the rear. This car will understeer long before it will oversteer, but the car is still very quick in the autocrosses.

Overall, I believe my 73 is faster on an autocross course, but the 76 handles a very tiny bit better. On a road course, the 73 is better. The 76 does tend to oversteer through long sweepers like turn 8 at Putnam park. I tried unhooking the rear bar and it made it even worse.

Sayfoo

This is what I found to be true.
I bought front and rear bars as recommended by a major Corvette suspension parts co. and it did not work for me. Big time oversteer. So I removed the rear bar and got a pretty good understeer. I ended up with a big, 1/18" I think, front and the origional BB 7/16" rear and I now have a pretty neutral car.
The best that I could figure out, is to install a big bar up front, then experiment with the rear to get what you want. Seemed to work for me.

jb78L-82

I think some very good advice here! My comments are mostly based on what has worked for me with my setup but may not be work for someone else unless that car has a setup very similar to mine

Some general comments about using a rear sway bar:

1. If you have a SB engine like the later C3's, the factory gymkhana suspended cars that used a rear 7/16 inch rear bar on a 78 C3 had a front bar of 1 1/8 inch bar. The 79-82's used the same front bar with the sport suspension. I use 550 front springs and Bilstein HD shocks with my setup- a rear 3/4 inch OEM type bar.

2. I don't know this for sure, but my guess is the rear sway bar equipped cars generally had a front bar of at least 1 inch to balance the package. I would not use a rear bar on cars with front bars smaller than 1 inch.

3. I would not use an aftermarket rear bar with endlinks like the front bar on a C3 since these bars restrict movement of the IRS.

4. As others have noted, if adding a rear bar makes the car oversteer, one option is to increase the diameter of the front bar to dial in more understeer. I also run poly bushings on my front 1 1/8 inch OEM bar both mounting and endlink bushings which effectively makes the bar "bigger".

5. Getting the rear planted is key. I run a 360 composite with the 3/4 inch oem type rear bar with Bilstein Sports (30% stiffer than the front HD's) with Competition Adjustable heim jointed strut rods which help greatly in eliminating unwanted camber changes-no rubber bushings.

6. Tires! Again running stock type 15 inch 255/60/15 tires with VERY cushy sidewalls contributes greatly to unwanted rear movement. I run 255/45/17 ZR ultra high performance modern rubber with minimal side wall flex.

Hope this helps!

qwank

good advice

Easy Mike

You are correct.

redvetracr

who sells a factory style 3/4 rear bar?

jb78L-82

No one that I know of today. Bought mine from MidAmerica 10 years ago for $100. No longer available from them but not sure about the general corvette parts market.