In everyday driving and just playing around, how much of a difference would I feel if I installed a rear anti-sway bar? I have the whole rear end out of the car and this would be a good time to put one in...
It is a 1980 with a 4 speed..

 

opinions are like...(well you know) so I won`t give mine but generally when you add a rear bar you should replace your front bar with a larger one

 

Simply adding a rear sway bar will change the handling for sure, however it may not be better.

 

so perhaps I should just take it back to stock and shut up??

 

on F-41 & FE-7 cars a larger front bar and rear bar were stock...

 

Unless you're carving corners, and a bit hard, you probably wouldn't notice a whole lot of difference.

 

The 78-80 gymkhana suspended cars had a 1 1/8 inch front bar and a rear bar of 7/16 inches, and different front and rear springs from the base cars which had a 1 inch/7/8 inch (not exactly sure of the dimension but significantly smaller than the F-41 cars) front bar with no rear bar. My 78 4 speed originally had a stock gymkhana suspension and the difference between a gymkhana car and a base suspension car just in handling/steering response is VERY apparent-I have been a passenger and driven more than my fair share of 78-82 C3's with no rear bar with the base suspension and the difference is HUGH… GM put rear bars on the gymkhana cars for a reason-tighten up the handling along with the springs.

Springs F/R and sway bars F/R should be a matched set…..Will it make a difference? Absolutely, the car will feel better tied together front and rear versus the no rear bar cars which I have driven feel like the front is disconnected from the rear-on the street, not racing…my experience and 2 cent..

 

Respectfully, jb, comparing from FE7 to base versus just adding a sway bar are two entirely different conversations.

First, the FE7 sway bar is a joke - sure, better than nothing but it's about the same thickness as a brake line.

Secondly, the gymkhana cars have nearly double the spring rate than the base cars do, as well as significantly more front bar on top of having a sway bar.

I agree w/ redvetracr that if you add rear bar you're going to want to add more front bar.

My point in my previous comment is it all depends on what you're doing. If you intent to autocross or track the car, I'd definitely consider adding a rear bar along with the corresponding change to the front. I'd also be looking at spring and shock upgrades as well. If you're cruising down the road most of the time, and rarely do things that make a typical driver nervous, you're not going to notice much change.

All of that said, I rarely drive my 78 hard and I intend to dump a fairly stupid amount of cash into the suspension over the next year or two. So I'm not saying it's a BAD idea...

 

Adding a rear bar will change things, possibly a lot. Everyone's car and expectations are different. Generally, to get the car to turn flatter, you'd use a fatter front bar, then size the rear bar to tune for over/under steer. With a BB, heavier springs and fatter tires, I ended up with a 1 1/8" bar in the front and nothing in the rear. Both the original rear bar (9/16"??) and a little larger bar that came with my new front bar induced over steer. No rear bar is close to neutral steering for my car.

 

I couldn't believe the difference it made on my 77. By far the best mod for the money.

 

My 74 street driven smallblock car has had at least four complete different sets of sway bars on it over the years, from mild to "solid axle conversion kit"..
A stiffer sway bar will resist the cars tendency to roll during cornering, without affecting the ride as much as stiffer springs.
For a street driven car, a slightly larger front bar, and a mild rear bar is my personal favorite. Right now, I am running a 15/16" front bar (the factory bar was 13/16"), mounted in poly, and a 9/16" rear bar (this car left the factory without a rear bar), with completely stock rubber bushings. I am using a Hyperco EZ Ride rear spring, which is very close to the stock spring rate, but 30 odd pounds lighter. I recently installed a VB&P spreader bar kit across the front spring towers.
It's a very sweet driving car. Not ready for the track, but comfortable enough to drive for hours.
Nice.

 

Opinions as to how great adding rear bar may be aside, fact is that unless you also increase front anti-roll stiffness by an amount which maintains the current percentage split of overall anti-roll being provided by each the front and rear of the car, you will necessarily move your car's balance towards oversteer from wherever it is now. So, make sure that's what you want/need to do before simply slapping one on, and if you do it use caution while relearning your car's new behavior. Bear in mind that how a car "feels" at less than its limits may not give an accurate account of what it will do if/when you get there. Many a car that seems on rails at 7 or 8 tenths will bite you in the backside at 10/10ths, especially if you dare to lift after committing to a corner. Also, FWIW it is entirely possible to sort out a C3 chassis with no rear bar. My $.02. YMMV



TSW

 

With the advent of all of the new round-abouts, I felt that the backend of my 69 daily driver had to much roll. I installed a 5/8 bar in back. It's flatter in the corners, no effect on ride. Like 'redvetracr' states the front bar size will need to be increased. T

 

Some good comments above^ about balancing the whole suspension package-Front/Rear Springs, Sway bars, shocks, control arm bushings, rear strut rods, tires (size AND type)-All have a roll in the handling of your C3.

Let's start from the beginning using GM's C3 factory setups on the SBC/BB cars as a starting point. ALL GM cars back in the late 60's-80's, understeered at the limit-all of them-after the Ralph Nader fiasco with the Corvair (rear engined car) that would Oversteer at the limit on the street. The base SB C3's with no rear bar and soft springs, front and rear, would badly understeer/push at the limit but had a decent ride. The SB C3 (weight distribution 48%F/52% rear-1978) with the gymkhana suspension-stiffer springs F/R and bigger front sway bar (1 1/8) AND a rear sway bar (7/16) STILL would understeer at the limit-My 78 did and this fact was well documented by magazines at the time. The BB cars (weight distribution 52%F/48%Rear) with the same springs as the F-41 SBC cars had a moderate size front bar (7/8-1 inch-I think) and a 9/16 rear bar. With the front weight bias and higher roll center than the SB cars, the BB C3's would naturally understeer than a same year SB C3 (F-41) with the slightly larger rear bar (9/16)-thus the reason for the 9/16 rear bar versus the SB 7/16 rear bar.The point is that GM used a rear bar to complement the front bar which is the correct way (IMHO) to balance a chassis. I am not a fan of trying to balance the chassis with a front bar only and springs although that method is an option. I ran my 78 Gymkhana with factory bars (poly bushings) for YEARS with 255/60/15's and the car would…..understeer-even with a 360 rear mono spring which is MUCH stiffer than the factory 7 leaf steel spring-stock front GM coils. Remember almost every GM car in the 60/70's did NOT have a rear bar even though the non Y body cars SEVERELY understeered since they were all very nose heavy with some exceptions-Ralph Nader calling again…

In the 2000's, I began a major revision of the stock suspension-The only components not changed were the stock 1 1/8 inch front GM bar and the 360 mono spring. I went with 550 front springs (MUCH stiffer than the factory springs) which as a stand alone change should induce MORE understeer than the factory springs), Poly upper and lower control arm bushings (better camber control), Bilstein HD shocks (not Sports-springs are stiff enough) and a front Spreader bar (less frame flex). In the rear, competition adjustable struts with Heim Joints (no bushings-VERY IMPORTANT since this change is big reducing camber change during high speed corner-tires remain in the best geometry for adhesion) AND a GM FACTORY TYPE 3/4 inch rear sway bar to offset the 550 front springs and factory 1 1/8 inch front bar as well as Bilstein Sports-the 360 mono spring is actually too soft for the 550 front springs so……bigger rear bar. Result near neutral handling with SLIGHT oversteer at the limit which I much prefer than plowing into a guard rail nose first….

Fast Forward to today…Almost every sports oriented vehicle even most mass market vehicles have a front and rear sway bar including cars that are rear engined or mid engine which if you follow the logic on no rear sway bar on C3's for optimal handling should NOT have a rear bar since those cars would oversteer into the weeds and should only have a front bar to reduce the oversteer tendencies which is NOT the case. Manufacturers balance the handling using Springs and front and rear sway bars…clearly the best way to achieve neutral balance. Which brings me to the issue of "neutral" balance….Most high performance cars today are not neutral balanced. Pushed to the limit they will exhibit slight oversteer (which is the fastest way around a track including my 10Z06) and WILL exhibit trailing throttle oversteer (again the fastest way around the track)-neither two are BAD on a street vehicle as long as the driver knows what they are doing. A properly setup for optimum handling C3 will exhibit slight oversteer AND trailing throttle oversteer-probably not the best for most drivers but NOT a bad handling trait, again, if you are looking to maximize handling with a competent driver.

Lastly, my 10 Z06 and all C6Z06's have an oversteer trait at the limit. Using the rear sway bar methodology often referred to on the forum, the "fix" would be a smaller rear bar or no rear bar. Neither though in reality is the "fix". I minimized the issue with specially valved Doug Rippie Motorsports Bilstein shocks (awesome BTW) or like many do, go to a different sway bar setup (front and rear) with a MUCH bigger front bar and slightly larger rear bar.

Everyone should read this for a better understanding of springs, shocks and sway bars:

http://www.442.com/oldsfaq/ofsus.htm

 

We may be getting a little off from the original post. The original thought is just to get a little better handling for a street car. Race driving with experienced drivers is a little above what's wanted or needed. We all sometimes get influenced by the bigger is better idea, of if it's good for a race car, it should be good for me. I know I did. Even some of the dedicated vendors get carried away with this. Money wise, this could be a bottomless pit, and you may end up with a uncomfortable ride.

 

Unfortunately, sway bars and their effect on handling is not a simple yes or no answer which is often why there is so much confusion about this subject with no single right answer. One really needs to understand the whole story-handling effects of sway bars, springs, shocks, end links, etc^ especially the link attached in the prior post in attempting to answer the OP's question.

 

Very well put.

 

 

I have read everything here. some of it twice... I think at this time there is no reason to add the rear bar. the car will be driven for local rides and some stoplight rude behavior. I do not see me at the track with this car..

 

my car is street only however i can drive in excess of 100mph driving and getting off bank turns on parkways.on long island i will not get into what a parkways is lets just say they are car only roads with no distraction or intersections only grass and trees set way back i have change anti sway bars twice and feel slight oversteer with 7/8" rear bar and 1 1/8" front with sbc and a/c front springs.i had a bad experience with a 1982 at high speed the rear came around on me taking me off the road.i survive but car was damaged.you take that same turn faster and faster until she just breaks loose but in this case i could not get back on track.i like rear planted!!!!