Rear Sway Bar Mystery

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NewSixCoupe

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Car is in for a complete rear suspension overhaul and my mechanic has discovered the absence of the rear stabilizer bar. He cannot remember seeing a coupe without one, but also says that there is no visual evidence of one ever being on the car. Only caveat is the presence of undercoating which was applied when the car was new and could possibly be hiding something, but why would someone remove the sway bar back in '74? Car has Bilsteins, but they were installed later...

Did certain late production US-spec. cars come through without a sway bar?

Thanks!
 
Thanks, David. Did some additional research and the consensus seems to be that it was typical of late US cars to not have a sway bar, although the mounting points are there... I guess the next question is whether it makes sense to add one?
 
Hi Len. My 74 CS also came without one. All the mounting places are there however. I was told that the luxury-idea was to give the car more movement in the rear, but it could have been one too many biers or short on supplies. Regardless, the stock rear sway bar is very thin so with the Bilsteins you would probably want a stiffer bar. I installed an ST front and rear bar set (rear is "adjustable"). -cost- approx. 350.00-I can not provide the results because soon after I installed the bar (and this is typical for me) I ripped out the rear end to weld on camber/toe adjusters. It's going to the alignment shop tomorrow morning so hopefully I can report the results.
 
Thanks, Peter. Its not really holding up the progress of the other suspension work, so I'm leaning towards leaving things as is for now, especially in light of your comment about the bar size relative to the Bilsteins...

I do like having the option to add it later.
 
In the rear axle section, the repair manual references them leaving the factory without:

"Supports is stabiliser bar is to be fitted after car has left factory"
 
Our Coupes tend to kick out the rear when pushing it in corners. Adding a rear sway bar would only magnify this tendency. I added a stiffer front sway bar (from a Bavaria) and it reduced body roll and stabilized the over-steer somewhat in corners. This was for use at high speed driving school on various tracks with the BMW club. I would not test it on the public streets!
 
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Stevehose said:
In the rear axle section, the repair manual references them leaving the factory without:

"Supports is stabiliser bar is to be fitted after car has left factory"
Click to expand...

"...to be fitted..." based on what? Dealer discretion? Owner preference?
 
Len: my '74 CS had no rear bar, but the mounting brackets were there. The '75 CSI barn-find that Steve and I parted out had a rear bar, so I installed that on my car. Not sure it made much difference as I haven't really tested it out, but it came from a CSI and now it's on my car, which I dub a CS(i)...
 
FWIW, my Bavaria came without one but all the fixins to put one in as it was an option. I did not go nuts and use a ST bar but ordered a factory OEM one with the fittings and bought the sway bar links from Ireland Engineering. Don't know about the e9 but I really noticed a difference in my e3...and I don't drive crazy. The difference was appreciated in everyday traffic. All told it was about 120 dollars for the bar, hardware, bushings and links. Good investment from my POV.
 
Hi Bill, and thanks everyone for the insight. Picking the car up later today so I'll first see how it feels without 40 year old rubber! I'm leaning towards adding the factory bar and will see how the car feels with it and the Bilsteins...
 
bill said:
Len: my '74 CS had no rear bar, but the mounting brackets were there. The '75 CSI barn-find that Steve and I parted out had a rear bar, so I installed that on my car. Not sure it made much difference as I haven't really tested it out, but it came from a CSI and now it's on my car, which I dub a CS(i)...
Click to expand...

Was the '75 CSi barn find the Connecticut car?

To keep on topic I installed Bilstein HDs and the ST anti-sway bars from La Jolla Independent. Greatly improved the handling of the car. Went from a floaty Buick to a firm predictable well handling BMW in a day.

If anyone would like the stock anti-sway bars, I'll sell them inexpensively.They are just sitting on a shelf.
 
gwittman said:
Our Coupes tend to kick out the rear when pushing it in corners. Adding a rear sway bar would only magnify this tendency. I added a stiffer front sway bar (from a Bavaria) and it reduced body roll and stabilized the over-steer somewhat in corners. This was for use at high speed driving school on various tracks with the BMW club. I would not test it on the public streets!
Click to expand...

In some instances a stiffer bar on an independent suspension rear axle will reduce the oversteer by reducing the body roll and maintaining a better camber angle on the rear tires. We experienced this in our 65 Corvette that we ran in the Lacarrera Panamericana.
 
Adawil: no, it was an NJ and RI car. Spent way too much time in RI to the point where any aluminum on the car (e.g. the engine) was pitted by salt corrosion. It then sat in a barn in NJ for years and was covered in bat guano when we found it. The body was too far gone to keep. Too bad because it had been sent back to BMW (!) for substantial frame and rust repair only to return to RI where it happened all over again. But it had some great parts including front and rear sway bars and other parts unique to the CSI.
 
Mike Goble said:
In some instances a stiffer bar on an independent suspension rear axle will reduce the oversteer by reducing the body roll and maintaining a better camber angle on the rear tires. We experienced this in our 65 Corvette that we ran in the Lacarrera Panamericana.
Click to expand...
There are exceptions to every rule. After racing with SCCA since 87, I have learned it takes a lot of adjusting to get a good balance with suspension. That adjustment seems to be never ending in seeking the optimum setup.

The general rule is softer (springs, anti-sway bar, tires, etc.) make the grip better. There are many other factors that limit how soft or hard the suspension should be. Body roll is definitely not good for fast cornering in good grip conditions but in conditions with less grip like rain, it can improve lap times.
 
My intuition was that the harder the suspension the less one needs the sway bar. Did these 74s come with stiffer rear suspension that 72s for example?

The fascinating part is that as we go deep into exhaust, suspension, cams, and of course carbs I learn that each of these areas is really an art and not just a simple cost/perfomance tradeoff. In other words, it takes gurus not just financiers to get a refined result.
 
Arde said:
My intuition was that the harder the suspension the less one needs the sway bar.
Click to expand...

That is basically true. However, I have seen some racers that like softer springs with a stiffer anti-sway bar. Everybody has their own preferences depending on their particular style of driving.
 
I have been reading -with great interest-both this thread and the responses to my post regarding rear suspension; agreed that there is a great deal of "art" involved in all aspects of these cars, I think that's why we as a group are so attracted to them. I also think there is a "science" involved- that's what I'm searching for in the rear suspension. Softer springs/stiffer shocks/light sway bar/so many degrees of (-) camber/toe-in, etc. or vice-versa. The posts on this thread are not confusing in themselves but certainly cover allot of variables and differences of opinion and correspondingly different results. My goal is to come up with a set of guidelines or a starting formula much like we tune our carbs (if so equipped)- start with the mixture screws seated and back out... and all the variables such as properly seated bases, throttle plate position, etc....

So, assuming our cars have not been crunched or distorted our variables effecting ride and handling under "normal" conditions would be;
Spring Perches
Bushings
Springs
Shocks
Sway bar (if installed)
Camber/toe plates (if installed)
Wheel size
Tire size/type/pressure

I guess I could add shock tower brace and coil-overs but I think that would be a track set up as opposed to an all-around maybe aggressive driving machine.

Would anyone care to postulate a formula using the variables above? Maybe we could come to a consensus that would be of use. Again, the set up would be different for track days, but I would love to know what people who drive "creatively" feel is optimum. Also, if I missed any variables please feel free to add them.

Indebted-in-advance (as always)
 
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