rear sway bar install

[csedatsun]

OK,
I shouldn't have done it, but now I have it. Who has info on how to mount a rear swaybar? I bought one on ebay, it has most of the bits and pieces, but nothing to hold it to the rear axle or the body.

[mgslayer]

I won't say if this is right or not, but this is how my parts car has it's rear sway bar mounted. The sway bar looks like it is attached to the axle using muffler clamps with a bracket that holds the sway bar in a bushing similar to the front sway bar. The front ends of the bar are attached to the body right in front of the shelf with a bolt, with a bushing between the sway bar - car body - another bushing and a nut. Hope this helps. http://www.311s.org/phpBB2/album_person ... ser_id=342

Let me know if you want any other pics

Happy Wrenching

Mark

[SLOroadster]

I really hope your car plows through corners, because mine was a serious handful with mine attaced. It was scary. I've been tempted to reattach mine with better tires, but have been too scared to.

just my $.02,

Will

[mgslayer]

Will

Since you had one attached, does mine look right? I might take it off the parts car and try it on my Beast one day.

Thanks

[ppeters914]

Okay, I'm a newb on this stuff. I'm assuming (yeah, yeah, we all know what that means) that sway bars prevent sway. Is that correct? What determines if it's needed or not? Pros & cons?

Just curious.....thanks.

[toolsnob]

A rear bar can be a detriment to the handling. Case in point I have had 2 roadsters 69 and a 70 with one. Both had complete comp suspensions front/rear with gas adjusts, the 69 had cheap tires and responded well to the bar, my 70 on the other had is running A0032R's and the bar actually worsened the handling causing my front end to push. I am going to remove the gas adjusts and replace with GR-2s, which should help and make the bar effective and the car ride better with the stiff springs handling more of the dampening than the stiff shock.

You will need to order a new swaybar mount kit or bar, a new bar through nissan is $200. I have just spaced the name of the company that makes them but the name starts with an A I believe. They are on the internet

[spl310]

Addco

[DatsunBucky]

ppeters914-

The object of a "sway bar" (it really IS an anti-sway bar) is to transfer up or down suspension movement on one side of the car to the other. The thicker/stiffer the bar, the more energy is transferred. This keeps body lean to a minimum and lets the tires more evenly share the workload. When the suspension on both sides moves the same distance and direction, the bar just pivots in its mounts, regardless of the stiffness of the bar.

Everyone has a different driving style, and while one driver might not like the handling of a car with a rear bar, another does. I personally fall into that second camp. When I was autocrossing my first Roadster back in the 70s, I had the full factory competition set-up, including the factory gas shocks and a 4.38 LSD, along with a rear bar I got through JCWitless. Backwards from today, the middle of that bar attached to the axle and the ends of the bar to the frame behind the axle. I had to fab the frame-to-bar mounts because the ones they supplied didn't fit. Interestingly, that bar was also made by ADDCO. I really enjoyed the oversteer that resulted, and I'm doing that set-up again with this, my second, Roadster, but I've had to go with the KYB GR2s because of the lack of availability of Nissan or Koni shocks. Side note: the rear shocks feel OK, but the front feels way underdamped with the Datsun Sports springs.

Anyway, it's Anecdote Time! (What else would you expect from an old f*rt?) Worst oversteer EVER: real racing tires (NOT just R-compounds) in the front (couldn't change them after an event due to a jammed lugnut) and street tires in the rear with the rear bar. The car oversteered sitting still! (Well, not really.) You LA guys, you know that transition road from the northbound Harbor Fwy to the westbound Hollywood Fwy? YEEEE-HAW!! Freeway speed. The car had at least 110% of my attention!

Back on topic, a rule of thumb used to be that adding a bar (or going to a bigger one) at one end made the other end stick better. I'm sure it's more complicated that this, but it helped me to remember how it worked. Bigger in the front=more stick in the back=understeer. One in the back=more stick in the front=oversteer. Both=higher limits.

[ppeters914]

Thanks, Bucky, that explanation really helps.

I plan on installing KYB GR-2's and Mike Young front springs as the existing shocks are shot and I'd like to lower the front. I've since learned that my rear leafs need to be rearched or replaced w/ the comp leaf (and what're the differences on that?).

I like to dive into the corners and twisties (blame it on motocycles and the Porsche 914), but no plans to autocross or get too stupid.

So, do I need to a) replace/upgrade the existing front anti-sway bar, and/or b) add a rear anti-sway bar?

Thanks. Roadster People Rock!

[nomadtrash]

The rear sway bar on the roadster causes it to lift one rear wheel off the ground during cornering. If you have a limited slip then you still get a little traction on the one tire that is still on the ground. If you have a standard differential then you will get lots of wheelspin and loss of rear traction. The solution to this problem is to limit body roll. This can be accomplished with stiffer springs or a larger front roll bar. The idea with roll bars is that you tune the handling of the car by stiffening the roll bar at one end or the other. To get the handling right on the roadster you need a very large front bar and a very small rear one. The Comp 22mm swaybar and the addco 23mm units are not large enough to balance out the Comp or Addco rear bars. With the rear bar installed the car will have good front stick but really lousy rear stick. It makes for an exciting drive because you are fish-tailing all the time. It is definately not the safest or fastest way around a corner. I guess if you wanted to build a Drift car then the rear bar would be the hot ticket.

I saw the photos of the rear bar mounted to the floor pan. It kind of scares me. The ends of the bar need to be mounted to a hard point on the frame.

[mgslayer]

That's why I asked if it looked right. Maybe if there were plates to sandwich on top and bottom of the floor pan to stiffen it so it couldn't possibly get pulled / pushed and strech the metal. The inside would be easy, just get a piece that would fit from side to side so you wouldnt see any bumps from using 2 seperate pieces, the same for the bottom. What I was planning on doing was having some tabs welded to the frame if I was going to use it. First things first, need to finish it up and get it running and back on the road. Thanks for the info

Happy Wrenching
Mark

[SLOroadster]

Mine is different. I don't know if yours is mounted correctly or not.

Will

[csedatsun]

Well, there has been some lively conversation on this subject. Just as an FYI, I have a larger front bar, stock springs and Koni's on the front, LSD in the back with KYB gas adjust. I have a pretty good thought on how to mount this puppy, and I will let you know how it handles from there. Thanks for all the input.
Chris