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Weasel73240Z

Rear suspension upgrades

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Hey everybody! It's been a while. After just enjoying the Z for a couple of years, I'm finally ready to tear it apart again. At least the rear end. I just ordered a Suspension Techniques rear sway bar kit, and I'm thinking about strut/spring combos.

I searched a bunch of posts, but couldn't really find anything for my specific situation. The existing setup is stock (original springs, no sway bar), but the struts aren't original (but not done by me either, so I don't know what they are, or how old). A lot of what I read said that the rear sway bar alone would make a huge difference, and doing stiffer springs and new struts may make the car too stiff. I drive it pretty hard on the street, but I don't race at all. Right now, there's just too much lean when I corner hard, and my tires are occasionally rubbing. Anyone who ever lived in New England knows that the winters are real bad on pavement, and most roads around here are pretty bad.

If I do the springs, it would probably be Arizona Z, because I don't want the car any lower (Massachusetts streets). Seems I always get the right answer here, so what do you guys think? Should I do all it now, or do the sway bar now, drive it in 2011, and decide if I want it any stiffer? Keep in mind the New England streets. :angry:

Also, if you think I should do it all now, any strut recommendations for my type of driving? Thanks!

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To keep a Z from leaning, there are a few bolt-on methods. Stiffen the springs, thicken the swaybars, and for added measure you may add poly bushings to the sway bars. I don't think there is any bolt-on method designed to keep the car flat, that will not trade some ride comfort. Not with this old suspension system.

Having said that, I highly recommend a staged upgrade path.

1)larger diameter wheels with lower tirewalls.

2)Stock swaybars with poly bushings or new rubber bushings.

3)Heavier swaybars with poly

4)An aftermarket spring and strut cartridge setup.

5)Coil over setup to really dial in height and still maintain the correct suspension travel.

Make sure you don't upgrade only one end of the car. Do it as a full setup.

Some people like heavier spring/strut and softer swaybars, some like the opposite. It's a matter of personal preference.

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The swaybar is a relatively easy part to remove, so maby its better to go sway bar first and decide on the struts and springs later. Could be that the SB will give you what you want ans save some dough for the five dollar gas that we will be burning soon.

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Keep this in mind as well. Stiffer springs and sways will put significantly more load on the tires, make sure your tires are up to the challenge of handling these extra loads. Meaning good compound, in good condition, with good traction. It is called a suspension system for a reason.

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I'll echo 5thhorsemann, do the swaybar by itself first. Then decide on any future upgrades as recommended by Dave.

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Installing a large rear sway bar without increasing your front bar will provide you with some fun times this coming driving season.

But way before you install the bar, which is a good idea on a street car, the issue of shocks and springs needs to be addressed. Just replacing whatever you have with a set of 5-way adjustable and non-progressive, linear springs (my own $00.02) should give you a firm but nice ride feel. Replacing the old rubber bushings with poly (except the steering coupler) will make your 240 feel like a whole new car.

As to driving your Z up here in MA, my 240 sits on 275lb springs w/Tokico HTS shocks, ALL poly (coupler too), large sway bars, coilovers and is all of 5.75 inches at the rockers.

Stiff? Yes. Ride? Like a flipping dream, but each to his/her own style and comfort level.

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Also be aware that adding a rear sway bar will increase the tendency to oversteer or, conversely, decrease the tendency to understeer. I agree that a decent sized rear bar, say 3/4" should be accompanied by a front bar of at least 1", perhaps 1 1/8".

As Zedyone said, it is a system, and each unique change can present what is known as "unintended consequences" in the car's handling characteristics.

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Adding a rear bar only will not help a lot. Increasing the front bar and add the rear bar in concert will work best.

A new street style progressive spring strut combo will make a lot of difference. JMHO, Richard.

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Thanks for all the input guys. I'm leaning towards just doing the SB for now, and then deciding. If I lived in LA with nice streets, I'd probably do it all at once. But I think I like the staged approach, and I'm always looking for a project anyway!

BTW, we got a foot of wet, heavy snow this morning!! :mad: Awesome.....

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I finished the Suspension Techniques rear sway bar install this weekend. What a simple and clean install! Took me less than 3 1/2 hours total, and 2 of those hours my buddy was standing over me, talking.

I only took the car for a very short ride, since I discovered a rotted out front sway bar end link bushings during the inspection, but it felt like there was less body lean. The car sits about 3/8" higher than before the install.

And I went through my notes and discovered that I replaced the rear struts last year, and forgot about it. Good thing I write stuff down! :stupid: Gonna stick with the stock springs for this year.

Also threw in a pic of my RT mount...anorther great upgrade...no more clunk!

On a sad note, my Z is going to hit 30,000 miles early this year.....:disappoin

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Installing a rear sway bar should not make you ride any higher. That is strange. Perhaps since the car was jacked up and the suspension was unloaded the car just sits higher since the struts were fully extended. That close clearance spooks me. I guess It is designed to work.

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Having installed a similar rear bar last year I would suggest adding a spacer to move it about 3/8-1/2 inch back on the carrier legs. Note the angle of the link ends and then consider that angle at full compression. I used two pieces of metal with a cut out tab at end end to hold them in place. Drilling them out will do as well.

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Having installed a similar rear bar last year I would suggest adding a spacer to move it about 3/8-1/2 inch back on the carrier legs. Note the angle of the link ends and then consider that angle at full compression. I used two pieces of metal with a cut out tab at end end to hold them in place. Drilling them out will do as well.

I though it seemed like the end link was leaning a bit forward, but I figured it was engineered that way. So you put spacers between the new suspension hangers and the sway bar brackets? I see how that would take the leak out of the end link. Did you have a problem with them, or did you just do it because the angle of the end link concerned you?

I have some time, since I have to wait for my new front end link bushing kit to arrive. I guess I should mock up some spacers. Thanks for the input.

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Installing a rear sway bar should not make you ride any higher. That is strange. Perhaps since the car was jacked up and the suspension was unloaded the car just sits higher since the struts were fully extended. That close clearance spooks me. I guess It is designed to work.

It only lifted it about 3/8" (from 24 5/8" to the wheel arch to 25" after the job), but it does make sense, I think. This is after a 2 mile drive, so everything was settled into place. I always thought my Z had a slight sag in the tail. Now it has to extra strength of the rear sway bar factored into the mix, so I expected the rear would lift up slightly. Just one more rigid member holding the arse end up, or so I assume.

The clearance is spooky, but since everything moves in concert (the sway bar end links and half-shafts are both connected to the lower A-arm), I think the clearance is pretty much a constant.

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An ARB does not nor should not affect ride height, unless it is binding somewhere which would not be good. The only time the ARB comes into play is when the ends are deflected, meaning it only applies a force when one wheel moves with respect to the other wheel. It should not be weight bearing.

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An ARB does not nor should not affect ride height, unless it is binding somewhere which would not be good. The only time the ARB comes into play is when the ends are deflected, meaning it only applies a force when one wheel moves with respect to the other wheel. It should not be weight bearing.

Nothing is binding, I can move the rear end by hand, by pressing up and down on the bumper. But if you look at the end links, they are leaning, and as Gnose pointed out, that's not good. I suspect the leaning end links could be restricting the rear end from settling all the way down, which may be why it is 3/8" higher now. I bet when I put in the spacers, the 3/8" will be gone.

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I would be cautious in going 100% poly. What you have is a 38 year old structure that has seen its fair share of transient loading and vibration. You might want to keep some rubber in key locations on all corners to allow some pliability. It seems you're building a street car, so I would be careful about stiffening the springs too much. Remember, the Z didn't have a Cadillac suspension to start with. Stock doesn't mean soft, it means a lot better than the worn out suspension you have now. Few people on this site even know what a stock Z rides like, including me. That being said, stock springs are not available from any store or website. We once had some made but to my knowledge they were all sold. You can check with Courtesy Nissan to see if they have any of the Euro springs left, that we had made as well; I don't know if they do. I'm not trying to push a stock setup for everyone, but there was a time where everyone was taking their beatup old Z from worn out to track stiff and lowered, and were later sorry they did. If you're racing and autocrossing a lot, there is no question what you should do. If your driving pothole ridden America, think twice before you make big leaps.

Cars built today are far more rigid and heavier as a result. You can't treat a Z like those cars. You have a 2400 lb GT, not a Formula 1 racer.

I'm building a road car for taking trips, etc.... so I installed new stock springs, stock-type shocks, some poly and an upgraded fr/rr anti-sway bar kit. You might be able to deflect a corner of my car by an inch if you lean on it.

That's my 2 cents. Good luck.

Edited by bpilati

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I'm putting urethane in the front end link bushings. All of the other mounts are stock rubber. My springs are all stock, 38 years old.

Also, my Z only has 29,000 miles on it, 26,000 of them put on by one owner, a very nice old lady from Hopkinton, MA. The other 3,000 were me. Before I started changing things, everything was 100% stock, down to the radio. So it hasn't really been stressed at all, and I have a pretty good idea about how a "stock" Z rides. It certainly isn't a beatup old Z! ;) If my Z had 129,000 miles I'd be concerned about over-stressing it, but this car is barely even broken in, so I think the unibody can handle it. And I don't drive it crazy, just like to push it occasionally.

Once I replace the front end link bushings, I hope I'm done with the suspension changes. Thanks for the input.

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Hello,

Yes you are right. i also just changed my sway bar and control arms and they gone because of bad roads. i bought them form this ebay store on very reasonable rates. and now they are working great.

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