Rear sway HELP

[buZy]

Do I need to run a rear sway bar in my 240z?

 

This is a Street Car....(but keeping in the idea of a well handling Z)

I ask for the one in the car now is a 280 forward mounted style and who ever mounted it was a complete idiot... Sorry to put it that way but it's so true. It binds and I think as of now its doing more harm than good. The pivot bushings last no more than a few hundred miles and it makes a ton of noise.

The rear suspension is so tight/stiff and does not respond to changes compared to the front.

I noticed my stock 71 oem service manual show no signs of a rear sway bar.

 

But it seems some early 240z cars had a rear mounted sway bar mounted to the two downbraces for the rear suspension pivots. Correct??? Or is that wrong?

Could I mount one there and still have it clear the stock z half shafts? Also have it fit between the r200 lower horz brace and M-bar? (see pic)

 

It's hard to put this problem into words.

I know every car is Different to say the least.

 

I post this thread because you can see in the pics I will have to CUT OUT the sway bar to remove it from the car or cut the frame..... Not good.

I don't know how to resolve this problem.

Any help at all would be great. Thank you all.

 

A list of parts...

Car is set 1 inch lower than stock ride height.

Adj coillovers 225 Front 10 inch / 250 Rear 10 inch

Illumina adj struts. Non sectioned with good bump stops.

AZC front CroMoly Arms typical.

Front LCA pivots up .750 only

Biscut street camber plates all 4 corners.

Stock 240z front sway.

Stock rear arms with Poly bushings.

AZC billet M-bar

r200 from a 78z open diff.

 

[Guest speedmon]

I think the main purpose of the sway bar is to reduce body roll. I had a fat one on the front of my 240, but my car was understeering so much it was scary....literally! I disconnected one side of the front bar and handling improved, ALOT! Needless to say, I am now running without a front sway bar and the car will outturn just about anything at the track.

 

Try disconnecting the bar and see how it handles like that. With those 250 springs, you probably don't have much of a body roll issue.

[JMortensen]

Looks like a tight spot you've got there. No room to mount below the subframe connector, and binds above, huh? Well, you could go to the rear mounted 240 bar. My front mounted 240 bar from MSA bound like crazy too, FWIW, so I switched to a rear mounted bar. Quick test for you would be to disconnect one end link and see what happens. Won't fix the bind, but will eliminate the sway bar aspect. You can drive it around a bit and you'll feel the effect anyway.

 

As to whether the rear bar is "necessary"... well not required in absolute terms, but it can definitely make a pretty drastic difference on the balance of the car. If the car pushes a lot when you take it off, then you'll want to consider some alternative like the rear mounted 240 bar instead. I'd also take a look at the front bar. If you have the 280 front bar at 1 1/8", then you'll probably need something out back just because the front is so freakin huge. In that case you might consider a smaller front bar, like the 1" or maybe even smaller.

[fastzcars]

But it seems some early 240z cars had a rear mounted sway bar mounted to the two downbraces for the rear suspension pivots. Correct??? Or is that wrong?

 

The rear mounted sway bar is actually made by "Suspension Techniques" the kit comes with new Uprights with holes drilled in it already for the polybushings. They come in either a 3/4 or a 7/8 inch size bar.

But since you have 250 lbs springs you MAY not need a rear bar. It's up to the way YOU LIKE the way the car FEEL's to you. Some people like a loose car, some like it tight. Try removing the rear bar first and see if you like it before you put down $200 for a ST bar , they you may remove later.

[JMortensen]

I think the ST bar comes in 3/4 for the rear mount 240 version, and 7/8" is the front mount 280 version. 99% on that, but not absolutely positive.

[buZy]

Wow! Ok cool idea! Now I feel dumb guys I didn't figure that one out before. It seems somtimes the simplest of ideas are so easy over looked. I will try disconnecting one of the end links and see what happens. Almost scared to see what happens.

Personally I prefer a slight oversteer loose feel when the car is in full drift. Grew up in MN winters where you learn to corner with the throttle when the front tires almost become useless braking on black ice. To this day I refuse to buy a front wheel drive car for that reason alone.

 

Anyways...

With how stiff the rear is the front really works well in reguards to changes being felt. Hard to explain it but the rear is so stiff it feels like once it does give way at higher speeds it will do so without warning. I don't trust it. Hope all my settings up front will not alter too greatly once I unbind the rear bar. We will just have to see. It would amazing if I could just ditch the bar and not have to spend a dime. I never get that lucky.

 

FWIW...The front stock 240 bar is small measures .725 in diameter.

Would think if I ran a rear bar it would have to be even smaller right?

And if so, to what effect would it have being so small in diameter?

Why are all these aftermarket sway bars so huge?

Maybe for unique situations in racing ok, but the major market share is guys like me just doin the street thing.

[fastzcars]

FWIW...The front stock 240 bar is small measures .725 in diameter.

I would think if ran rear bar it would have to be even smaller right?.

And if so, to what effect would it have being so small in diameter?

Why do all these aftermarket sway bars are so huge?

 

I guess that's why the factory didn't put in rear sway bars. Your also correct in that with a 3/4 inch rear bar, the recommendation is to install a 1 inch front bar to balance out the car. So with that said, your small front bar will probably go well with NO rear bar setup.

 

Oh one more thing, Tires will make a HUGE difference in the way the car behaves. Just keep that in mind.

[thehelix112]

My 240 came with a rear bar?

 

The sway bars, in conjunction with the springs (amongst other things) affect the amount of body roll you will get during cornering.

 

The relative roll distribution front to rear determines the balance of the car, ie, which end lets go first. Thats about it really. FWIW I took my front bar off to get the chassis rail repaired, oversteered like nothing else.

 

I would recommend adjustable bars so you can tune the roll distribution/car balance to your liking.

 

Dave

[Clifton]

Personally I prefer a slight oversteer loose feel when the car is in full drift. Grew up in MN winters where you learn to corner with the throttle when the front tires almost become useless braking on black ice. To this day I refuse to buy a front wheel drive car for that reason alone.

 

Taking the rear bar off will reduce oversteer. Also you can set up a FWD car to be loose.