My car is a 76 280 Z.. I have searched numerous forums regarding rear "sway" or anti-roll bars. The trouble I'm having is that I've been running without one for years now due to my left side sway bar mount being broken off from the body twice.. when I bought the shell it was broken, and I had it re-welded in the stock location, then it broke, so I left it off. Now I'm autocrossing on a regular basis, and think I should be running one. I really like the idea of running the bar behind the rear end, but the only kit i've seen is from arizonazcar.com, and looks like a beautiful piece, but too expensive for me. I've found posts talking about the Suspension Techniques bars coming with different uprights to mount the bar behind the diff, but everything I've read lists different part numbers for 240 Z's and 280 Z's.. will they interchange? I understand they list a different kit for the 280 since it came factory with a rear anti-roll bar, but can I use the 240 kit to reverse mount it? My second question it should I even worry about it? I've read on some other forums that cars with open diffs tend to be faster without them since there is no roll bar acting to reduce weight on the inside rear tire causing wheelspin? Any merit to that theory? Sorry for the long post...your thoughts are greatly appreciated..

There is merit to the "no lift on the inside wheel so less tirespin" theory, but if you are running streetable spring rates the bar is more helpful than hurtful. If you're running really really really stiff springs, then you can ditch the rear bar. That's my opinion anyway.

Get the 240 rear bar and space the bar away from the uprights about 1/2" and you should be good to go.

I'm with Jon on this. I tried disconnecting the stock rear bar for auto-crossing my old graymarket BMW 323i - one time. I was, like you mention, attempting to reduce inside wheel lift and wheelspin. It did help with wheelspin, but it messed up the handling so bad (pushed hard) that I reconnected it before the next run.

In the end, I swapped a limited slip into that car. That was the ticket, made a huge difference.

I love moderate springs and heavy bars. Makes for a streetable car that handles very well at an autocross. I say use the bars...

I've been waiting now for 2 months for my sway bars to arrive from Motorsport. According to them, their rear bar does not use the stock mounting location on the frame-they say you need to drill holes to install it and that the location for their bar "provides better support". Since I don't have it yet I can't verify this, but you may want to call them to see.

In the end, I swapped a limited slip into that car. That was the ticket, made a huge difference.

Agree with this too. The LSD is a major factor, with one you can accelerate much harder out of a corner.

thanks for the replies guys.. I don't have extremely stiff springs at all on the car now.. In fact the rear springs are stock and the fronts are tokico progressive rate.. ( I got them in trade for some 280 injection parts ).. Anyway, I can use the 240 bars then? What about the front one? Also can anyone confirm that the ST kit comes with the new uprights for the 240's? Again, thank you and any other input is greatly appreciated..

The ST kit comes with new transverse link braces.

For a lowered S30 The rear mounted ARB has better geometry then the stock bar mounting location unless you're willing to space the stock location bar down 1 to 1 1/4". But, that interferes with exhaust system routing out the back.

I would use the front 240 bar as well. The 280 bar is really big and can tear up the frame rails because it is so stiff.

When it comes time for springs, I'm guessing that won't take too long, get coilovers. Gives you a lot of freedom, you can pick just about any spring rate in 25 lb increments.