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Phantom

Suspension Techniques vs MSA Sway Bars

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Maybe not everyone's bench racing logic, but you're not the first person I know to have ditched the rear bar due to excessive oversteer. 

 

Would that oversteer be from an improperly balanced/setup car or from a lack of right foot control/calibration on the accelerator pedal?  :D

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A few years ago my thinking moved away from a bigger rear bar.  A lot depends on what type of rear diff you're running.  With a welded diff you need a bigger rear bar to get the car to rotate under trail braking.  With a good clutch pack LSD that has a low breakaway or a ATB you want a much smaller rear bar.  IMHO, the S30 will turn faster lap times with more roll stiffness up front.
 

Toward the end of the RODs life with me I was running a Quafe ATB and a 1 1/8" front anti-roll bar and a 5/8" adjustable rear anti-roll bar set at full soft.  Springs were 375 up front and 300 in back.  The car felt dead and pushy on corner entry but came out of corners hard with a nice set.  Lap times improved.

 

For a street car things are different.  You can't run enough spring on a street car so you need a bigger anti-roll bars.  Also, people without much racing experience confuse a neutral handling car with an oversteering car.  A neutral handling car will step out in back if you lift off the throttle in a corner.  An oversteering car will step out in back in a corner - period.

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I do have to say that my experience is dialing in the car for best handling in autocross, hillclimb and road course in a street/track car over the last 20 years and driving at 10/10ths.  Most won't ever drive there cars to the limit to find where a single setting on the swaybar makes a real difference and John's comments on the other end of the spectrum is right on.  Driving style, type of driving and other factors like camber settings and shocks will also have a big impact on what kind of bar is needed.  I've often run a stiff front bar, but with rubber end link bushings and quite a bit of negative camber to get the handling I like from the front. 

 

Another point to bring up is that the diameter of the bar is not directly related to how it works when comparing the front mounted 280Z rear bar to the rear mounted 240Z rear bar, as length of the "arms" relative to the distance from the mounting/rotating plain will also dictate the true stiffness of the bar.   Smaller is not always softer. 

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Would that oversteer be from an improperly balanced/setup car or from a lack of right foot control/calibration on the accelerator pedal?  :D

Gary - I can confirm that oversteer in my car is all throttle related as I did it both by lifting my foot and by pressing it down in corners. My understeer was braking and boy was that exciting. Under light throttle and entering the corner at the proper speed the car would do really well.

With a rear weight biased 3,000 lb car and 200/250 springs I think the heavier 280 bars F/R will be the way for me to go. My stock sway bar is already installed in a manner to handle my exhausts and the finned R200 LSD so hopefully the ST bar will bolt right up. Need to stick my head under there and study it a bit more.

The autocross day was the first time in 22 years that I put the handling of the car to the limit and actually hung the rear end out in a corner other than just goosing the throttle at an intersection. I need to get it sorted out as I really want to do some more of this but it's going to take some work.

Edited by Phantom

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Gotcha.  Did you ever go with adjustable control arms to you can play with camber front & rear?  Camber & toe play a big part and then you have tire pressures to play with, as well.  Did you mark your tires with white shoe polish to see how much tire roll you got?  Having autocross for 12 years in the Pacific Northwest, there are many great events to do up there. 

 

My ST rear bar just showed up, so I'll get it in this weekend along with the Techno Toy Tuning rear arms to get it adjusted right.  Front already has adjustable arms & T/C rods.  I'll give an update on how the bar mounting works in consideration to the setup we both have for the finned cover. 

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Nope, haven't done that yet. Things have really slowed down with the Z since I moved to WA. Way too many other things going on. Income has been stressed with the house addition and other property upgrades so car has taken a back seat. I just got the Techno Toys Eibach coil overs and Koni shocks last summer. I want to get whatever it is with my drivetrain fixed, my brakes sorted out, and then get the sway bars in. After that I'll look at the adjustable control arms and T/C rods.

I didn't remember the shoe polish trick when I went. I will next time. Then I'll see how much rollover I'm getting at various pressures. I looked at the side walls on the tires at one point but didn't see anything definite.

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OK, so I put the ST rear sway bar (for 240Z #51075) on my 280Z with R200 CSLD w/ finned cover.  It fit without any fitment issues, but I do have to fab up a new diff brace since the sway bar runs across part of the same area.  I've got 2 different ideas on how I'm going to do it and neither are that difficult.  Here are some shots.

 

 

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What was the clearance between the rear differential mount and the bar, differential cover and the bar? It looks like they are really close.

I tried to take a quick peek at mine yesterday and all I could see is that my sway bar is in front of the differential rather than behind. I need to get the car up high enough to look at it to really see what is going on under there. It's been 10years since I really looked at that and my memory is a bit fuzzy.

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No clearance issues between the sway bar and the diff cover. There is about 3/4" clearance from the flat part of the mounting section of the transverse link we still have, but the diff brace is 1" wide, so "No Go" there. If the brace was 1/2 the width, it would work. I'm currently getting the new brace solution made up. Will keep you posted.

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Gary,

My bar is in the stock location and runs on the front side of the differential rather than the back side. See photos. In that position I don't see any issues with running the ST sway bar spec'd for the 280, do you?

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If you are wanting to just go with the thicker bar in the stock location (front mount), then you should be fine.

 

The reason I went to the ST 240Z rear mount bar was to give me more clearance at the rear crossmember. I added a 2nd notch for the dual exhaust and the MSA rear 280Z rear bar ran right across part of those notches. While the 240Z bar is smaller, is doesn't need to be as think since it is shorter. It's a leverage thing. Here are pics of both away bars MSA 280Z & ST 240Z. I never ran the MSA bar, so it's going on eBay now that I've got the other setup.

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Edited by Savage42

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Ok, so I got the rear setup installed with a new transverse link arrangement that allows the use of the rear mounted 240Z rear sway bar in a 280Z with R200 with finned aluminum cover. I am making up a second link like this and will post a dimensional diagram for anyone wanting to make their own. Here you go.

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Thanks, Bill. I've got a 2nd brace that I'm adding to a modified stock brace that keeps part of the original material across from one side to the other and not just the center section cut out. Stay tuned for pics if that version. At least we have another option for a brace.

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I currently have some old Mulholand sway bars on my 73 240z.  I want to get the ST Front and Rear swaybars.  I have a '82 R-200 dif and correct mustache bar mounting it.  When I jack up the Z with the wheels off the floor, the rear sway bar ends rub on the half-shafts.  Therefore, I can not put the car in gear while up.  This is one of the reasons to replace the old Mulholand sway bars and also finding the correct sway bar mounting bushings.  Will the ST sway bar do the same when the Z is jacked up with the wheels off the floor?

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I had one of the old Mulholland bars at one point. Can't even remember why I had it, was a long time ago, but IIRC it was really very similar to the rear mounted ST bar. One thing not mentioned previously in this thread is rebending the bar. I found that my ST bars bent very easily with my HF press (12 ton I think). You might be able to modify the angle in the arms to get clearance and make it work. Literally just took the bar, laid it across the table part of the press, then jacked the jack into it and bent it that way while holding onto the bar. Surprisingly easy.

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