Does anyone know the specs for the OEM sport-tuned suspension sway bars? Size? Hollow tubes?

 

I'm pretty sure they are hollow.. i have no clue on the size and the rest of the specs.

 

http://my350z.com/forum/showthread.p...light=hotchkis

you can do some simple math to figure out the stock spec
Mike

 

All G35 and 350Z oem sway bar specs follow a more complicated path then Hotchkis's limited sampling, thus they aren't telling the whole story.

I can specifically fill in the gaps.

Group A

03-04 350Z all trim levels (car's without the revised suspension ONLY)
03-06 G35 coupe (all USDM production with oem 17 and 18" wheels)
03-04 G35 sedan (sport and non sport suspension's
All group A car's have the following oem sway bar specs
34mm front 21mm rear
hollow wall construction 5mm in thickness (courtesy of tomsn16)
Torsional rigidity Front: 1130lbs Rear:385 (courtesy BJ EVO350)

Group B

04.5-06 350Z all trim levels (car's with the revised suspension)
05-06 G35 coupe (all USDM production with oem 19" wheels)
05-06 G35 sedan (sport and non sport suspensions)

34mm front 21mm rear
hollow wall construction 7mm front (courtesty tomsn16) 5mm rear
net change in front bar strength from 2mm increase in wall thickness
+17% (courtesty of tomsn16)

 

Depending upon where the sway bar attaches [the end link coupling ratio] to the suspension arm you must divide the bar stiffness by a factor of 4-6 to get the actual number of pounds per inch of roll resistance to the wheel tire road interface.

Oem cars [generic] have <200 lb/in springs and < 100 lb/in bars [front might be 200 and rear 70] as measure from the tire road interface.

A neutral car will have the roll stiffness ratio equal to the as loaded front rear weight ratio. With the front stiffer by an extra 5%-15% to induce safe understeer is the norm..........after market bars are designed to reduce this safety margin by stifening the rear stiffness..............since the rear bar is [creates half or less than half of the total rear stiffness to get a 15% understeer to neutral you may need a 30% stiffer rear bar [depending on where the factory started.............a 22% stiffer [common] rear bar is a good place to start.

If you stiffen the front bar you must stiffen the rear bar by the % of the front increase plus the weight ratio plus the understeer ratio.

The problem with stiff sway bars is the oem shocks were not designed to control the extra spring like stiffness in a rapid transition road course.......why they make adjustable shocks to dampen the extra rebound forces. Just like the mild lowering springs are only 15-20% stiffer [at the tire] the mildest setting in the rear sway bar won't over stress the shocks significantly.

 

How does the Tanabe Sways compare to OEM ??

 

Guys...very good info...thanks!

 

Anyone know if g37 rear sway bar will fit g35? Have motordyne exhaust for a 37 trying to make it work for my 35. Thanks!

 

The exhaust, any decent exhaust shop should be able to make fit for 100 or so. IDK about the bar but it probably will hit the exhaust or something.

 

If you're looking to upgrade your sway bars start with the end links and install a set of Power Grid adjustable end links, they will make as much a difference as new sways!
Gary