Rear sway bar... different ones in later cars? And what about the GT4 one?

[driftflo]

hey guys,

i just bought a M3 GT4 rear sway bar, which has a 22mm diameter (and comes from eibach, by the way).
the street cars should have a 20mm one.

when i recently measured the one in my 2012 E92 it was 23mm?!

hmmm... did they change the diameter in later (LCI) models?
if so, is the GT4 one still stiffer due to thicker wall thickness or different material?

or does this mod not make sense in a 2012 M3?

[M3PO]

Measure the diameter of your new 22 mm bar. A thick coating (1.5mm) on a 20 mm nominal thickness bar could make it measure out at 23 mm. If this is true, I would expect your new 22 mm bar to measure ~25 mm.

Originally Posted by driftflo

hey guys,

i just bought a M3 GT4 rear sway bar, which has a 22mm diameter (and comes from eibach, by the way).
the street cars should have a 20mm one.

when i recently measured the one in my 2012 E92 it was 23mm?!

hmmm... did they change the diameter in later (LCI) models?
if so, is the GT4 one still stiffer due to thicker wall thickness or different material?

or does this mod not make sense in a 2012 M3?

[driftflo]

the gt4 is 22.08... the oe is 23.?

[driftflo]

no ideas? no one ever thought about upgrading the rear swaybar?

[italyix]

Originally Posted by driftflo

no ideas? no one ever thought about upgrading the rear swaybar?

I just upgraded both front and rear to RD Sport. Upgrading just one might upset the balance of the vehicle.

[driftflo]

the reason for installing this rear swaybar is actually to modify the balance from understeer to well balanced
as bmw uses the stock front swaybar and only changed the rear one in the gt4, i guess they had the same goal ;-)

[CarbonFoot]

Is the rear bar off the GT4 solid or hollow?

[driftflo]

hollow

[driftflo]

still no one?

[PrimeBMW]

James Clay jump in here if I am wrong.

E46 M3 race cars: It is my understanding that most east coast guys run without a rear sway bar completely. The west coast guys typically run a sway bar that is softer than stock. I just bought a Ground Control rear sway bar with 5 adjustments.......all softer than stock.

[driftflo]

this is definitely the way to go if you are addicted to understeer ;-)

i perfer a loose tail (or at least as few understeering as possible)... so i need a stiffer rear swaybar.
but i don't want to discuss about driving dynamics here. i just want to know the difference between GT4 and LCI swaybars.

[Richard@M-World]

According to BMW's ETK, the rear sway bar is 33552283655 with an outer diameter of 22.5 mm.

Same part number from MY 2008 to 2012.

According to the parts catalog for M3 GT4, the rear sway bar is 33508321821 with an outer diameter of 22.5 mm.

So, given that OD is the same, perhaps the ID and/or shape is different?