E46 sway bar

I have an '01 330ci with the sport package which (I'll assume) has the lowered suspension and other suspension goodies. This car has noticeably more body-roll than my previous '96 328is. Is this normal or is there
something wrong? Is this condition curable with an upgraded (aftermarket) sway bar? If so, which one would you recommend? I would accept a slight decline in ride comfort for a more level car in the corners. TIA for everyone's help.
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Check the diameters of your anti-roll/sway bars against the list below.
** ======================================================= ** Coupe Rear 18mm 33 55 1 095 758 (33 55 1 138 104 x 2pc) Rear M3 21.5 33 55 2 282 181 (31 35 2 229 711 x 2pc)
Front 23.5 31 35 6 757 168 (33 55 6 751 269 x 2pc) Front M3 26mm 31 35 2 229 755 (31 35 2 229 756 x 2pc) ** ====================================================== ** Convertible Rear 18mm 33 55 1 095 758 (33 55 1 138 104 x 2pc) Sporty/MSport 20mm 33 55 6 751 267 (33 55 1 096 669 x 2pc) M3 21.5 33 55 2 282 181 (31 35 2 229 711 x 2pc)
Front 23mm 31 35 1 097 178 (31 35 1 097 179 x 2pc) Sporty/MSport 24mm 33 35 1 094 542 (31 35 1 094 556 x 2pc) M3 27mm 31 35 2 229 485 (31 35 2 229 436 x 2pc)
The first p/n is for the bar, the second is for the rubber mounts. The brackets for the mounts appeared to be the same across different bar sizes. There doesn't appear to be any thing else necessary to swap bar sizes, aside from replacement fasteners if your's are tired.
I don't have first-hand experience with the E46. That said, I expect that you can change the rear bar yourself with simple hand tools. If access to the front bar is similar to my E39, you'll need help.
In checking out bars for my E39, I came across aftermarket selections from Dinan, AC Schnitzer, Racing Dynamics and Eibach. Eibach offered the largest rear bar and the lowest cost for my application. RD is more (but competitive), Dinan expensive and AC is somewhere out in lala-land. (I recognize that the other bars offer rear-adjustability and in at least one case urethane mounts.)
(I found the best prices for Eibach at 'www.ultrarev.com'. 'www.drivewire.com', 'www.import-racer.com' and 'www.drivewerks.com' weren't bad either. I have no prior purchase experience with any of these outfits.)
However, M5 bars are the same size as the Dinan bars, much less money and readily available from my friendly BMW partsman.
In your application, you have four alternate bars to choose from for the front (five in total including the current bar on your car) and two for the rear (three in total).
Keep in mind that if you only change one end of the car, there will be a difference in the balance. Going up in size at the rear only will tend to shift a neutral car toward oversteer. Going up in size at the front shifts balance toward understeer.
Ken R.
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Well almost. Dinan: 28mm fr/17mm rr. M5: 27mm/16.5.
(The inexpensive Eibach's are 28mm/18mm.)
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Planar1 wrote:

the
noticeably
(aftermarket)
It's more curable with aftermarket *springs*. Messing with the antiroll bar is *secondary* in controlling body roll. -- C.R. Krieger (Been there; done that)
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I don't disagree with the remark above, but in a world where aftermarket springs are rated by how much they lower the average car instead of what their spring rate is, this makes changing springs kind of hit or miss when the aim is to reduce body roll.
Alternatively, there are the OEM springs. A little guesswork or judicious investigation will lead to replacements that increase roll stiffness while retaining stock ride height.
Still, in the moonscape that is the road system I drive on, I have no interest in reducing suspension travel or in increasing spring rate. The M Sport configuration on my E39 is about the limit for this environment. For me, stepping up the anti-roll bar size reduces body roll with a negligible increase in overall suspension stiffness. It does not seem like too much of a leap to assume that the same holds true from the guy with the 330Ci Sport.
Ken R.
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