What sway bars fit our ti's

[dgroebl]

Please help me understand what sway bars fit on our 318ti's. This is my understanding so far.

SWAY BAR INFO:
Suspension: Front E36, Rear E30/Z3
stock: front 25, rear 14
sport: front 26, rear 16
M Roadster: front 22? do these fit?, rear 18.5
M Coupe: front 22?, rear 19
H&R: front 28(PN: 70970), rear 19(71970) <~$220 bucks each!
E36 M3: front ? do these fit?, rear doesn't fit
E30 M3: front ?, rear ?

My friend once owned a 318ti sport, he complained of too much body roll during sport/autocross driving. So I'm trying to find some thing stiffer than the sport package for as little $'s as possible.

Thanks for your help

[tiFreak]

E36 M3s used a different sway bar that was tied to the struts, so you'd need M3 struts to run them

I've also heard people say that the stock sport bar in the rear is just fine if you have a thicker bar in the front

[dgroebl]

Thanks Pauly! Yeah I don't think I'm going to switch to M3 struts unless I win the lottery and can afford to build a 6 cylinder powered ti, but that's really good to know.

I've heard lots of people on this forum who are very afraid of running running stiff rear bars for fear of the dreaded oversteer! Personally like to think of oversteer as the goal of every good corner, but that's just me.

[Mallard]

you can use the front sway bar from an 6cyl e36 at 25,5mm ( thats 2mm thicker)

the E36 M3 items are actually thinner at 23mm

The e30 M front sways wont fit

--

The Z3 m rear bar (18.5mm) does fit with the correct links

The E30 m3 rear bar is only 14.5mm , and no confirmation on fitment.. but i think it would


All details are given from European vehicle specs, i have not considered the US / pacifics in the search

[dgroebl]

Thanks Mallard,

Do you know, do the front bars from the Z3 or M Roaster fit the front of a ti?

[Mallard]

Yeah they do , and are the same size as the e36 items up to 3.0l

the M versions run a thinner sway just like the E36 counterparts

Weird..

[dgroebl]

yeah it must have something to do with reducing the weight of the bars for the M cars. They'd probably be a lot heaver if they attached the same way as the regular E36, and sense the M cars were probably already using a stronger/more expensive front strut they could take advantage of it by using a lighter design for the bar. Or at least that's my theory.

Now does anyone know of a good listing of OE sway bars sizes for US spec cars?

[Mallard]

try in on www.bmwfans.info for help there

The material is the same i think , bu´t the susp. geometry and dampers are different, so there isnt such a strong dependance for the thicker bar?

i honestly have no idea Lol!!

[tiFreak]

the M sway bars are shorter, so even though they're thinner, they're stiffer

[dgroebl]

Originally Posted by Mallard

try in on www.bmwfans.info for help

wow what an awesome site! Thanks for the tip!

[Bluebimma]

Originally Posted by tiFreak

the M sway bars are shorter, so even though they're thinner, they're stiffer

Yup, its due to their design with their endlinks and suspension geometry as a whole. Its a stiffer setup while using a thinner bar. You can get the tabs to weld onto non-m struts as well as endlinks to attach an M sway to a non-m strut.

[dgroebl]

So I did some research on the BMWfans web site and made this matrix up I hope helpful to someone.

[spidertri]

If you read through the Eibach front sway group buy thread there is some pretty good discussion as to why the ti doesn't need a larger rear sway. I read that some of the guys who autox/track their M coupes disconnect their rear sway bars all together. To control body roll just get stiffer rear springs.

[dgroebl]

Hummmm... well I'll have to read that but as far as my understanding goes, bars transfer grip to the opposite side of the car. So for an autocrossing application i can't imagine why lots of front grip wouldn't be good. I can understand that people would be afraid of a vehicles tendency to overseer, especially on the street, but with as little power as a TI with a worn clutch has it sounds like exactly what it needs to me. But I will read

[gimp]

Bar doesn't transfer grip. A bar steals spring rate from the opposite wheel. So the outside wheel in a turn steals spring rate from the inside.

That being said, a HUGE front sway works well on the BMWs because it limits the amount of roll, and therefore camber change in the front. This actually means that a big front bar will actually increase oversteer, which is counter intuitive.

Removing the rear sway (with the proper rear spring rate) will prevent this "stealing" of rates, and therefore allow better articulation of the rear suspension and improve contact patch. In other works, when that outside wheel steals rate from the inside, it can (and will) lift that inside tire. If you are like most ti's, and lack a limited slip, this means you get "one-tire-fire" as the inside tire becomes unloaded. Upping the spring rate fixes the body roll caused by removing the rear bar and keeps the rotation the way you want it.