Sway bar choices

#1

Not a Spec series car but thought I’d come here to get some advice.

I have Bilstein Sports on Eibach lowering springs on my 85 325e. I’ve done an “i” swap, and its an early eta car so it has 18.5mm front and 12mm rear sway bars.

The eibach springs are REALLY soft and I thought I’d change sway bars before springs. The later “318is” or “325ic” cars has 21mm front sways and the “ix” cars had 14.5mm rear.

Is this a worthy upgrade to prevent a while lot of lean I am experiencing?

Check out this video to see for yourself (rear Bilsteins were not installed at the time).

Sorry for the LONG intro but go halfway and you’ll see what I mean:

http://www.streetfire.net/video/mosport-may-2010-drivers1_2018776.htm

#2

To be honest, the best bars are the ones from Ireland - Spec E30 does have a non-adjustable set, but Ireland also makes a different adjustable set and a thicker rear bar that would probably suit your needs perfectly.

Personally I found that the car didn’t really work until I added Camber plates, springs, shock, sway bars as a total package.

Also after this was complete I realized to make the car really work properly I need to get a real alignment and replace all the bushings. The rear subframe bushing and the caster bushings should really be a priority.

#3

I’ve replaced all bushings in the entire car. Used M3 offset in the front and stock everything else. Stock rear control arm bushings etc…

I’m not interested in splitting my strut assembly again at the moment otherwise I’d get a set of camber plates.

If this is a track car what size rear or front sway bar worked?

#4

Not sure I get the point about splitting the strut assembly… Camber plate bolt in on top of the strut and purely provide added levels of camber. There’s no splitting required.

You need this:
http://store.nexternal.com/ireland/sway-bar-set-for-e30---25mm22mm-p9.aspx
and this:
http://store.nexternal.com/ireland/camber-plate---adjustable-streettrack-p594.aspx
and this would help a ton:
http://store.nexternal.com/ireland/rear-subframe-mounts---urethane---street-pair-p406.aspx

#5

Stiffer sways will help with body roll, but stiffer springs will make a much bigger difference.

The Eibach Pro-Kit springs are not any stiffer than stock springs, they are just shorter. Eibach Race springs are roughly the same as H&R Sport, which are a good bit softer than H&R Race springs.

#6

You all have given me a lot to think about.

I cringe about dropping the subframe again for the IE bushings. However I see they will make a difference.

Does everybody agree the 25/22mm sway bar is the way to go?

#7

Sway bar choice is directly related to spring rates. 25/22mm sways would be right for high rate coil overs or Turner J stock springs. 22/19mm sways are about right for H&R race or IE S3 springs. Either are way too much for the Eibach springs you have.

#8

PO, suspension is a system. You need to research successful systems and then buy it’s various components. Don’t think of a sway bar as fixing body roll, think of sway bars as stealing traction from the inside tire to compensate for loss of camber in a turn.

The most significant downside of body roll is that it makes the outside tire in a turn roll under. Fighting body roll isn’t much of an objective all by itself, the real objective it so keep that outside tire from tilting beyond neutral.

Springs fight body roll but don’t steel traction.

Additional camber makes it less necessary to fight body roll.

The bottom line is that stiffer sways are not necessarily indicated. The stiffer the sway the more traction you steal. You really all hot to have less traction?

#9

A lot of amazing info specific to my car! Thanks for everybody’s input.

I wouldn’t say I’m struggling for traction actually. The Falken 615Ks seem to perform well. I just watched my video and saw a lot of “roll”. Granted too stiff isn’t great as well.

Perhaps somebody could watch the video (Mosport) and comment on what would be the next appropriate upgrade. The car is neutral right now with no hint of over steer (this might change as I just did a 3.73 from 2.79 swap and M20b25 for my eta engine).