Sway bars / Arb upgrade

[5harp3y]

Hi all

Has anybody messed around with their Arb / sway bars to alter the handling characteristics of the z3

Mike fishwicks article talks about upping the rear size and you can also take the front down a size too to iron out some understeer

Anyone actually done this?

 

[peteslag]

I've fitted the H & R kit to my Z4 3.0. I was very frustrated at the amount of understeer, it just doesn't seem right in a powerful RWD car. I remember my Z3 3.0 being exactly the same. My initial findings are that is makes the car feel much more agile with no compromise in ride quality. I'm taking it to Cadwell Park in a few weeks time, keep an eye on my progress thread for a full review of how it performs. I'm not after Tokyo drift style cornering, I just hate understeer with a passion. It feels so horrifically safe (aka boring).

 

[5harp3y]

I've fitted the H & R kit to my Z4 3.0. I was very frustrated at the amount of understeer, it just doesn't seem right in a powerful RWD car. I remember my Z3 3.0 being exactly the same. My initial findings are that is makes the car feel much more agile with no compromise in ride quality. I'm taking it to Cadwell Park in a few weeks time, keep an eye on my progress thread for a full review of how it performs. I'm not after Tokyo drift style cornering, I just hate understeer with a passion. It feels so horrifically safe (aka boring).

Thanks for that

i'm the same, the front end of the z3 is not pointy enough for my liking

 

[Ianmc]

I think you will find that the Z3 4 cylinder rack is quickest, certainly noticably quicker than the MC. Understand folks have done this upgrade in the past. Believe that BMW put a "slower" rack in the more powerful cars as a safety measure.

 

[5harp3y]

I think you will find that the Z3 4 cylinder rack is quickest, certainly noticably quicker than the MC. Understand folks have done this upgrade in the past. Believe that BMW put a "slower" rack in the more powerful cars as a safety measure.

The rack is ok for my driving, it is the understeer tendencies that i dont like.

i think i'm going to stay oem but reduce the front ARB size and increase the rear by a couple of mm

 

[NigelM]

I have been looking at this subject and am confused by it. Conventional wisdom says that to reduce understeer you soften the front ARB's and stiffen the rear, which I understand, improving turn in at the front and keeping the rear flatter. However, from everything I have read on here and other sites a great upgrade for the Z3M is to switch the ARB's to H&R, going from 23F/18.5R to 28F/21R which stiffens the front by 21% and the rear by just 13%. This bucks conventional wisdom. Can anyone explain? Is it something to do with body flex or is it just the reduction in overall roll that makes it feel better?

 

[Sean d]

I have also considered upgrading the ARBs, however I don't see any point whatsoever until all the rubber and suspension has been replaced with new, I am on with this now and I'm going to try the car when complete before making any changes to the standard set up, other then some poly bushes

 

[Dino D]

Have you tried getting some camber on the front?
With the BC’s and some camber dialled in it’s not under steery (although maybe I drive it like a granny )
Lowering the front a touch also made a noticeable difference to the feeling of ‘pointiness’ and sharp turn in.

I thought about ARB’s but with some camber and being able to make the front dampers a bit softer compared with the rears I think it would be an overkill for my driving.

If I ever(!) make it to a track day I might feel different but as it is so far can’t complain.

Maybe you do the M3 top mounts mod which give camber I think?

Running a ‘square’ tyre set up makes a good difference too.

 

[Sean d]

I think you will find that the Z3 4 cylinder rack is quickest, certainly noticably quicker than the MC. Understand folks have done this upgrade in the past. Believe that BMW put a "slower" rack in the more powerful cars as a safety measure.

Not quite right and the 1.9 rack could be somewhat slower then other models. Most importantly, the Z3 non-M rack, contrary to popular belief, has the SAME overall travel as the run-of-the-mill E36 rack (146mm). However, it's the only rack in the discussion which is linear rate, which means that it's significantly quicker in the center than the other racks, verified by measurement. This is the steering rack to have: 2.7 turns lock to lock, linear, same travel as the regular E36 rack.

According to RealOEM, all Z3 non-M racks are identical (http://www.realoem.com/bmw/partxref.do?part=32131095575). However, it has been reported first-hand that more than one 1.9 rack has been tried out to have been 3.2 turns lock-to-lock, so try before you buy as RealOEM is not perfect.

 

[Sean d]

Not quite right and the 1.9 rack could be somewhat slower then other models. Most importantly, the Z3 non-M rack, contrary to popular belief, has the SAME overall travel as the run-of-the-mill E36 rack (146mm). However, it's the only rack in the discussion which is linear rate, which means that it's significantly quicker in the center than the other racks, verified by measurement. This is the steering rack to have: 2.7 turns lock to lock, linear, same travel as the regular E36 rack.

According to RealOEM, all Z3 non-M racks are identical (http://www.realoem.com/bmw/partxref.do?part=32131095575). However, it has been reported first-hand that more than one 1.9 rack has been tried out to have been 3.2 turns lock-to-lock, so try before you buy as RealOEM is not perfect.

I got the above off another forum

 

[Brian H]

Changed the ARBs on my Z3 to H&Rs along with poly bushing it did give the car a good feel but the thing that reduced the underwater was camber, I ended up with 2-2.5 degrees in the front and it would turn in beautifully.

 

[peteslag]

I've finally had a chance to give The car a proper test run with the adjustable ARB kit fitted today. It is utterly brilliant. It keeps the car nice and level through the twisties without any compromise of ride quality. MASSIVE improvement over the standard set up. The car behaves like a well balanced agile RWD sports car at last !

 

[Ianmc]

I've finally had a chance to give The car a proper test run with the adjustable ARB kit fitted today. It is utterly brilliant. It keeps the car nice and level through the twisties without any compromise of ride quality. MASSIVE improvement over the standard set up. The car behaves like a well balanced agile RWD sports car at last !

Good result. What make are the ARBs please?

 

[peteslag]

H&R