Downsides to upgraded swaybar?

[Cavpilot2k]

Seeking advice if suspension gurus.
Are there any downsides?
I have an M-sport 135. I am upgrading my suspension (BMW perf. springs and Koni yellows plus M3 front control arms). I am planning to go with the M3 swaybar too, but I read somewhere that it can reduce daily driving friendliness (my car is my DD) on rough roads by eliminating flex in the front end. So when you hit a pothole, rather than one wheel dipping in, the whole front end tilts. This may be an exaggeration, but in theory it makes sense.
For anDD street-only car, does upgrading the swaybar make sense?

[NonoxX]

I have a 135i coupe, with ST XTA coilovers, M3 front / rear suspension arms, powerflex black silentblocks overall and M3 swaybars.
I drive my car daily, and race it a few times a year, but not often.
I must say it makes the car less comfortable, for sure. A harsher chassis makes speed bumps and potholes really uncomfortable. But, I have no regret, as it's just pure fun as soon as curves approach. it all depends on what you're looking for. For me it makes sense and I won't come back on it.

Before upgrading I wondered if it would be too uncomfortable as well. I decided to get used swaybars in a scrapyard nearby for a good price, and if I found it un bearable, I would have gone back to stock and sold them for the same price (it's fairly easy to sell).

[BimmerAg]

I have a H&R solid 27mm front sway bar and I'll say that I haven't really noticed a big difference in ride comfort compared to stock. During daily driving, I will say that the front end feels more solid and planted, and that the reduced body roll is nice.

On track, however, I think this bar may be a little too stiff. During the autocross and track events I've done since swapping the bar, I've definitely noticed more understeer in some conditions, particularly during corner exit. Even in a slowish 2nd-gear corner, I can be full throttle on the exit and the front end will start to push wide before the rear loses traction. Of course, that may be compensated for with the reduced roll, and hopefully slightly more front end grip through the middle of the corner, but I haven't been able to have a good test day yet to know for sure.

[iminhell1]

On an only DD car I don't see the point in upgrading suspension. If something is broken I can stomach a mild upgrade, but not yellows.
Stock works well enough at speeds well over posted and can get you in enough trouble. No need to push that further on public roads.

If you want something comfortable look into the Koni FSD and a set of Swift springs or BMW performance springs. That is probably as stiff as you'd like if you're worried about the M3 bar.



It might actually be easier this way,
What is it you don't like and want to change?

[Ginger_Extract]

What are you trying to fix by changing bars? Throwing bigger, stiffer parts at the car doesn't automatically make it better.

[Cavpilot2k]

Originally Posted by iminhell1

On an only DD car I don't see the point in upgrading suspension. If something is broken I can stomach a mild upgrade, but not yellows.
Stock works well enough at speeds well over posted and can get you in enough trouble. No need to push that further on public roads.

If you want something comfortable look into the Koni FSD and a set of Swift springs or BMW performance springs. That is probably as stiff as you'd like if you're worried about the M3 bar.



It might actually be easier this way,
What is it you don't like and want to change?

I am looking for less body roll and just a generally more stable ride. I don't think the stock suspension is all that well sorted out (though the N55 years had a better stock setup than the N54 years).
The Whiteline inserts have been great, and I think the suspension is crap without them. With them it's livable, but I'd like flatter turns and a generally more stable suspension.
But I still want to maintain good road manners, as this is a DD and in New England we have lots of potholes.
The BMW perf springs are about as aggressive as I want to go spring-wise.
I was planning the BMW perf. Suspension but it is no longer available.
So, I am looking to the Koni yellows because I can put them on a moderate-soft setting to hopefully get the best of both worlds.
The reason I am considering adding the swaybar is again, to control roll in turns and because the BMW PS upgraded to a stiffer bar too and I am trying to mimic that setup as closely as possible.
I want a suspension more like the M2 I just drove and almost bought. It was more supportive in high speed turns and fast direction changes, but still mild-mannered (to me) on the road.

Does that clear things up?

[Dackelone]

I don't like the ride on rough roads with bigger sway bars. At least not in past car's I have owned. I much prefer to go with mildly lowered springs with good shocks. The lowering spring will also reduce sway in a turn or on turn in... but you still have a good ride on rough surfaces or speed bumps.

Dackel

[John_01]

I have the larger E93 M3 front sway bar with performance springs and Koni yellow shocks. I believe there is a slight loss of ride quality due to the E93 M3 front sway bar. That lateral rocking is only noticeable to me on bad roads at lower speed. If you are choosing it for 100% on-road use, the E92 M3 bar should be fine.

[gjm120]

Originally Posted by Cavpilot2k

I am looking for less body roll and just a generally more stable ride. I don't think the stock suspension is all that well sorted out (though the N55 years had a better stock setup than the N54 years).
The Whiteline inserts have been great, and I think the suspension is crap without them. With them it's livable, but I'd like flatter turns and a generally more stable suspension.
But I still want to maintain good road manners, as this is a DD and in New England we have lots of potholes.
The BMW perf springs are about as aggressive as I want to go spring-wise.
I was planning the BMW perf. Suspension but it is no longer available.
So, I am looking to the Koni yellows because I can put them on a moderate-soft setting to hopefully get the best of both worlds.
The reason I am considering adding the swaybar is again, to control roll in turns and because the BMW PS upgraded to a stiffer bar too and I am trying to mimic that setup as closely as possible.
I want a suspension more like the M2 I just drove and almost bought. It was more supportive in high speed turns and fast direction changes, but still mild-mannered (to me) on the road.

Does that clear things up?

What BMWP springs are you being told are correct for your VIN?

[gjm120]

OP - I'd suggest you do the springs, dampers and M front control arms first and see how that feels. (The M arms really improve road feel and turn in.) Then you can consider beefier arb's.

[ShocknAwe]

Have a hr 27mm bar on now with 392# front springs and considering fully removing the front bar to see how it feels and drives. It was nice with lower rate springs but I question if the bar is necessary once front stiffness is already dialed up. Another question is how much negative camber you have up front. I found the bar was useful for under 1.5 degrees, but seems to increase understeer over that. Ymmv.

[iminhell1]

I can't find a number I'd call trustworthy for my spring rates, But the one number I did find was,
148#/in front
456#/in rear
(E90 Eibach Sportline)

I'm on the really oddball suspension. I'm using the Koni FSD pro kit for a E90 on my E82. All the parts physically fit. The problem is the rear didn't come down at all. So I sit wedge. If you're going for aesthetics you won't like it. If you're going for ride quality, you'll like it.
I normally run with the front swaybar disconnected. Yes the car rolls but I don't find that uncomfortable and it does not loose any traction because of it. Body roll is more about driver confidence that it is about grip.

I have a HPDE tomorrow so I put my FSB back in. it adds about 200#/in from what I read. And that's quite apparent right away.





Here is a fair post on different spring rates --> https://www.1addicts.com/forums/show...4&postcount=13
Here is (way too much) info about the stock sway bars --> http://www.1addicts.com/forums/showp...3&postcount=37

[Cavpilot2k]

Originally Posted by gjm120

What BMWP springs are you being told are correct for your VIN?

My supplier hasn't specified yet, but it's 99%likely to come out T2 front/T3 rear just like all the other N55 M-sports with moon roof.

Originally Posted by gjm120

OP - I'd suggest you do the springs, dampers and M front control arms first and see how that feels. (The M arms really improve road feel and turn in.) Then you can consider beefier arb's.

Originally Posted by ShocknAwe

Have a hr 27mm bar on now with 392# front springs and considering fully removing the front bar to see how it feels and drives. It was nice with lower rate springs but I question if the bar is necessary once front stiffness is already dialed up. Another question is how much negative camber you have up front. I found the bar was useful for under 1.5 degrees, but seems to increase understeer over that. Ymmv.

Yeah, now I'm leaning toward just doing the springs, shocks, and FCA's and see how I like that before adding a new bar.

[gjm120]

Other than lifting the car and removing the shielding, I don't think there is any work savings involved in doing it all at once.

If you would, please post what springs you end up with.

[ShocknAwe]

Originally Posted by gjm120

Other than lifting the car and removing the shielding, I don't think there is any work savings involved in doing it all at once.

If you would, please post what springs you end up with.

Front sway bar is probably the easiest part to install on the e82 suspension. Takes time to remove the 20-odd shield screws though.

[gjm120]

Under-body shielding and trunk liner create a lot of swearing on my car.

[ShocknAwe]

Originally Posted by gjm120

Under-body shielding and trunk liner create a lot of swearing on my car.

Oh, the trunk liner can go to fn hell.

[iminhell1]

Originally Posted by ShocknAwe

Oh, the trunk liner can go to fn hell.

The carpet?

that was easy. Just pull the bottoms to the centerline of the car. Comes right out.

[ShocknAwe]

Originally Posted by iminhell1

The carpet?

that was easy. Just pull the bottoms to the centerline of the car. Comes right out.

Mine's warped on the right courtesy of the dealer. Left goes as you say, right needs to be forced into submission.

[Zombie_Head]

The sway bar bushings will effect a lot as well, Polyurethane or rubber and the size as well.

[lowbudgethero]

There have been certain times where I notice understeer in places where I dont think I would expect it, it's easy to control for though. It actually felt perfect with the stock suspension, but once I upgraded the suspension I feel like I should have done the rear bar as well or dialed back the front bar.

I didn't notice any reduction in comfort, but turn in response was improved

[ShocknAwe]

Removed the bar yesterday. So far it's vastly improved. Feels a little disconnected below 25 mph, but at speed its normal. Contact patch is better with only a touch more body roll and chassis flex seems to be better balanced. Haven't really pushed it yet, and I'll put a better write up in my build thread in a couple days.