Installed OEM e93 front sway bar (28mm)

[bluecarbon]

I just ordered my m3 bits from HPA Harold can help you with the e93 sway, I ordered didnt think about the e93 and he emailed me asking if that was what I had intended to order. Install is wed during a 2nd HPFP replacement hopefully this will be the last time for that

[Beerchan]

Originally Posted by AussieRacer

That sounds like a case of too stiff front bar for stock suspension

My impression too, so I'm going to continue with the suspension upgrades. I was fooling myself, thinking I would stop at just the sway bar. I'm still looking for a full review of the the KW Street Comforts somewhere. I've only found a smattering of post here and on e90post, nothing comprehensive, everyone seems to have V1's or V2's. I leaning toward the KW's because I don't think the BMW PS will be quite stiff enough, and I like the idea of some adjustability.

[arrutled]

Originally Posted by Beerchan

I installed the M3 e93 bar a week ago and I can say it definitely makes a noticeable difference. The front feels much flatter during moderate speed cornering and even at highway speeds, I notice less body roll and I get a sense that I have to steer a bit less to go through curves. The downside is that it really doesn't add any extra sense of 'grip' and I notice the soft springs/dampers even more than before. Making quick transitions is actually a bit unnerving. The springs compress, but then the stiffer bar seems to 'catch' the roll and stop it, but the whole experience doesn't feel balanced. I guess that is the issue in a nutshell, adding the stiffer bar has unbalanced the ride slightly. Which means... more mods. So much for the bank account. I'm thinking BMW PS or maybe KW Street Comforts. Anyone want to chime in about the latter? Everyone seems to go for the V1 or V2's but the Street Comforts actually have stiffer springs than the V2's and they are linear, rather than progressive, so the handling should be more predictable. I even read a post where the much vaunted Orb said this was the best out of the box setup for KW's.

Doesnt make sense to me. sounds to me like bushing deflection. The bar is really shifting weight and really can only come on transitionally (more weight from roll = more torque on the bar), its not like an on/off.

[Beerchan]

Originally Posted by arrutled

Doesnt make sense to me. sounds to me like bushing deflection. The bar is really shifting weight and really can only come on transitionally (more weight from roll = more torque on the bar), its not like an on/off.

I'm probably not describing the feeling very well, so please take my opinion with a grain of salt (and a nice beer). I'm not a professional, nor do I play one on TV. Some might even call me a hack, I would agree with them. I'm a nice hack, but a hack none the less.

Yes, it is not truly and on/off feeling, but for me, the stiffer bar has made the softer springs/dampers that much more noticeable, especially when doing quick transitions at highway speeds. I'm not saying it has made the springs/dampers any softer either objectively or subjectively, just that I notice their over compliance more. Sort of like turning down the radio and hearing the road noise. The noise was always there, but now you notice it more.

I'm probably rationalizing the purchase of further upgrades as well.

Don't follow me, for my path only leads to heartbreak, misery and a smaller back account.

[bradford]

Bottom line is you're going to notice ill effects with ARBs that are oversized for the springs and shocks that they accompany. I don't know why this is a surprise...

Don't you think car manufacturers would simply equip cars with fatter ARBs if this was the magic solution? What do you think costs more to make, a hollow tube of metal or a quality, matched spring and shock system? Why do you think car manufacturers went to independent suspensions from live axles decades ago?

A vehicle's suspension is a very sophisticated *SYSTEM* that cannot be instantly cured by tossing a single part at it. You can throw a big fat front bar on the car and get less perceived body roll and sharper turn-in but you still have an underdamped car with terminal understeer. You can't polish a turd.

Too many people looking for free lunch and not enough people interested in getting a decent meal at a reasonable price.

My $0.02, but if you want to make it easy on yourself from a value standpoint, when it comes to suspension/chassis, this should be your priority:

1. Camber plates
2. *MATCHED* set of ARBs & rear subframe bushings
3. *MATCHED* spring and shock set or coilovers
4. M3 links

[arrutled]

Originally Posted by Beerchan

I'm probably not describing the feeling very well, so please take my opinion with a grain of salt (and a nice beer). I'm not a professional, nor do I play one on TV. Some might even call me a hack, I would agree with them. I'm a nice hack, but a hack none the less.

Yes, it is not truly and on/off feeling, but for me, the stiffer bar has made the softer springs/dampers that much more noticeable, especially when doing quick transitions at highway speeds. I'm not saying it has made the springs/dampers any softer either objectively or subjectively, just that I notice their over compliance more. Sort of like turning down the radio and hearing the road noise. The noise was always there, but now you notice it more.

I'm probably rationalizing the purchase of further upgrades as well.

Don't follow me, for my path only leads to heartbreak, misery and a smaller back account.

Ah, I see. Well freakin put.

[arrutled]

Originally Posted by bradford

Bottom line is you're going to notice ill effects with ARBs that are oversized for the springs and shocks that they accompany. I don't know why this is a surprise...

Don't you think car manufacturers would simply equip cars with fatter ARBs if this was the magic solution? What do you think costs more to make, a hollow tube of metal or a quality, matched spring and shock system? Why do you think car manufacturers went to independent suspensions from live axles decades ago?

A vehicle's suspension is a very sophisticated *SYSTEM* that cannot be instantly cured by tossing a single part at it. You can throw a big fat front bar on the car and get less perceived body roll and sharper turn-in but you still have an underdamped car with terminal understeer. You can't polish a turd.

Too many people looking for free lunch and not enough people interested in getting a decent meal at a reasonable price.

My $0.02, but if you want to make it easy on yourself from a value standpoint, when it comes to suspension/chassis, this should be your priority:

1. Camber plates
2. *MATCHED* set of ARBs & rear subframe bushings
3. *MATCHED* spring and shock set or coilovers
4. M3 links

I think they put soft springs on for the ride quality. Put a kink in the M3 bar to improve ride quality and increase body roll to create a very safe understeering car. This car is built for the masses, not us.

FYI, mythbusters found that in fact you can polish a turd, especially from animals on a very high protein diet.

[bradford]

Originally Posted by arrutled

I think they put soft springs on for the ride quality. Put a kink in the M3 bar to improve ride quality and increase body roll to create a very safe understeering car.

Except stiffening a front bar without doing so in the rear as well creates MORE understeer, not less.

[AussieRacer]

Not necessarily.....depends why the understeer is being caused with the stock bar. If it is because the outside tire is being overwhelmed by vertical loads (meaning too much weight on it), then a stiffer bar will reduce this. If the whole front end is losing grip via geometry or just cornering too fast, a stiffer bar may not necessarily cause 'more' understeer, but rather speed up the on set of/transition to understeer.

[adrean8j]

I can confirm that the stiffer front bar does help with the understeer in moderate to sweeping corners at the track...a combination of the stiffer front sway and decent tires makes the understeer a bit more manageable with good throttle inputs. At Roebling Road this weekend understeer only reared its ugly head after about 5-6 blazing laps and heated run-flat tires.....was still faster than most of my group though....

[arrutled]

i suggest looking up the motor trend video on youtube which has randy pobst driving the 135 and states this car great initial turn in followed by so much body roll that the car understeers. The tires are rolling over into positive camber and losing so much grip that the car understeers. In theory though larger bars make understeer, but in practicality the stiffer bars should help with understeer up to a point. I know it helped me, especially in slaloms.

[bradford]

IMHO it's a bandaid "fix".

I can see why people would want to believe that they can spend just a couple hundred bucks to correct the handling on a $40k car, but it's not the correct way to do it. $.02

YMMV.

[adrean8j]

Originally Posted by bradford

IMHO it's a bandaid "fix".

I can see why people would want to believe that they can spend just a couple hundred bucks to correct the handling on a $40k car, but it's not the correct way to do it. $.02

YMMV.

Not a couple hundred bucks.....the swaybar DOES take away a good portion of the initial body roll...especially in everyday driving. There WILL still be body roll at a typical AutoX course...on a road course with moderate to long sweeping turns it is not so evident. I say this with a Hotchkis frontsway and KW V1's......

[arrutled]

Originally Posted by bradford

IMHO it's a bandaid "fix".

I can see why people would want to believe that they can spend just a couple hundred bucks to correct the handling on a $40k car, but it's not the correct way to do it. $.02

YMMV.

yes the correct way to fix body roll would be to increase spring rate and get a good shock to match. But, without sacrificing ride quality the sway bar does prevent the rolling into positive camber on the tires which is where most of this cars understeer comes from. The sway also puts more weight on the inside rear wheel (a bonus). is it technically perfectly mated? no. I doubt you could find anyone on here who has upgraded their sway bar and got slower lap times at autocross or the track. You know what I mean? just cause its cheap doesn't mean it does not work.

[Beerchan]

I don't think anyone here, including myself, was fooling themselves into thinking that this was going to cure everything. The fact that it is just so cheap and easy to install, makes it too tempting not to try it out. Yes, I know it is supposed to be one of the last things you do, but did I mention "cheap and easy?" I so love cheap, and when it is paired with easy, I just can't help myself.

I agree with Arrutled too, the suspension was purposely made soft and not to save BMW any money, but to appeal to the masses, make the car 'safer', and cover up for the RTFs. Look at the much maligned rear sub-frame bushings. How much could BMW have possibly saved when building the car using the mushy ones we have? 50 bucks, if anything? If they had installed good ones, we'd all be a lot happier. I would have done those first, a set of new sub frame bushings is not much more than a good sway. However, the easy part was missing from the equation and I'm just a hack and would likely drop the drive shaft on my head. Being very attached to having my brains stay inside my skull, I'll have to get a professional to do the work, factoring out cheap from the equation.

Back to the thread topic, I don't notice any additional understeer at speed, and at moderate speeds I feel there is a decent amount less.

[philiopf22]

this has been an informative thread. I'm curious if there exists a compiled list of "best practices" around upgrading suspension. Obviously this caught my eye, as well as some of the bushing threads. I know it recommendations will vary depending on the type of driving you do but I'd be interested to see what was out there.

[TimMc]

Yes, very informative. I'm attracted to the quick fix that a larger front sway gives but have some reservations.
1. As highlighted above, I believed that either a smaller front bar or bigger rear bar was needed to dial out understeer. I see AussieRacer's argument though.
2. If the above is true, putting a bigger rear bar on may help make the car more balanced, but will adversely affect traction from our non LSD equipped cars. As pointed out earlier, it will then lift an inside rear wheel more easily through corners.
3. If just changeing the front bar alone, would it be a better compromise to fit an E92 M3 bar rather than the larger E93 bar?
Cheers, Tim.

[AussieRacer]

Originally Posted by arrutled

yes the correct way to fix body roll would be to increase spring rate and get a good shock to match.

I wouldn't say correct, I would just say it would be one way of fixing problem. Correct way (if due to too much weight transfer onto outer front - which I believe is the cause), would be to have the weight transferred more to the rear. Of course there are many ways of doing this. Your suggestion is one way of doing that.

[arrutled]

Originally Posted by AussieRacer

I wouldn't say correct, I would just say it would be one way of fixing problem. Correct way (if due to too much weight transfer onto outer front - which I believe is the cause), would be to have the weight transferred more to the rear. Of course there are many ways of doing this. Your suggestion is one way of doing that.

agree 100%. what suspension you got going on?

[arrutled]

Originally Posted by Beerchan

I don't think anyone here, including myself, was fooling themselves into thinking that this was going to cure everything. The fact that it is just so cheap and easy to install, makes it too tempting not to try it out. Yes, I know it is supposed to be one of the last things you do, but did I mention "cheap and easy?" I so love cheap, and when it is paired with easy, I just can't help myself.

I agree with Arrutled too, the suspension was purposely made soft and not to save BMW any money, but to appeal to the masses, make the car 'safer', and cover up for the RTFs. Look at the much maligned rear sub-frame bushings. How much could BMW have possibly saved when building the car using the mushy ones we have? 50 bucks, if anything? If they had installed good ones, we'd all be a lot happier. I would have done those first, a set of new sub frame bushings is not much more than a good sway. However, the easy part was missing from the equation and I'm just a hack and would likely drop the drive shaft on my head. Being very attached to having my brains stay inside my skull, I'll have to get a professional to do the work, factoring out cheap from the equation.

Back to the thread topic, I don't notice any additional understeer at speed, and at moderate speeds I feel there is a decent amount less.

I am a hack in training by the way, lol. I think if you wanted to completely rid of understeer the quickest way to do it is to add some camber in combo with the sway bar. if you havent measured your camber yet, you prob have a big fat goose egg. In my mind you are trying to control your body roll so that you increase your contact patch. so if you still got body roll and 0 camber, your not helping yourself. thoughts?

BTW, I am very much enjoying this discussion. Lets keep it going.

[bmw13]

whats the verdict, can someone skim the fat for us?

[arrutled]

you need to explain your goals first before anyone can help you. daily driver? autocross? track? Amateur? expert? My suggestion is to call TC kline or HP autowerks, because they are actual suspension tuners.