Swaybars vs. Coilovers

[E30nate]

so i am getting my taxes back soon and want to finish my suspension. right now i have bav auto springs and billy sports. im for sure getting all new bushings, but what i would really like some feedback on, is should i get bigger swaybars or do coilovers. my car will mainly be a DD with spirited weekend driving. i know with coilovers the ride will be quite a bit more harsh, but will swaybars help conciderably with the body roll, which is what i want to overcome.

Clifnotes: should i get swaybars or coilovers for a spirited DD car to help with body roll?

[1991 318is]

Get adjustable sway bars.

[PaintPro21]

sway bars would be fine as they won't effect ride quality. but for handling, higher spring rates are the way you're supposed to deal with excessive body roll, not with sways. Since you didn't mention track use or autocross use (doesn't mean you won't go, but your clearly not trying to be competitive) then sways would be fine.

[DSP74]

sway bars would be fine as they won't effect ride quality. but for handling, higher spring rates are the way you're supposed to deal with excessive body roll, not with sways. Since you didn't mention track use or autocross use (doesn't mean you won't go, but your clearly not trying to be competitive) then sways would be fine.

Disagree.

At least to a point

[E30nate]

sway bars would be fine as they won't effect ride quality. but for handling, higher spring rates are the way you're supposed to deal with excessive body roll, not with sways. Since you didn't mention track use or autocross use (doesn't mean you won't go, but your clearly not trying to be competitive) then sways would be fine.

thats what i was thinking. i might do the occasional auto x or track day, but it is mostly a dedicated street car.

[JRKOUPE]

coilovers or sways?.....

geez thats like saying shoes or a suit?........


what do you want to achieve exactly? do you want to play w/ ride hts?.....or sprg rates?


on the contrary, a nice c/o set up can ride very well....

sways traditionally are for reduced roll.....but alot of tuners use hi sprg rates as stated. Get IE sprgs or HR race.....sell your springs....keep stock sways....done. Or...go sways...it sounds like you dont NEED to spend over a grand on c/o's.....

[Bimmerman325i]

Looking at this from a vehicle dynamics viewpoint, there are many advantages and disadvantages to going with sways vs. coilovers.

I would go with sways, and here's why: stiffening the swaybars speeds up dynamic weight transfer from left to right at the expense of less grip on that axle-- less energy is lost in flexing the swaybar. Since the swaybar flexes less, the body rolls less, and the result is that you feel more in control and better able to drive to the limit. The downside of stiffer sways is reduced ultimate grip on those wheels, along with a less compliant suspension(you feel bumps more). The bars do infact increase grip on the other wheels due to weight transfer front to rear-- this is why you buy adjustable sways to tune out over/understeer.

Keep in mind that while a bigger swaybar does reduce roll, if you go too big you start loosing too much grip with a lessening effect on body roll. Just because you can buy the biggest bars really does not mean you should.

I would not put coilovers if your car is mostly used for street use. Not because of the harsh ride and the additional expense, but because a good coilover suspension system will include sways, dampers, and good tires. Ironically, the tires are the most important part of the suspension, not just because they are your four contact patches with the road, but also the internal tire spring rate(sidewall stiffness is a large part) should be taken into account for designing a proper suspension.

That said, the main reason I would not do coils on a mainly streeted car is because even with a higher spring rate, you will not be able to tune for under/oversteer nearly as easily(unless you go with full double adjustable dampers, and even then only to some degree), you will not be able to tune for body roll easily, and you will still have the stock sways in all their glory. Your car will feel stiffer, but will still roll and will not transfer weight quick enough to keep up with the stiffer springs and dampers, and you car will not be as effective and entertaining as if you did sways first, and upgraded to coils later if at all.

You already have good springs and shocks, so add sways and you will be very, very pleased. Coilovers are overkill for your purpose, go for swaybars. Your wallet will thank you.

[DSP74]

Springs stiff enough to reduce body roll to the extent we need would be WAY to stiff without larger bars. And springs that stiff will reduce grip at that end considerably more than a larger sway bar. People like stiff springs because the car feels more go-kart like. But didn't actually gain any grip. And in many cases lost it.....

Coilovers just cut into the already valuable rear tire space..

A swaybar will many times add more grip up front. This being the case even if the car is already understeering.......First place I'd look to reduce understeer on these cars is a larger front bar......

[DSP74]

Your car will feel stiffer, but will still roll and will not transfer weight quick enough to keep up with the stiffer springs and dampers, and you car will not be as effective and entertaining as if you did sways first, and upgraded to coils later if at all.



.

Stiff springs will make the car respond much quicker than a stiffer swaybar.

Beyond that though I just have to ask could you clarify as I'm not making sense of what your trying to say here.

[DSP74]

As some have seen I'm definately not all about stiff springs. UP FRONT.....With the tendancy to lift a REAR wheel as well as front there is no way in hell I'd run anything other than a stock rear anti-roll bar.....Springs are the way to go in back.......But it also means some unique shock work.......Beyond what your typical Koni can do for you.

[erik325i]

First place I'd look to reduce understeer on these cars is a larger front bar......

Excuse me? A larger front bar will promote more understeer.

-Erik

[scabzzzz]

Coilovers with appropriate dampers feel fine on the streets. Just get the coilovers, run a medium drop, and be done. Replace stock sway bar bushings and you will be satisfied.

[DSP74]

Excuse me? A larger front bar will promote more understeer.

-Erik

Wrong.

[rs4pro3]

Larger front bar more understeer, Thinner rear bar more oversteer.
And I'd do springs before sways.

[Massive Lee]

Larger front bar more understeer, Thinner rear bar more oversteer.
And I'd do springs before sways.

Larger rear bar = toward oversteer. :up:

Clifnotes: should i get swaybars or coilovers for a spirited DD car to help with body roll?

Start with stiffer springs. Swaybars are only a spice on the suspension recipe. Rears should be 150% of the front rate.