Running with no rear sway bar: opinions

[Hoffbrohaus]

Was interested to get a little more input on running no rear swaybar. I recently got under the car and saw the rear sway bushings were done and that a PO had put in an original version of the 19mm ST rear sway. The brackets are old and in bad shape.

So I did some research and found a lot of posts about running no rear sway when you have stiffer springs. No one says what is stiff enough, I'm running H&R sports with Koni's. Not tracking the car but do plan on Turbo. So the question is do I put new bushings on the 19mm? go no sway bar? or just put in an oem smaller bar?

[AWDBOB]

moatilliatta likes no rear sway. I also bought a track car from a gentleman who was advised by Will Turner to run no rear sway and up his rear spring rates to accommodate.

Disclaimer- I have no experience and am no expert.

[Panici]

Was interested to get a little more input on running no rear swaybar. I recently got under the car and saw the rear sway bushings were done and that a PO had put in an original version of the 19mm ST rear sway. The brackets are old and in bad shape.

So I did some research and found a lot of posts about running no rear sway when you have stiffer springs. No one says what is stiff enough, I'm running H&R sports with Koni's. Not tracking the car but do plan on Turbo. So the question is do I put new bushings on the 19mm? go no sway bar? or just put in an oem smaller bar?

I wouldn't consider H&R Sport springs stiff at all. That's what I chose on my E30 mostly for ride comfort.
(As an aside, I've been running Billy Sports but am considering upgrading to Koni adjustables which should be a better match).

I'm actually putting in a set of Front & Rear 22mm/19mm bars from ST Suspensions very soon. Going to use some AKG weld-in rear swaybar reinforcements for the chassis-side and have already reinforced the trailing arms. Soft springs (lots of suspension articulation) and stiff bars put a lot of force through the swaybar mounts.


I am a fan of the soft springs/stiff swaybars combo after I set my Miata up that way. People also recommend not running a rear bar on the NA6 chassis.
Ride comfort on the road combined with less body roll and much more controllable weight transfer when changing direction has been my experience.

That said, I prefer a car that oversteers at the limit rather then pushing the front.
Generally at the limit understeer is preferred (safer?) and how nearly all cars are set up from the factory.

From what I've heard, stiffer bars can make you unweight/lift the inside tire and actually slow down your corner speed. I want them mostly to control the body roll that comes with soft springs.
I'm not a racecar driver, just here to have fun.
Even though I do enjoy a track session, I'm not concerned about laptimes. So being "slower" doesn't bother me.

Hoping to have my cake and eat it too with comfort/performance, but we will see how it goes.


Track footage of the miata.
It crosses up if you come into a corner too hot, but then it doesn't have enough power (or an LSD) to hold the slide if I power on.

I know my E30 will kick the back end out under power, so hoping the stiff rear bar makes things even more exciting.

https://www.youtube.com/watch?v=eW_2muIO8TE

[reelizmpro]

"Stiff" typically refers to coil over spring rates of 600lbs/in + so sport springs don't really come close. Also the 2.5" ID race springs are ordered or easily swapped with the desired spring rate anyway so many will just remove the rear bar altogether and have the rear springs do the work. It all comes down to preference. Back in the day, sway bars were an easy way to stiffen up the soft Eibach/H&R sport spring sets that were predominantly available.

[Hoffbrohaus]

Yep found this post from thejlevie "H&R Sport springs have rates of 180lb/in front and 380lb/in rear. H&R Race springs are 315lb/in front and 570lb/in rear." so yea 380 are considerably softer than the race springs at 570.

I'm with Panici, want the comfort and performance for an occasional track day, don't care about lap times. So I'm going to repaint those brackets, get new urethane bushings, and bolt the 19mm control arm back up.

I'm actually putting in a set of Front & Rear 22mm/19mm bars from ST Suspensions very soon. Going to use some AKG weld-in rear swaybar reinforcements for the chassis-side and have reinforced the trailing arms. Soft springs (lots of suspension articulation) and stiff bars put a lot of force through the swaybar mounts.

I'm interested to hear how much it costs to weld in the reinforcements. Also are you dropping the whole subframe for the shop or taking your car in with the drop links disconnected to get them welded on the car?

[jbontke]

I'm interested to hear how much it costs to weld in the reinforcements. Also are you dropping the whole subframe for the shop or taking your car in with the drop links disconnected to get them welded on the car?

You may be able to weld them in with the subframe in the car. I bought a subframe, did the work and swapped it out. I would say if the rear subframe to chassis bushings have not been replaced, look for a used rear subframe and rebuild it.

[Panici]

I'm with Panici, want the comfort and performance for an occasional track day, don't care about lap times. So I'm going to repaint those brackets, get new urethane bushings, and bolt the 19mm control arm back up.

I'm interested to hear how much it costs to weld in the reinforcements. Also are you dropping the whole subframe for the shop or taking your car in with the drop links disconnected to get them welded on the car?

I did all the work myself, so can't comment on cost. I already had the rear subframe out to upgrade so there was lots of space to work.
Went with weld-in reinforcements from AKG Motorsport.

[kronus]

I've spent a lot of time on track both with and without a rear sway bar. My observations are that the car understeers more without the rear sway bar, but it's still possible to get the rear to move around with reasonable application of inputs. I found it easier to catch oversteer without a rear sway. The car was nearly undrivable on track with a rear sway installed, but it was also a pretty weird car and this behavior may have been unique to it. (M30 swap, 25mm front sway, a lot of weight taken out of the rear)

[hoveringuy]

I run moderately stiff coilovers, still soft enough for street use. I've run both no rear bar and a small stock bar and can't tell that much difference, but usually have the bar connected because it's slightly more balanced in the corners.

[Digitalwave]

It depends a lot on the overall setup of the car and how you like the car to drive. For a street car, run whatever, you probably won't notice the difference in most scenarios.