Sway bars

My son just replaced the sway bars in his 01 Miata SE with some better ones. I swear the one that came off in the rear was the thickness of a pencil. Anyhow, I thought it was a dumb idea at first, you can definitely feel the difference. My question, would it be noticeable on a 996 4S? I�m always looking for ways to make the car feel a little less luxury and more sporty. I already have h&r springs and bilstein b8�s. Thanks, David

I put an Eibach adjustable sway bar on the back of my 996. It significantly reduced the understeer on turn-in. The Eibach bar was less than $200 at FCP Euro and is the same as the H&R adjustable sway bar for about 1/2 the price. While I would have preferred a GT3 sway bar clone, I am satisfied with this one. Sway bar fundamentals: rear sway bar changes front wheel dynamics, front sway bar changes rear wheel dynamics. Stiffen rear sway = decrease understeer. Counterintuitive I know.

Argeo, do you mind sending a picture on how you 4S sits with the H&R springs and b8's and provide feedback on the ride compared to stock? I have a 4S and the front just sits too high compared to the rear. Im ok with the ride but have heard somone commenting there was too much roll with their H&R springs. I think this was for track use which i dont plan to do so am more interested in the differences in ride from stock and stance. Thanks, Stephen

If u get the gt3 style bars that have multiple attachmemt points u will need adjustable sway bar links.

One thing I didn�t realize was the tire walls are small on rear than front. To me it looks a little like car is squatting.

Now full disclosure, I am not joe race guy. Would I notice different sway bars at legal speeds?

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You will notice them, but that doesn't mean they will improve anything. The engineers at Porsche weren't stupid you know... Likewise the pencil bar on the Miata is the correct bar without further supporting mods.

I am aware they are not stupid but I am also aware they don�t do things because of regulation, cost, other�

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Not quite true. The Porsche engineers are not stupid. But, they designed the exact car they were given specs for. The C2 was delivered to us in the US as a comfy sport cruiser for the rich folks who wanted more Porsche cache than a Boxster. Plush suspension and a somewhat behaved manner were what the marketing department wanted to sell. Even the M030 was wimpier than the RoW M030. The 996 C2 was engineered with understeer to keep the rear from stepping out. The company needed the car to sell enough here to save the 911 line. When a more rigid sway is put on the back, that understeer is dialed out and the nose tracks more neutral under braking and acceleration. Rear squat is reduced so the front keeps more weight on the wheels when the fast pedal is pressed. So just a rear sway improvement is the best and cheapest way (short of high octane fuel) to make a performance improvement on the 996 C2/C4. Nothing else needs to be added and the swap takes about 30 minutes.

Another thing is that u have a 4s. Your bars r bigger then a standard c2. An aftermarket bar will still be stiffer but it will be less of a jump then from a c2 bar. There r some used h and r bars in the marketplace, maybe they r worth a try?

The stock C4S rear sway is 21.7mm and Eibach rear is 24mm. C2 rear sway is 18.7mm stock/19.6mm M030 and Eibach rear is 22mm, as examples.

Do all 996 sway bars fit each type of 996?

I have the Eibach sways front & rear. I had the rear in the middle setting, this induced over steer at high speed sweepers so I put into the softest setting and now feels a lot more balanced with much more rear end grip. But I guess everyones driving style might be different to mine..

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Yes along with boxter bars. I actually ran the 19mm boxter sport bar for a few years.

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Yep. You gotta find a set-up that you are confident with on the track. Get to know it's quirks and then slowly tweak it if needed. Funny how little tweaks can make big differences good or bad on the track. Not funny when it scares the he'll out of you either. 😁

@De Jeeper How was the 19mm bar?

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The front sway bar on the C4, C4s & Turbo are different due to the front axles... they may also be a little thicker/heavier due to the extra weight up front.

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My car (3.4l) with the sport bars front and rear on street tires, lowering struts and some track suspension bits...they were well matched with the set up. Now my car (3.6 gt3 motor), ohlin gt3 r&t and nt-01 tires.... they feel non-existant. I tried to upgrade to a set of adjustable gmg (made by eibach i think) but the rear bar wont work with my motor. Its so bad i bought rennline semi solid motor mounts to help with the rear end whip and understeer. Ill get the rear sway figured out over the winter and im sure the car will be much better.