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Letís talk Front and Rear Sway Bars

Old 01-06-2019, 01:19 PM
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Gbos1
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Default Letís talk Front and Rear Sway Bars

Hi Guys looking for some opinions / recommendations in regards to Front and Rear Sway Bars for my C4S. Currently mine are stock. Not tracking my car but want to stiffen it up. Thanks
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Old 01-06-2019, 01:35 PM
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Edward
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The stock Porsche bars from the M030 sport package are perfect, IMHO, for stiffening up cornering for daily street use. It is a noticeable improvement but doesn't make the ride feel harsh or jarring in any way. It's an excellent compromise of better roll stiffness and sporty yet comfortable handling. Moreover, it is an easy bolt on item, uses stock Porsche parts, and are not only cheaper than aftermarket adjustable bars but super cheap if you find a set used, which do pop up fairly regularly.

That said, if you're looking for even more neutral handling (more rear-roll stiffness), go with the RoW rear TT bar: it is 21mm instead of the M030 20mm. The fronts are the same 22mm, so US M030 is no different from the RoW, btw. The rear RoW TT bar is harder to find, but offers another increment in reducing understeer, especially with an "S" and its wider rubber in the back that increases understeer. Not a big difference to many who simply want to enjoy their 993's better cornering as the M030 will certainly deliver. But for others, it is another increment of goodness, especially for those who track or AX and can discern smaller differences. Just a data point, mind you, as the factory M030 with good shocks/springs is a fabulous street setup, IMHO. FWIW, my 993 is a daily driver and it feels solid and connected in corners while remaining utterly comfortable for daily use as well as the occasional weekend --or weeklong-- jaunt!

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Old 01-06-2019, 01:39 PM
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IainM
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bigger sway bars will stiffen up the suspension but will also affect understeer/oversteer balance and NVH..
Im on PSS10s in my C2 and found going up one size on the RSB (20mm) while staying stock on the front (21mm) really helped get the car neutral.
But it'll be different for you in a 4S.
Can I ask why you want it stiffer? Stiffening up with sway bars really degrades the ride because potholes on either wheel gets transmitted to both wheels.
I've been told you should set stiffness with springs and then tune the over/understeer with sway bars. Would also like to learn more...
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Old 01-06-2019, 02:02 PM
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911-TOUR
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I went M030 up front and TT in rear when I refreshed the suspension from stock in my 993 - which is now with Tom. The car can be balanced very nicely neutral with that setup. Also be sure you have a front strut bar if you stiffen the anti-roll bars.

Hope that helps!
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Old 01-06-2019, 03:04 PM
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Tlaloc75
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I started with M030, which I really liked, and am now experimenting with the RS bars. So far, with bars set on middle hole, I find them marginally stiffer which has resulted in flatter cornering, a little more steering precision, a bit more grip. The ride is also a bit firmer.

I’m going to experiment with different settings once the roads are dry again, which is the beauty of the adjustable bars. I can tune them to my preference. I can imagine one PSS10/RS-Bar setting for spirited driving and another for cruising and yet another for track work (if I ever get back to the track).
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Old 01-06-2019, 04:14 PM
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OverBoosted28
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Stiffer sway bars do not necessarily impose harshness. Reducing roll, without increasing spring/corner tension, does not immediately impose jarring. The jarring results from poor roads, that’s it. When the suspension tries to either droop, or absorb any abrupt changes in surface, the stiffer bars reduce travel. Combine more corner tension, along with lessened roll, and traveling on poorly constructed/maintained roads is not fun at all. I just avoid poor roads. :-)
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Old 01-06-2019, 07:01 PM
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Gbos1
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Thanks guys for all the input! All these suggestions are great! Much for me to consider here already …………….
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Old 01-07-2019, 01:31 PM
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cgfen
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I typically shop for ANTI sway bars, and when I bought some for the 993, was very happy with the RS adjustable anti sway bars.


Have fun.

Craig
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Old 01-07-2019, 01:33 PM
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cgfen
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Originally Posted by OverBoosted28 View Post
Stiffer sway bars do not necessarily impose harshness. Reducing roll, without increasing spring/corner tension, does not immediately impose jarring. The jarring results from poor roads, thatís it. When the suspension tries to either droop, or absorb any abrupt changes in surface, the stiffer bars reduce travel. Combine more corner tension, along with lessened roll, and traveling on poorly constructed/maintained roads is not fun at all. I just avoid poor roads. :-)
I definitely found my car to be leas compliant when I increased the roll stiffness with the ARBs
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Old 01-07-2019, 02:04 PM
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Steve Weiner-Rennsport Systems
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The only bars we use here are the factory RS ones since this is the prime tool for adjusting the understeer/oversteer balance of the car.

These are 25mm & 20mm bars, respectively and ride quality is not adversely affected, IMHO. Shocks make a bigger difference.

Naturally, your settings will affect the stiffness.
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Old 01-07-2019, 02:05 PM
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TheOtherEric
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Just keep in mind that with bigger sways comes worse ride quality. They go hand in hand, and proportionately. So don't go overboard. Running slightly stiffer in the rear (if you even bother at all) and leaving the front is the best solution for a street car.

I ran TRG and they were even too stiff for the track. I'm not the only one who's said that either. (I now use RS sway bars)

Originally Posted by OverBoosted28 View Post
Stiffer sway bars do not necessarily impose harshness. Reducing roll, without increasing spring/corner tension, does not immediately impose jarring. The jarring results from poor roads, that’s it. When the suspension tries to either droop, or absorb any abrupt changes in surface, the stiffer bars reduce travel. Combine more corner tension, along with lessened roll, and traveling on poorly constructed/maintained roads is not fun at all. I just avoid poor roads. :-)
While this may be theoretically true, we drive on imperfect roads, so bigger sway bars = worse ride quality.
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Old 01-07-2019, 02:12 PM
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TheOtherEric
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Originally Posted by Steve Weiner-Rennsport Systems View Post
The only bars we use here are the factory RS ones since this is the prime tool for adjusting the understeer/oversteer balance of the car.

These are 25mm 23mm & 20mm bars, respectively and ride quality is not adversely affected, IMHO. Shocks make a bigger difference.

Naturally, your settings will affect the stiffness.
A minor typo there. RS bars are 23mm front.
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Old 01-07-2019, 02:53 PM
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Kika
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Here is a good reference: https://rennlist.com/forums/993-foru...r-summary.html

I am using the RoW Turbo (22mm Front/21mm Rear combo) with M030 Springs and Bilstein HD shocks, MY02 wheels and PS2 tires. it is not too harsh, and even my wife finds the ride quality acceptable.
I would recommend you find rennlisters nearby with different combinations, and drive their cars to see how you like/dislike it.
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Old 01-07-2019, 04:31 PM
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Kiwi01
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I have a 95 C2 so it isn't "apples to apples" ... I went with M030 front (22mm) and RS rear (adjustable and 20 mm) using PSS10's. The car sits on 18's with Micheline Super Sports and is about 5mm above RS ride height. I did this work about 5 years ago with Chris Cervelli in order to allow some adjustability for the understeer/oversteer balance of the car. It certainly has helped and did not change the ride quality much. I am very happy with this setup and it certainly gives me plenty adjustability as I work to improve my driving skills. Full disclosure, riding on 18's and this setup is not a "soft" ride, but I find it not too harsh. I hope this helps.
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Old 01-07-2019, 09:28 PM
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Gbos1
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Thanks for all the replies! Great info as always!
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