Guys
I can pick this up for $100 today...should I grab it?

996 GT3 Cup Tubular rear 21MM sway bar w/bushings and links
996 333 701 90 8 position adjustable

The guys selling this has a LOT of GT3 parts for sale and I'll post the link...after I get an answer

 

Buy it! That's dirt cheap especially considering it has the droplinks. You can use it to dial out the understeer.

TDK

 

Waste of $$$$$...........but toss me his phone number ok?

 

yeah yeah...link posted in new thread Ben. Freakin vulture...

My concern is oversteer with the new sway. Could it be dialed out and if so what would the net change be in handling??

 

OEM is around 300 for a rear sway. So that's a good price - and it should fit. That is the same part as the the normal GT3 sway (not specific to a Cup car).

You may also need to upgrade the front sway at the same time, as full soft on the 21mm bar may be too stiff for the smaller OEM front.

Also, rear will simply bolt in - no need for new drop links, but you will definitely need new drop links for the front.

-td

Also here is a good resource for all things racing:
http://forums.rennlist.com/rennforum...splay.php?f=65

 

I think you should be fine..... but search renntech for some tech info. A little oversteer is fun anyway..... I hate under steer which scares the crap outta me.

 

I am currently running only the rear GT3 sway and it's fine with the front OEM bar. The front OEM M30 sport bar is only .5mm thicker than the OEM stock bar The rear GT3 sway has 4 adjustment holes. Unless you are softening the front shocks, stiffening the front springs and stiffening both the rear springs and shocks, then I seriously doubt you are going to create any major understeer issues. Enclosed is the article from the PCNA as a suspension reference http://www.pca.org/panorama/sample_article_3.html

The OEM front sway bar is not small at 23.1mm; the M30 front sway is 23.6mm. I am not sure of the front GT3 dimensions.

TDK

 

GT3 front: 26.7, rear: 20.8
ROW M030: front: 23.6, rear: 19.6
OEM: front: 23.1, rear: 18.5

IIRC, as the stiffness is of the sway bar is increased (i..e, diameter), stiffness increases to the 4th power. So increasing even small amounts has a dramatic affect on stiffness. A .5 mm increase (from stock to ROW) creates a ~10% increase in stiffness. And a 1.1 mm increase creates a ~25% increase. The GT3 increase (rear) is 2.3mm, and (front) is 4.6mm over stock. Front =78% stiffer, and rear= 60% stiffer.

[edit] IMO, running an adjustable stiffer rear bar may dial out the understeer inherent in the 911, bringing it closer to neutral.
When you say that your setup is "fine" are you only driving on the street? Or do you have any track miles on it? Just curious..

If you increase the rear sway and not the front, [edit] this will induce some oversteer. As the 911 is already dialed in with some understeer, this setup may bring the car closer to neutral by removing the understeer.

-td

Proper setup will "allow" this:

 

grab it, it's a good deal

 

My car is a street car not track car. I drive it aggressively, but don't spend my time trying to break it daily. I have the OEM Sport M30/M95 suspension from the 2004 40th Anniversay 996 w/ the Eibach Pro-Kit to drop it 1". USA Sport and ROW Sport cars use the same sway bars; Porsche OEM Sports suspension increases the front sway stiffness by 9.8% and rear sway stiffness by 24.2%. They softened the front shocks by 21% rebound and 13% compression stiffened the rear shocks by 26% in both R/C. They also stiffened both the front and rear springs 17% & 28% respectively. It keeps the car pretty neutral. The Gt3 rear sway with the progressive rate Eibach springs, the 1" drop and the 11" rear rims keep the car pretty flat when cornering. It definitely is not pushing/ understeering harder in the corners.

Again, I am not racing it; If I was, I would be running either the Motons or KWv3, both Gt3 sways, TRG or other adjustable droplinks, Gt3 racing alignment, have the car corner balanced, running on 18's and adjust the bar stiffness and shocks according to the track conditions. There are a million different combinations; some more successful than others.

Unless there are mods to the stock 996 suspension, running both GT3 sway bars alone will definitely induce more underster not less. Increasing the front bar stiffness by 78% and the back just 60% to a car that is already made to understeer will only increase it. The stock car would be better off as is. Stiffer fronts = more understeer, stiffer rears = more oversteer. I do believe the results from the PCA article. This article also has good pointers as well for correcting both under/oversteer. http://www.timskelton.com/lightning/...orrections.htm

TDK

 

Good catch. I completely mispoke earlier, when I stated stiffer rear would not induce oversteer. I had my over/unders backwards. See what I get when I post from work with the boss lurking. lol. I edited my earlier post so that future generations won't be misinformed.

Reducing body roll in the rear (stiffening rear) puts more load on the outside rear tire which tends to induce OVERsteer or dials out UNDERsteer. Softening the front has a similar effect (dials out understeer, or introduces oversteer). Thus, putting on GT3 sways in the rear will create oversteer.

The increase in stiffness is based on diameter alone, disregarding adjustability. Running full soft in front, and full stiff in rear, may be perfect with a stock suspension. But it is likely that it will still push like a piggy.

Now that I've had time to think about it, running the GT3 sway on full stiff with the soft OEM front sway may actually bring the car to neutral.

-td

 

Oh I forgot to mention...

I'm running 225's in the front and 285's in the rear. Sooooooo plug that into the formula...

Tom...correct me if I am wrong that setup creates a little oversteer. I really should have you drive the car and get your opinion. As an added bonus there's beer in the fridge!!

 

just make sure this sway bar is for a GT3 street car which will work vs a GT3 cup car which imho is way overkill. 2cents.

BTW: I have to strongly disagree that a proper handling car should lift it's inside front wheel in the air. In my experience that is plain wrong and just looks neat.

 

With the stock suspension bits and street tires, I don't think this will be much of an issue. On the track, you might get some push. Unfortunately (right now) you can only address this with tire pressure. Maybe jack the rears up 4-5 psi and drop the fronts 2-3 psi. Some of the track gurus will know how to compensate for it. We'll pick their brains next time we're out.

? IIRC, the 6GT3 cup rear sway is the same as the 6GT3 street.

I agree it does look neat. In fact, a stock 911 will do this under the right conditions (e.g., a positive camber uphill turn will lift the inside tire). With upgraded springs/dampers, it may happen more frequently. You will see this in grand am, Koni, and ALMS. It really depends on the car setup and the track. On some courses it is a no-no. On others, it happens a lot.

-td

 

be careful of mismatching front/rear sways... they are optimized as a set. If this was covered already... my bad