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-   -   RSR Sway Bars (http://forums.pelicanparts.com/porsche-911-technical-forum/697938-rsr-sway-bars.html)

aradsinc 09-01-2012 04:38 PM

Question
How do you install a articulated bolt that connects to the sway bar ?

DG624 09-05-2012 01:13 PM

The difference is that if you have very stiff antiroll bars the car will be less stable over rough surfaces because the antiroll bar transfers load across an axle much quicker than would happen with a normal spring.

For maximum grip, you want to reduce load transfer so that the tires are more evenly loaded. ... This means that any of those three can be used to tune the handling and to reduce roll.

In a transient situation (slalom, turn entry) we are talking about how fast the load transfers rather than the total amount. It is in this situation where the three types of roll resistance differ.
The one that transfers load the fastest is the high roll center. In this, the vertical force on the tire increases or decreases as soon as the tire produces a lateral force. These forces are sent through the suspension linkages themselves and bypass the springs.

Slower than the roll center are the normal springs and the antiroll bar, which both require roll angle (and therefore time) to work. On a smooth track the two are equal, but on a bumpy track the large antiroll bars will be a disadvantage. This is because when one wheel encounters a bump with an antiroll bar, the other wheel very quickly feels a force from the antiroll bar since the two sides are connected with it. With independent springs, however, the other side feels nothing until the chassis is displaced, which takes longer due to the inertia of it.

Therefore, if you can achieve your desired roll couple distribution using only independent springs you should do that.

Winders is correct that one, small (relative to main springs), adjustable antiroll bar is a nice tool to have to fine-tune the handling for different circuits. But you only should need one.



Fliegler I assume you mean you want the suspension to reduce body roll not weight transfer which is constant. If you have stiff springs then what amount of the body roll should the sway bars be reducing? IF I have 21/28mm Tbars then is there a formula or percentage to account for sway bar dia? Assuming a 2500lb car and F/R track that is stock with 7/8 inch wheels then can I calculate the desirable bar rate?

Flieger 09-05-2012 01:19 PM

You are correct that steady-state, total lateral load transfer is constant and depends on track width and cg height.

However, I was speaking about the rate of weight transfer, which can vary quite a lot due to roll center height, spring stiffness, damping ratio, etc.

You want to reuce roll to the point that the static negative camber you run allows the tire to be at its optimal camber in a turn. This will vary between cars and tires. If you have enough camber recovery you don't need static camber and can run the car softer.

In the end it is about lap times. You make some educated guesses at setup then go out an do lap after lap making small changes and seeing what is fastest or feels most drivable.

DG624 09-05-2012 01:57 PM

The car handles fine but there is still some body roll. I changed away from 6/7 X 16 wheels to 7/8 X 15 that give me a lower height and more tread width. The car has also been lowered so the roll height/roll center is not really going to change. I would have to go to wider fenders to get more track width so that is not going to change.

I was going to increase the rear Tbar to 28mm from 26mm but have not done anything with the stock swaybars. These RSR bars seem nice and I was thinking it may be the next area to improve. I am also aware that the stock spring plate for my 86 Carrera does not allow enough camber change so I was also thinking of going to the Elephant rear spring plate system.

winders 09-05-2012 02:23 PM

Quote:

Originally Posted by DG624 (Post 6957567)
The car handles fine but there is still some body roll. I changed away from 6/7 X 16 wheels to 7/8 X 15 that give me a lower height and more tread width. The car has also been lowered so the roll height/roll center is not really going to change. I would have to go to wider fenders to get more track width so that is not going to change.

I was going to increase the rear Tbar to 28mm from 26mm but have not done anything with the stock swaybars. These RSR bars seem nice and I was thinking it may be the next area to improve. I am also aware that the stock spring plate for my 86 Carrera does not allow enough camber change so I was also thinking of going to the Elephant rear spring plate system.

The only reason to go with the RSR-style anti-roll bars is if you need the bars to look like the RSR parts. Otherwise, save yourself some money and get the standard Tarrett anti-roll bars.

Scott

RichardNew 10-23-2012 04:34 PM

http://forums.pelicanparts.com/uploa...1351038768.jpg

Speaking of sway bars. Check out the mounting arrangement on the 908/3.

Richard Newton
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