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Originally Posted by Dean
If you have the room, hollow gievs you more spring for less weight.
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Yes, basically use tubular bars wherever possible to achieve the stiffness you're after; you'll end up with less weight than if you used a smaller diameter solid bar to get the same stiffness.
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Originally Posted by Dean
Having multiple arm lengths by way of moltiple holes for end links lets you change the relative stiffness by lenghtening and shortening the lever arm.
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Yup.
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Originally Posted by Dean
I am not sure what adjustable length end links do since they don't appear to change the lever arm length.
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The adjustable length lets you ensure there is no preload on the bar, and also lets you adjust the height of the bar/endlink connection point so that the bar's lever arm is level. If the lever arm is not level, it basically affects the motion ratio and you lose some of the bar's effectiveness (wheel rate), since the connection points will be translating fore/aft in addition to vertical movement as the body rolls.
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Originally Posted by Dean
There are definitely a holy war on big springs vs. swaybars. I'm betting a well balanced system might be best, but th eopinions are all over the map.
If I understand the arguments. The swaybars are bad argument is that they lift the inside tire unncesarily reducing it's ability to assist in turning due to reduced contact patch/friction.
The swaybars are good camp says they reduce body roll without requiring increased spring rates thus improving tire contact all around.
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Reading Carroll Smith's books helps for a good overall understanding of things. Swaybars do have some negative effects, such as reducing the independance of the suspension; but with heavy production cars such as ours, they are almost always necessary to keep body roll within acceptable limits. Basically they do more good than harm. The entire purpose of the swaybar is to limit body roll, since it's a simple torsional spring that only has any resistance in roll. You could easily run a car with no swaybars at all and limit body roll with springs alone, but to do so will typically require springs that are so stiff as to reduce tire compliance with the imperfect surface of the track to an unacceptable level.
The way I'm thinking about things right now is that it will probably be fastest to run the stiffest springs possible (
without reducing tire compliance - that's the key here), and then use bars as necessary to reduce body roll to your acceptable level. The tire compliance bit obviously varies from track to track, which is why race teams spend endless hours practicing and tuning and optimizing at as many tracks as they can.
At the end of all that you might ask the fundamental question: why is body roll bad in the first place? It doesn't cause weight transfer, contrary to a lot of popular beliefs; it's a result of lateral centripetal acceleration towards the center of the turn (Overall lateral weight transfer from the inside tires to the outside tires is geometrically fixed by the car's layout; it's C.G. height, it's track width, it's weight, and the amount of lateral acceleration present.). Body roll is primarily bad because it 1) affects tire camber since the tire's camber angle is linked to the roll angle of the chassis through the suspension, and the tire camber angle is critical to how much lateral force it can develop; and 2) because roll is a transient; the body takes a finite amount of time to roll, during which the driver is sort of waiting for things to happen. The less roll angle we get, the shorter amount of time it's going to take. There are also some other aspects of the process that can be discussed at length and in detail, such as the different components of weight transfer from sprung mass vs. unsprung mass, and through the roll centers, etc. etc... but I don't think it's critical to this particular discussion.