Will The 1LE Sways Increase My Slalom and Skidpad #'s?

[F1GT]

You may not be an expert Bob, but you seem to have read up on the subject. The book, "How to make your car handle" - is this the book with a lowered 3rd gen. Camaro making a turn on the front cover?? If it is, I saw it in Motor Trend when I was in High School, but I can't find the article. I guess I'll have to do a more thorough search.
[img]graemlins/burnout.gif[/img]

[John_D.]

<blockquote>quote:</font><hr>Originally posted by V6Bob:
[QBThis is wrong (on our cars). The end of the car that has less roll resistance sticks better. This is basic suspension theory.[/QB]<hr></blockquote>

ummm, I don't follow this logic.
1. Implies (our cars) are somehow different than basic suspension theory. Therefore the common logic of keeping one end of the car flatter equals better handling on that end, is not correct for our cars.
2. At the same time, basic suspension theory as you understand it, must state that keeping one end of the car flatter does not improve handling on that end either.

So, help me out here, which is it? Basic suspension theory goes against my original statement, or our cars are different than basic suspension theory, therefore just our cars go against my statement?

Just trying to make sure I understand where you are coming from... [img]smile.gif[/img]

I think you are saying that some body roll introduces additional negative camber on the loaded tire, counteracting the tendency for the tire to laterally roll under the wheel, therefore increasing grip by tending to keep the contact patch flatter. This does have some merit, especially for the front end.

And it could also apply to independent live suspension rear ends, especially if they were built with unequal length control arms. But in our cars, body roll in the rear end has little camber effect, the axle remains parallel to the road (unless a tire lifts off the ground of course...). Any camber effect in the rear will go positive rather than negative due to tire compression on the loaded side and some tire lift on the unloaded side. And lateral deflection of the tire is occurring too.

Camber in this discussion being defined as camber angle relative to the road, not relative to the vehicle. The angle relative to the road is the one that affects contact patch deformation and resulting lateral friction, or lack of.

If increasing the front roll bar size is only going to create more understeer than what we already have, seems kind of pointless to upgrade the front, 'cause it will only make the problem worse.

I still advocate keeping the front and back ends balanced...

[V6Bob]

John_D. - "So, help me out here, which is it? Basic suspension theory goes against my original statement, or our cars are different than basic suspension theory, therefore just our cars go against my statement?"

The first, basic suspension theory goes against your statement. Camber is a minor factor. The main factor is that bigger antiroll bars transfer more load to the outside tire causing that end of the car to stick less well. The theory is described in great detail in "Chassis Engineering" and "Tune to Win". The practical effect, more oversteer with a bigger rear bar, is described many places. Like I say, don't trust me...

"If increasing the front roll bar size is only going to create more understeer than what we already have, seems kind of pointless to upgrade the front, 'cause it will only make the problem worse."

If the only concern was racing and going absolute maximum speed through every corner you'd be right. Driving like that on the street in insane. At any reasonable pace on public roads a bigger front bar will make the front end feel more solid and the steering more responsive. For most people that translates to "better handling".

The major drawback of setting up a street car for ultimate racing speed is that it becomes dangerously unstable on the street, as you stated very well in your discussion of why oversteer is dangerous on the street. And even racing cars are tuned to have some understeer midcorner, so as to be able to apply power early (which is critical to lap speed) and accelerate off the corner. "Driving with the rear end hung out looks neat and is a lot of fun. It's a pity it's not the fastest way around the track." - Carroll Smith

F1GT - "The book, "How to make your car handle" - is this the book with a lowered 3rd gen. Camaro making a turn on the front cover??"

My copy (an old edition) has an 70s Trans Am racing scene with a 911 and a Camaro.

[ April 14, 2002: Message edited by: V6Bob ]

[ April 14, 2002: Message edited by: V6Bob ]

[ April 14, 2002: Message edited by: V6Bob ]

[ April 14, 2002: Message edited by: V6Bob ]</p>

[John_D.]

<blockquote>quote:</font><hr>Originally posted by V6Bob:
...basic suspension theory goes against your statement. Camber is a minor factor. The main factor is that bigger antiroll bars transfer more load to the outside tire causing that end of the car to stick less well. <hr></blockquote>

Ok, I probably read more into your original comment, with the reference to "our cars". Thanks for clearing that up for me, so I'm not scratching my head trying to figure out what is so unique about our cars.

About the load vs camber thing, I'll have to research that some more. You've got me thinking at least... [img]smile.gif[/img]

I've heard the load argument before, but it seems to me, that if you hold a curve long enough for all the body roll to come in, spring and sway compression is no longer absorbing any load changes, as the suspension achieves equilibrium.

So the outside tire is still going to be loaded about the same at that point. The spring is compressed, there is the same overall tendency for the car to roll over in the turn (which is the tire loading force), and the same inertial force trying to keep the car moving in a straight line. Just the body is rolled more, and the suspension geometry comes into play more, creating the camber variable.

Unless I am missing something (hey, it's happened once before...)

[ April 14, 2002: Message edited by: John_D. ]</p>