Your opinion on Wishbone.exe setup

[tnttim]

I was wondering if all you real technical bored people would have a look at the Wishbone.exe settings I was thinking of using for the rear of my IRS setup.

 

Now keep in mind that the Lower A arm points both inner and outer are set, and I am not going to move them now.

 

The upper A arm is open for moving any of the inner points pretty much anywhere.

Also the inner point on the control arm is movable for toe in adjustment.

I also have to keep all the measurements on the spindle and the widths the same due to the cv joints.

And I don't mind the 1.2* of camber, since in heavy corners I will rub the outside of the tire off anyway. Should even out. :yesnod:

 

Also looking for any volunteers who wish to come and weld the suspension together,, hehe. :smash:

 

http://www.usa7s.net/aspnetforum/upload/1744808544_wishbone.JPG

 

 

 

Constructive suggestions appreciated.

 

tnttim

 

 

[JohnK]

Well . . . I'll offer a goal I've come up with after spending way too much time trying to understand suspensions. The tire wants pretty much to be flat on the road when it's keeping the car in a turn, if it's gonna give you maximum traction. The suspension changes, among other things, the camber when the chassis moves. Make a guess based on what you figure might be the lateral G that your car can generate when in a turn and then jiggle things around so that the change in camber that the suspension produces for that condition winds up giving zero camber. E.g., I know that my car at .8 G will generate around 1 degree of roll at neutral throttle while in a corner. Therefore , I set my alignment so that, for a chassis roll of 1 degree the camber gain from the suspension movement results in 0 degrees of camber - at 0.8 G the tire's flat on the ground (at least with respect to camber).

That gets you from one particular suspension configuration to where to set the alignment. To see the advantage of a different suspension configuration (different chassis pick-up points) repeat, looking for the smallest change in camber in the neighbourhood of where you want to be driving. And then there's scrub and caster. I used Wm. C Mitchell's WinGeo3 for doing suspension geometry and a companion program called WAN31 by a guy named Warren Rowley which allows you to calculate load transfer. (If anyone know of a good 12-step program for people in my condition, I'd appreciate them passing it on.)

 

 

PS. Very general rules for Se7en-type cars: The front roll center should be somewhere around 5-6 inches off the ground, the rear roll center can be on the ground (parallel A-arms), a front anti-roll bar makes things work a lot better but can be difficult to fit and tune.

 

Best of luck.