so a friend linked me to this although it is for the m coupe. can it be used to diagnose issues with the handling of the/my s2k?

http://www.trackhq.com/forums/attachment.p...28&d=1175772451

http://www.trackhq.com/forums/attachment.p...27&d=1175772451

thnx in advance!!

 

IMO that chart is pretty much useless because it deals with huge generalities, and even some of the generalities it makes are wrong.

For something a bit more in-depth, but still pretty simple, check out Carroll Smith's ''Pocket Engineer" - that may not be the exact name of it, but it's something like that. Search Amazon for it.

 

thnx ill check it out

 

I hope that the chart labeled "Oversteer" means "If you would like to have more oversteer", and likewise with "Understeer"...

 

The chart is specific to the Z3 Mcoupe. The BMWs have so much loss in grip due to body roll that adding a stiffer sway bar on the front actually decreases understeer and stiffer on the rear decreases oversteer. This is opposite of most other cars.

The suspension does not act like a typical suspension until some roll stiffness is added.

 

Someone read the print at the top before taking everything for face value.

 

I read and understood that the chart was meant for the M Coupe specifically. I have known for a long time that the front camber limitation of the M Coupe means that a stiffer front swaybar can actually increase front grip. However, the reason it does so is that it reduces body roll and allows the front tires to have a flatter contact patch. A sway bar at either end of the car will do that (the front can't lean more than the rear!). A stiffer front bar may decrease understeer, but a stiffer rear bar will do a better job - and will not decrease oversteer!

All the shock and spring adjustments are backwards, too. The M Coupe isn't that abnormal.

 

nm

 

Original poster, this won't help you much, go to any bookstore and read through the how to make your car handle for the basic principles, I like F Kuhn's book.

We went down this road last week. I posted a game/RC link for some knucklehead who wouldn't get it but loved adhominim. (not you Ortho)

Each car has particular peculiarities. The link car is RWD +, but uses struts =/-, and has some weight/balance issues.

Our suspension is much better in stock form. A stiifer front bar in our car improves handling only if you have too much "roll", need to control the rear oversteer, are limited by the SCCA and have too much rear lift. The means that the bar accomplishes this magic is that it transfers weight faster/more than the other end.

Weight transfer, on a properly designed suspension, REDUCES TRACTION AT THAT END. Yes, you heard it right. Stiffer is not automatically better. It is a tool to solve a given problem. (If you are oversteering and can't drive, you need a bigger front bar to reduce the front traction relative to the rear.)

Take the rear bar off. Much better rear raction, so no oversteer but you wiil get wicked understeer in staggered tire. Ah, but the increased rear roll changes how the car feels. But it is virtually the same (subtle roll differences) as stiffening the front bar, front spring, and shocks (turn-in only).

But our car in AP2 with staggered tires and stock suspension, while vastly better than most cars, is still understeer dominant. It still understeers with same size tires F/R. You can *make it* oversteer by turning in early, abrupt driving, air pressure, ice/sand/rain, but in a g-circle it will understeer.

But most people really don't want a perfectly neutral car because you have to pay attention all the time.

 

I think you mean Fred Puhn. I like that book too. Very good at explaining the fundamental principles without resorting to much math. It won't turn you into a suspension designer, but it will help you understand how different adjustments will affect your handling.

The title of the book is How to Make Your Car Handle.