I agree absolutely with the autox comments, it only makes sense.

As far as stability and turn in, I'd imagine one could finesse damper stiffness/bias, sway bar stiffness, tire profile, and toe to allow for a crisp neutral turn in while maintaining high speed stability. Then again, maybe I'm just being overly optimistic

 

^I'm sure that's true, but if you could get good stability from a proper wheel choice, that would allow you to tune the other suspension parameters for maximum performance, as opposed to covering up an issue introduced by an sub-optimal wheel choice.

I went to a racing shock seminar once, and the presenter talked in terms of every parameter in your suspension having a optimum value from a performance perspective for any given set of conditions. Think of it as a XY graph, with the Y axis being, generically, performance, and the X axis being whatever it is you are adjusting (scrub radius, spring rate, shock valving, whatever). Your job, when setting the car up, is to stack all those graphs up on top of each other, whith each variable tweaked to reach it's individual max perfromance, so that the entire system delivers best perfromance, period. If you introduce a problem by setting some variable sub-optimimally, then you end up having to tweak other variables to cover that problem up, and the performance of the system as a whole falls off.

Of course, this is a conceptual model, not a real one, but it serves the purpose well enough. And, as others have stated, such optimizations only really matters if you are actually racing and your driving skills are a match for those you are racing against.

 

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surprised Team hasn't chimed in

 

Yes, it would be interesting to hear from Team & EricMeyer, among others.

 

Paging Mr Meyer? Lol

Team seems to always have cones on his mind, I can't see hist post in this thread differing much.

 

You basically said right there what I was trying to say, but you said it better. Designing a race car is all about optimizing each individual component. But, as soon you the pieces start going together, you'll find that compromises have to be made. For example, on our Formula SAE car, I designed the steering and suspension. In the modeling, I had the steering rack right where I wanted it, but ended up having to move it backwards and up 20mm to allow for our 2nd drivers' legs. I fit just fine, but it was really uncomfortable for him.

In the end you still can design a very good car, but each one has its compromises. And each one you build can get a little bit better as you tweak here and there.

Same thing goes for setting a car up. At one track with lots of sweeping and high speed corners may need one setup, where as in auto-x you need something that is more "point and shoot".

Basically, in the real world there is no one "optimal setup" for everything.

 

The posts really compliment each other well, thanks for sharing your knowledge/viewpoints guys

 

Exactly. Even for a given car/driver/race track, the optimum setup may change depending on conditions.

What CAD tool did you use for you modeling? Sounds like a fun project. Back in the day I did the HPV for my Mech. Engineering senior project.

 

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i put my stock wheels on today for tomorrow's autox. (I thought about using the aggressive wheels for autox cause I was too lazy to switch wheels but i felt that setup would not be conducive to a quick, tight course.) Anyway, took it for a drive and the oem wheels make the car definitely feel quicker and lighter on it's feet. I'm glad i didn't sell the stockers.

Just wondering if the racers out there using conservative offsets in the 40s with wider tires notice any difference from the stockers. More steering effort just from the wider wheels and tires? What would be the happy medium?