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Old 05-20-2012, 10:45 PM   #82
Dimman
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Quote:
Originally Posted by Moto-P View Post
I like to setup balance as much as possible using springs and shocks then only if I see it necessary, tune it further with larger sway bars. This is because one variable is easier to deal with on overall combined spring rate that works on all three axis, that can be precisely controlled by the dampers.

I'm not saying I don't use it, but merely stating that it is the last thing I touch, and sometimes the most difficult, and combined rate can seem awkward in handling to me when lateral and longitudinal tilt/dive amount seems grossly different.

But this is one of those things, where individual flavor has more to do than exact science...
I like cars that roll a bit, and at rate of descent precisely controlled by the shock absorbers.
It feels very tanacious when you get it right, and enough body roll can be synced to speed and motions that work well with the given chassis and tires, where each snap of hard left or right can load the appropriate tires aggressively and quickly, and that yaw be controllable also by brake ot throttle, and be relieved of it just as easily and redirected to your next input.

Making a car corner too flat makes this transitional phase very short and snappy and driver error makes it hard to time well. Being theoretically quicker ideally, but often not and less fun to drive. Less docile when things are stiff and unintuitive.

On cars like the FRS sway bar tuning is even more complicated as its a very light car with low center mass, so there isn't much pitch, dive, and sway in the first place... So that slightest change can really start to prevent things from rolling at all, which can't be all good.
I would say as far as, I probably wouldn't go larger on them unless tires in question are the most aggressive of racing slicks that are enough to roll it that far that fast...

And even then, I'd still would probably work with that much harder spring/shock to hunker on those forces, and sway bars may still be optional to me... Only being a tool I use mostly if this is a dedicated car for very fast tracks with long high-G sweepers well into top of 3rd gear, and speeds I'm less comfortable with tenacious weight shifts... But that's one of those scenarios I rarely encounter, as most of my thrills come from smaller venues like autocross, small to medium road courses, and safe casual passes through twisty rural hill passes.
Thanks.

I'm starting to get more technically involved in suspension theory. What I'm looking at is setting up the springs for a .9f/1r frequency ratio (looking like 250/390 f/r but with some big assumptions on unsprung weights and rear motion ratio until I get get some real measurements...), sorting out the damping ratios and slopes for them and then using bars to balance the remainder of roll front to rear.

Am I on the right track?

Edit: with those rates and my weight and motion ratio estimates I was looking at ~1.77Hz front and ~1.94Hz rear.
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Last edited by Dimman; 05-20-2012 at 10:48 PM. Reason: edit
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