is there a general rule of thumb in difference between low speed cornering with tighter corners and higher speed larger corners? I'm gussing less over steer for the larger corners. any difference in f/r spring ratio setups?

 

Your guess is correct and this is where aero balance can be used to trim the car, since downforce grows with speed.

Speaking strictly from a mechanical grip point of view, it is pretty tough to make balance change at different speeds but it is handy that high speed corners are of a larger radius than slow ones. You can use castor or Ackerman effect to change balance or turn-in because they realize geometry changes resulting from steering input - and you use more on a slower corner.

K

 

thanks for the reply but i'm not sure i followed the last part "to change balance or turn-in because they realize geometry changes resulting from steering input" - and especially this part "and you use more on a slower corner." I'm a bit of a layman, is this saying that you compensate for the mechanical settings of dampers, etc that are tuned for higher speed cornering on the low speed tighter corners by changing alignment specs? I'm guessing that this is one of many ways to do this. just curious-thanks

 

Kirk,

I don't think he's read "Tune to Win" yet...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FormulaIntegra &raquo;</TD></TR><TR><TD CLASS="quote">Kirk,

I don't think he's read "Tune to Win" yet... </TD></TR></TABLE>

but i will now, who's the author?

 

Carroll Smith

 

Heh, it's always easy to tell.

 

thnks for the tip, trying not to be to conspicuous about the noobdom

 

Nah, you're not. It's just a good book to read that answers a lot of basic questions like that so you can get down to the details of what to do and how to do it.

Some people here (like me) act a little bit more knowledgable than they really are.

 

Low speed corners can benefit more from increased caster, since the turns require higher steering angles. Something to think about if you're planning to do a UCA switch...

 

is there a downside to having a lot of caster in a big sweeper? I'd think any camber gain once you've cut the wheel would be of assistance, since you're still likely cornering on the edge of adhesion, getting a wee bit of decambering due to roll, and you're still loading the tire quite a bit. Any idea how one would go about finding what is "too much" caster?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WRXRacer111 &raquo;</TD></TR><TR><TD CLASS="quote"> Any idea how one would go about finding what is "too much" caster? </TD></TR></TABLE>

There are some good articles out there that I'll have to track down. Many people feel you can't have too much caster, but I rarely see people trying to get more than about 5 degrees. As you increase caster, you increase your steering effort and turn in can become difficult. I also recall people discussion a feeling of "roughness" if caster is adjusted beyond the ideal range, but I'll have to find the actual article I was reading.

 

From what I've read "too much caster" usually can't happen within the limits of most production cars' suspension geometries.

 

Caster won't help you as much in fast corners because you aren't steering as much. As a result you won't get much camber gain. Caster also has a tendancy to transfer weight to the outside front tire, i.e. the one that is already the most overworked. Look at a go-kart some time, they use this to their advantage since they have no differential and want as much weight off the inside rear tire as possible