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 Post subject: IC question
 Post Posted: Tue Nov 30, 2010 5:35 am 
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What effect does the height off the ground make having the same length?? Another words say its 10" now and move it to 4"... :-k

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 Post subject: Re: IC question
 Post Posted: Tue Nov 30, 2010 4:33 pm 
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I would think Barry that it would be working less to lift the car in front vs the COG location, the higher it is per setup would make it chase it to the higher location causing more lift, more squat or however you have the chassis set up, jmo though, let's see what Shrinker and Mark and the others say. Would all else be the same, but just change the I/C heigth????

I know when I had my I/C 2 " above the nuetral-A/S line and 3" in front of my high COG of 21" that it had barely no seperation, or squat, and I have the info to prove it that it did neither with video, charting and graphs complements of a great racer from down under=; Then I changed it to be about 9" off the ground and way below my COG but still in front of it and I blew the rubber right off instantly, but of course I am still testing to find my sweet spot and mine seems to like high and far out due to my high COG and weight balance and chassis setup.
I would think yours will be a lot different being a tube chassis car and having a much lower COG, plus you have them sticks out the back to work with them wheels on the ends \:D/ I would say to watch a lot of Comp. Elim. cars and watch how they leave as they seem to all have things working reeeeeeeal good for that class. again, jmo.

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 Post subject: Re: IC question
 Post Posted: Tue Nov 30, 2010 6:14 pm 
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Lower IC is less hit on the tire, less rear suspension separation or more squat.

Rick


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 Post subject: Re: IC question
 Post Posted: Wed Dec 01, 2010 9:34 am 
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rick360 wrote:
Lower IC is less hit on the tire, less rear suspension separation or more squat.

Rick


Thanks Rick =; =; =; some day I will figure all this out with suspensions :-k

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 Post subject: Re: IC question
 Post Posted: Wed Dec 01, 2010 6:04 pm 
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Location: Orlando, FL
Beretta wrote:
What effect does the height off the ground make having the same length?? Another words say its 10" now and move it to 4"... :-k

All lines of constant percent antisquat pass through the rear tire patch (side view), with each value having a different slope. So, if the "up" goes from 10 inches to 4 inches while the "out" remains unchanged, the IC is sitting on a constant percentage line of lower value. This means hit/separation is decreased.

If, however, the "up" remains at 4 inches, but the "out" is decreased sufficiently, the IC will again fall on the same antisquat line corresponding to the original 10 inch "up" and performance will be unchanged.
http://www.racetec.cc/shope


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 Post subject: Re: IC question
 Post Posted: Thu Dec 02, 2010 10:53 pm 
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Beretta wrote:
What effect does the height off the ground make having the same length?? Another words say its 10" now and move it to 4"... :-k
That will cause less weight addition to the rear tires due to the torque arm being counteracted and forced down more by the forward drive of the axle housing. The axle housing is higher than the IC in this case and it drives over the top of the IC forcing it down. That force counters the upward lift due to torque reaction so the result is less lift of the CG of sprung mass. However the springs will compress more due to the total weight transfer having to be the same because the CGH hasn't been altered so the weight transfer will occur slower and different curving of transfer and will be influenced by the shocks more. The weight that's not transferred via the 4 link will be transferred via the springs for the same fully reacted steady state conditions, its just getting there differently that's all. In basic terms the Snap; off the line will be softer.
The spring will be compressed more so the final geometry of the 4 link will be differnt so the total weight transferred wont be exactly the same. 4 link geometry is interactive not a static state calculation.


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 Post subject: Re: IC question
 Post Posted: Sat Dec 04, 2010 7:19 am 
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If, however, the "up" remains at 4 inches, but the "out" is decreased sufficiently, the IC will again fall on the same antisquat line corresponding to the original 10 inch "up" and performance will be unchanged.
http://www.racetec.cc/shope[/quote]





Can't quiet grasp that??? If the IC is decreased with that same 4" there will be no change?? So basically your going to drop the top bar a hole in the front and there will be no performance change???? #-o

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 Post subject: Re: IC question
 Post Posted: Sat Dec 04, 2010 10:22 am 
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BillyShope wrote:
If, however, the "up" remains at 4 inches, but the "out" is decreased sufficiently, the IC will again fall on the same antisquat line corresponding to the original 10 inch "up" and performance will be unchanged.
http://www.racetec.cc/shope






Beretta wrote:
Can't quiet grasp that??? If the IC is decreased with that same 4" there will be no change?? So basically your going to drop the top bar a hole in the front and there will be no performance change???? #-o

Picture, in side view, a line through the the 10 inch IC and the rear tire patch. Then, picture a line through the 4 inch IC and the tire patch. If you draw a horizontal line through the 4 inch point, it will intersect the line through the 10 inch point. So, if you pull the 4 inch IC point back from its original location and place it at the intersection, both the 10 inch IC and the 4 inch IC will have the same percent antisquat and performance will be unchanged. (The rest of the car "feels" only the resultant tire patch force, which acts on a line through the tire patch and the IC, which is equivalent to a line of constant percent antisquat.)
http://www.racetec.cc/shope


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