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  #11  
Old 02-17-2010, 02:57 PM
Def Def is online now
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The stock bushings act like an undamped spring with travel. Twisting that little bushing by even a few degrees takes a lot of force. Multiply that by 3 for each side(plus 2 rlca bushings) and it's very significant. They do bind some as well due to their unwillingness to axially deflect as well.
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  #12  
Old 02-17-2010, 03:25 PM
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Yes. With the car on 4 jackstands, the jack under the balljoint, and the coilover/sway removed, the car would start to lift past 2.5" on some configurations. And it's more than teetering, since I've got the front jackstands way way forward by the toe hooks. I've done it before with sphericals. The bind forces are in the directions of the arms. Basically, the traction arm is a lot shorter than the RUCA and toe arms. It starts pulling in sooner, which fights the other arms that aren't at such a radical angle. Once the bushings are fully loaded, the car starts coming up.

But, lets be honest here. 2.5" is a lot of travel under compression. That'd put my fender half way up my sidewall. Not to mention the weight transfer needed to accomplish this with moderate spring rates.
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Old 02-17-2010, 03:28 PM
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Quote:
Originally Posted by Def View Post
The stock bushings act like an undamped spring with travel. Twisting that little bushing by even a few degrees takes a lot of force. Multiply that by 3 for each side(plus 2 rlca bushings) and it's very significant. They do bind some as well due to their unwillingness to axially deflect as well.
I actually loosened the bolts to prevent the "twist" bind. There is axial bind, but what was picking up the car was in-out bind. That is, in it's intended direction.
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  #14  
Old 02-17-2010, 03:48 PM
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Well this is certainly interesting data, but I'd like to verify what Im' thinking, as I could certainly be way off.



Lets assume car has 12.25 RUCA length, and the traction arm at 8.0 inches long, you'd essentially have your innside wheel (under compression) in a 'toe out' situation' and your outside (drooping) in a 'toe in' situation correct? With that assumption made, would this lead to a very 'tail happy/loose' rear, maybe best for drifting? And then when compared to the traction arm at 8.25, you'd have an instance of it acting similarly, but not so dastic correct?



I know this may sound very simple of me asking this question, but I'd rather understand what is prefered.
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  #15  
Old 02-17-2010, 04:03 PM
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............

Drift cars actually could use as much grip as possible, so the "tail happy" bit is not true for drift cars.

Maybe for your average POS broke ass 240 owners' "drift cars", but not any of the more serious drift cars have a suspension setup that is more closer to an all out grip setup than you might think.
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  #16  
Old 02-17-2010, 05:19 PM
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Quote:
Originally Posted by CodyAce View Post
Well this is certainly interesting data, but I'd like to verify what Im' thinking, as I could certainly be way off.



Lets assume car has 12.25 RUCA length, and the traction arm at 8.0 inches long, you'd essentially have your innside wheel (under compression) in a 'toe out' situation' and your outside (drooping) in a 'toe in' situation correct? With that assumption made, would this lead to a very 'tail happy/loose' rear, maybe best for drifting? And then when compared to the traction arm at 8.25, you'd have an instance of it acting similarly, but not so dastic correct?



I know this may sound very simple of me asking this question, but I'd rather understand what is prefered.
Cody, you're making my head hurt! If you're going around a corner, the outside wheel is under compression and the inside wheel droops. Weight transfer is to the outside of the car during cornering last time I tried it...,
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  #17  
Old 02-17-2010, 06:21 PM
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God I'm retarded tonight. Never cook and type at the same time~no wonder why I was confusing myself to a degree. At least the food was spot on! haha
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  #18  
Old 02-17-2010, 07:11 PM
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If you look at that lower plot with the 12.25 RUCA and 8" trac, I'll show you why that works for drifting. Because they run lower ride heights, they're sitting 1" or more up that graph. Starting up there, there's not a lot of toe change. Also, the shorter traction rod rolls the upright forward, which dials out anti-squat. All of this works great for a high powered drift car. The problem with bind is mitigated by running high spring rates and big bars, which basically keep the suspension from moving more than 1" from stationary. This also works on the longer RUCA, as a flatter tire will give better contact patch and grip.

Drifting has gone way farther 145whp cars skidding around. They need all the rear grip they can get. I can't imagine controlling some of those 450whp cars that sideways.
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  #19  
Old 02-18-2010, 07:10 AM
SoSideways SoSideways is offline
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Hmm... I don't know, looks like the 8.5" traction rod length seem to be the ticket for drift cars, as the wheel will toe in under compression?

I know some of the ziptied guys were talking about running so much toe in at static ride height that you can visually see that it's toed in, and they set it up that way so that under compression, they're still toed in and will have more traction coming out of a corner when they're trying to put the power down.

They also did it with 10mm shorter traction rod lengths than stock, so pretty short.... and I would assume that hurts the toe quite a bit, which is why they said that.

With that said, if I'm on the right track, wouldn't the 8.5" traction rod length be beneficial, especially if they're starting at 1" lower ride height than the zero on your graph, Epstein?
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  #20  
Old 02-18-2010, 08:02 AM
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I think Epstein is talking more about the Pro's with 450hp+ cars and 255+ size rear tires from Formula D.
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