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Old 06-11-2004, 12:44 PM
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Originally posted by Gord96BRG
From a strictly textbook approach, I would have agreed with you. However, Tim (tpryor), the one suggesting that a bigger front bar on an RX-8 decreases understeer for autocrossing, actually has an RX-8 that he autocrosses very successfully, and HAS experience with that mod, and explained why it works.
Ditto this, I took Tim's advice, and it worked for me. I've used this setup in 4 autocross events now, I'm not doing anything differently from a driver-perspective, the car simply turns in better.
-Debbie
Old 06-11-2004, 12:50 PM
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Originally posted by tpryor
Nope.

If the car sits down on the bump stops, the spring rate goes to infinity. By increasing the size of the bar, the spring rate does not go to infinity, as the stiffer bar forces it to stay on the spring, thereby EFFECTIVELY reducing the rate, and the push is diminished.

You have heard other members say it works also. So, the proper equation would be:

Bigger front bar=more front roll stiffness=less effective spring rate=less understeer
This assumes that you dont put the car onto the bump stop even with the stiffer front roll bar.
Look at FWD cars- limit behavoior is rear inside wheel off the ground.
Look at RWD car- limit behavior is front inside wheel off the ground.
Ultimately, limit behavior will give more understeer even though the ultimate limit might be higher
Whatever Autox and have FUN:D
Friends of mine were shocked when I got THREE wheels off the ground. I never said I was good, but always tried hard.:D

Last edited by Seenitall; 06-11-2004 at 01:48 PM.
Old 06-13-2004, 03:51 PM
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You have heard other members say it works also
Yes, it does work. Normally a stiffer front bar would create more understeer, but in the RX8, with its high polar moment of inertia, it helps prolong it.

You will notice a drastic improvement by changing to stiffer sway bars.
Old 07-11-2004, 12:44 PM
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Thumbs up

Originally Posted by Gord96BRG
trex8, Lawerence:

Nice theories you have there. Have you actually tested them on an RX-8? (Both of you state categorically that a bigger front bar will result in more understeer).

From a strictly textbook approach, I would have agreed with you. However, Tim (tpryor), the one suggesting that a bigger front bar on an RX-8 decreases understeer for autocrossing, actually has an RX-8 that he autocrosses very successfully, and HAS experience with that mod, and explained why it works.

Hmmm, who should we listen to - the guy who has actually run a bigger front bar on an RX-8 and is winning his class in autocrosses, or the guys who haven't tried it and are just stating generic theory?

Regards,
Gordon
I'm listening to the guy who is running the stiffer bar. :D

Great info guys.
Old 07-12-2004, 07:55 AM
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few things- I'm not an expert, but I am told I'm better than average, so I'll lend some things that I hve learned from one of the greatest drivers I've ever seen- imp on this board

slow in, fast out - a must with the stock setup, every car, and I can most definately say even the Evo understeers out of the box. It is a safety feature that car manufacturers build into the handling characteristics of a car. The last car that didn't have this built in was a ford in the 1970's I think- it only lasted a year with that setup. Remember, most of America can't drive

Smoothness rules, that is all

as for trailbraking- haven't really tried that yet, and though I'm decent with LFB, at least with my subaru, I haven't tried it with the 8, probably the next one

the car definately needs stiffer springs or something, the front definately dives huge amounts under braking. Didn't really notice until another instructor/great driver took my car out.

and if anyone else is reading this after all that- anyone notice a ticking sound under hard/ sustained turning= kind of like rocks coming up and hitting something in the wheel well.?
Old 07-12-2004, 08:28 AM
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Originally Posted by Reaper Man
and if anyone else is reading this after all that- anyone notice a ticking sound under hard/ sustained turning= kind of like rocks coming up and hitting something in the wheel well.?

Sounds like you need to go with the new torque specs on the front studs. Check the TSB on the subject over in Tech.
Old 07-12-2004, 10:22 AM
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Originally Posted by islandsoon
Sounds like you need to go with the new torque specs on the front studs. Check the TSB on the subject over in Tech.

will do, thanks
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