the turning circle *****

ViperGTS

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yes. the amount of countersteering available is very limited.
so - if the rear swings out more than the (fastest) countersteering can correct - the car will continue to turn around...that's at least the "principle" we have tested many many times in a safe place.
 

lh4x4

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Sorry, but I will not teach you how to do an illegal u-turn at an intersection.
 

Tom F&L GoR

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Look up how the steering of a drift car is modified - a significant feature is to increase the angle the front wheels are able to turn.
 

slartibartfast

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... and also there is quite a bit of scrubbing, when in full lock the turning radius path of each tire becomes less concentric, fighting each other to turn on a different radius center.

I'm willing to bet the Viper has enough Ackerman built-in that differential radius scrub isn't the issue. I'm in the wide tire interference camp.
 

2000_Black_RT10

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I'm willing to bet the Viper has enough Ackerman built-in that differential radius scrub isn't the issue. I'm in the wide tire interference camp.

Didn't know there was a different camp, just chatting about tire scrub based on experience.. but unless you come up with a clever rack that can provide independent rack travel for the left and for the right side, the tires will always try to scrub (or slip) inside or outside of the ackerman circle. The ackerman circle is the sweet spot in which the left and right tire follow a concentric turning radius (includes the rear tires) and the last thing the manufacturer is concerned with is tuning the steering geometry at full lock for raide and handling conditions such as higher speed bump steer, camber, dive, roll, etc.. and more of less... full lock is an infrequent parking lot manuever and scrubbing does not really impact driver handling feedback at very low speeds other than wearing out your tires.. There's the slip angle, the limit that the tires can withstand scrubbing since they can flex, the slip angle is generally around +/- 6 degrees for typical tires (stiffer and lower profile can be less), whereas the tire will flex within this angle maintaining tire patch contact inside or outside of the ackerman circle. There's other tricks to assist a turning radius such as a dynamic / virtual outboard king pin axis on Ford's CD338 platform (i.e Ford Fusion) front suspension and a trick lower control arms setup (rather than a single 3 point lower control / a-arm like a Viper, it is comprised of 2 separate lower arms with 4 points with 2 lower offset ball joints on the knuckle and a conventional upper a-arm like a Viper with one ball joint on the knuckle).
 
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2000_Black_RT10

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Very interesting video. I would guess there is a connection somewhere between the difference in turning radius that ties to the amount of vipers that are wrecked in spin-outs by new drivers:dunno:

Robert, it is a conventional suspension design, tend to generalize that the majority of spin-outs are caused by oversteer induced by the almighty low end torque of the V10, especially with a quick climbing torque curve that is quite unique unlike any other car that new Viper drivers are accustomed to..
Mike
 

RTTTTed

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Yah Mike!

I think that the turning circle is good for a normal sized car. If you think it's too large I will guess that you're coming out of a little/compact car.

I tried drifting in a circle at VOI X and learned that PS2s have amazing traction in the wet and squeal same as dry pavement. Also, I need way more practise if I want to do much drifting.

[media]http://www.youtube.com/watch?v=hehAZeGAKiE[/media]



Ted
 

PacificSEASnake

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My Viper has the best turning radius of anything currently in my stable. In fact, the only car I've ever owned that turned tighter was a Honda CRX.

You must have some ridiculously tight intersections to not be able to make a u-turn.

What I want to know; why my F-250 can't make the same turns as I can in the Viper? Really annoying having to jump curbs 'n such without even getting into 4-high.:lmao: Anyone have a contact at Ford to complain to? :dunno:
 

Tom F&L GoR

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Didn't know there was a different camp, just chatting about tire scrub based on experience.. but unless you come up with a clever rack that can provide independent rack travel for the left and for the right side, the tires will always try to scrub (or slip) inside or outside of the ackerman circle. The ackerman circle is the sweet spot in which the left and right tire follow a concentric turning radius (includes the rear tires) and the last thing the manufacturer is concerned with is tuning the steering geometry at full lock for raide and handling conditions such as higher speed bump steer, camber, dive, roll, etc.. and more of less... full lock is an infrequent parking lot manuever and scrubbing does not really impact driver handling feedback at very low speeds other than wearing out your tires.. There's the slip angle, the limit that the tires can withstand scrubbing since they can flex, the slip angle is generally around +/- 6 degrees for typical tires (stiffer and lower profile can be less), whereas the tire will flex within this angle maintaining tire patch contact inside or outside of the ackerman circle. There's other tricks to assist a turning radius such as a dynamic / virtual outboard king pin axis on Ford's CD338 platform (i.e Ford Fusion) front suspension and a trick lower control arms setup (rather than a single 3 point lower control / a-arm like a Viper, it is comprised of 2 separate lower arms with 4 points with 2 lower offset ball joints on the knuckle and a conventional upper a-arm like a Viper with one ball joint on the knuckle).

My Daimler Charger has this virtual system (so includes 300C, Challenger, etc?) and it seems just as good at feathering the outer tread block as a conventional upper/lower arm system.
 

2000_Black_RT10

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My Daimler Charger has this virtual system (so includes 300C, Challenger, etc?) and it seems just as good at feathering the outer tread block as a conventional upper/lower arm system.

I wouldn't say that this resolves scrub at full lock, especially with wider tires the impact of castor will cause the outer (or inner depending) edge to scrub, such as in a situation in which the left tire is being steering to the left the outer edge will be lower than the inner edge of the tire, and this variable is related to ride height. Moving the king pin towards the center of the tire will improve steering (i.e. hitting bumps will provide less driver feedback because the tire isn't being torqued about an inboard king pin axis, and this also helps torque steer for front wheel drives) as with the virtual system, but more joints = more compliance especially with rubber bushings.
 

2000_Black_RT10

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Tom, since I can do this relatively quick because of my daily job.. I made a 3D kinematic demo for you illustrating if a virtual king pin axis with 2 lower control arms with 2 lower ball joints on the knuckle, shortened the upper conventional a-arm a bit to slightly exaggerate the effects at full lock as mentioned. As the tire is reaches full steering lock to the left or right, the tire tilts and outer edges of the tire will encounter more wear and especially when the left and right tire is not on a concentric turning circle. Only the left side is shown in this demo.. why your outer tread blocks are feathering..
Cheers,
Mike

Video:
http://www.wincom.net/mnllehti/2000_Black_RT10_Virtual_King_Pin_Demo.wmv

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Martin

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I've been in a few situations where I wanted to do a U-turn but I had to take the inconvenient route instead... There are plenty of roads around me where the only way to do a U-turn is to go onto the shoulder - and there's a 3" or 4" drop between the pavement and the shoulder. No biggie in the Jeep, but the Vipers make really awful complaint noises if I try to force the situation... On some regular (civilized) U-turn lanes, you do have to plan them out a bit - it ***** to just barely not clear the curb on the other side. It must be a boring night to be discussing this :)
 

Tom F&L GoR

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Tom, since I can do this relatively quick because of my daily job.. I made a 3D kinematic demo for you illustrating if a virtual king pin axis with 2 lower control arms with 2 lower ball joints on the knuckle, shortened the upper conventional a-arm a bit to slightly exaggerate the effects at full lock as mentioned. As the tire is reaches full steering lock to the left or right, the tire tilts and outer edges of the tire will encounter more wear and especially when the left and right tire is not on a concentric turning circle. Only the left side is shown in this demo.. why your outer tread blocks are feathering..
Cheers,
Mike

Video:
http://www.wincom.net/mnllehti/2000_Black_RT10_Virtual_King_Pin_Demo.wmv

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Very cool, thank you. Very unlike the typical American car geometry.
 

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