Keeping the Snake STRAIGHT

[Aevus]

http://racetrackdriving.com/car-setup/track-alignment/

High power street car: minimally positive toe on non-driven wheels, substantial toe in on driven wheels (1/16"-1/8" per side).

High power RWD/AWD track car: zero to minimally positive front toe, substantially positive rear toe.

As you can see, the more power a car has the more positive toe it tends to run, especially on the driven wheels. On road courses this is required for stability in high speed corner entries and for the car to exit corners going straight under throttle rather than going into a drift, or powerslide, and tracking straight is obviously a desired characteristic of a street car. That said, road course cars try to minimize toe in to reduce drag and increase tire life.

A car with front toe out will initiate direction changes more easily than a car with front toe in. A car with significant front toe out will feel "darty": a small movement of the steering wheel will be sufficient to get the car to rotate. A car with positive front toe will tend to track straight even in the presence of minor steering wheel movement, which is why street cars often have a bit of positive front toe aligned into them.

When the car is in the middle of a corner, and the weight is transfered to the outside tires, front toe has the opposite effect on handling: front toe out produces understeer and a car that resists mid corner direction changes, while front toe in makes the car darty mid corner and may even cause oversteer under power in front wheel drive cars.

To see empirically why this is so, consider toe out. The inside wheel is pointing further into the corner than the car overall. However, mid corner the inside front wheel is unloaded and its contribution to the behavior of the car is minimal. Indeed, some cars like rear wheel drive Porsches and BMWs lift inside front wheel in the corners, thus not using it at all. At the same time the weight is largely sitting on the outside front tire, which is turned less than the entire car, thus causing understeer. The situation is reversed for front toe in, with outside front tire pointing further into the corner and continuing to rotate the car.

As I understand, the optimal STREET front toe would be minimal positive (like I did with my +0,05 deg on each wheel) and for TRACK it will be either neutral or minimal negative. But then again, many factors kicks in: Camber, suspension and sway bar settings, tire wear, experience of the driver, type of track, etc...

[TKO MOTORSPORTS TEAM]

thanks TKO for the input. I assume that is for optimal track times on a dedicated gen 5 track car, but what about a gen 3 that would be used mostly on the street, without consideration about track time but just how the car feels and responds?

We run the same setup on the street as we do the track. Toe, camber and caster same as track for most of our customer cars. There is no real benefit for alot of viper owners to have a street set up and track setup when it comes camber , caster and toe unless its a full blown racecar. Some of our customers who daily drive their viper and track it we will pull back front camber a bit just to increase front tire life. Other changes the customer will have us do or do it themselves is back out the compression adjustment if they are running our shocks or other adjustable shocks for a little better ride on the street. If the car has aero sometimes we take attack angle out of rear wing. This is mainly for fuel mileage since the viper fuel tanks are so small and gas stations maybe far apart.

[LCatGA]

Great thread, answered most of my questions )))))))))))))). How did all those things affected daily ride quality? Any advice on coilovers?

[Aevus]

daily ride quality is mostly affected by spring rates