It is easy to forgive a newbie when all they know is if you let off the gas the car turns in way too fast and spins out uncontrollably if they apply brakes or throttle.
Then when they complain someone here tells them to use 85/30/1, stiffen the front, increase brake bias, and just get used to it.
This leaves out any explanation of why it helps the driver if the car rotates when you let off the gas.
Rotating the car with differential coast is a driving technique described repeatedly by so far every credible source from Taruffi (50s), Jenkinson (50s), Clark (60s), Lauda (70s), taught by Bondurant School, Jim Russell School, Carrol Smith, and on up until recently Bob Boles, author of "Advanced Race Car Chassis Technology," HP Books, 2003 rev. 2010.
"Cars need rotation."
Generally, my humble fantasy preference is to not use brakes except softly to slow the car, along with downshifting, to threshold corner entry speed as brake markers are passed before a turn, counting down in rhythm with the downshifts 3-2-1 to turn-in at zero, which is where the throttle is closed, the diff goes into coast, the car rotates, throttle is applied and the suspension is locked on a vector that crosses over a point of choice at exit, while countersteer fixes the front on the default line of least resistance against the track camber thru the turn.
Others have their own ideas.
When the diff goes into coast the rear suspension relaxes and the mass at the back, no longer held in place by engine torque, heads out on its own vector at the sum of a tangent and the line of travel.
A driver can target a landmark alongside the track on the outside of a turn and by going off throttle set the rear's vector toward the target with the same certain confident precision that is required to get the car around the corner.
The rear's off-line attempt at escape is limited by its connection to the rest of the car and the tires, so all it can do is begin to "rotate" the car around its CoG and load the tire patch in an effort to relieve itself of a force with no place else to go.
This applies downward pressure at the tire patch on the outside rear which increases grip as loading approaches the maximum possible before any more excess force has no choice but to find another place to be.
From the driver's POV the best place for excess force to go is back into the springs to propel the car's sprung weight forward, which is what it will do when the car's suspension is accurately and correctly tuned.
As soon as rotation begins the front is steered into the track camber and hopefully, if toe bars and shocks are dialed-in, all four tires will settle at maximum lateral load, enjoy the same angle of attack, (neutral steering), and the car will easily negotiate the turn relying only on fully accelerating throttle from the pre-apex instant of coming back out of coast.
All in 4/5ths of a second or less.
Questions and guesses but okay, find an opening
Edited by John Woods, Jan 13 2019 - 09:01 PM.