3 ms·
blipping the throttle while clutched to match RPM between the forced road speed and given engine RPM during a gear shift to alleviate weight-shift(heel-and-toe)
by serf 12y ago
blipping the throttle while clutched to match RPM between the forced road speed and given engine RPM during a gear shift to alleviate weight-shift(heel-and-toe) is still possible on modern cars, but that is not the technique that is being mentioned.
the technique being mentioned is more akin to 'left-foot braking', a technique used to pivot the weight balance from the rear to the front in order to induce certain driving characteristics that may be beneficial in a turn. It is a common technique to balance out the inherent understeer of a front-wheel drive car to a more neutral balance mid-turn in an effort to reduce lap times. It's quite common in rally.[0]
and as was said, many cars disallow left-foot braking now; with the worst responses triggering semi-permanent CELs (CELs which require mechanic intervention, as opposed to being clear by more drive-cycles).
Probably not a bad idea, as it's an advanced technique that quite easily upsets a car mid-turn, and is often just compensatory for an ill-setup race car.
[0]: http://en.wikipedia.org/wiki/Left-foot_braking http://en.wikipedia.org/wiki/Left-foot_braking
- sliverstorm 12y agoYou're mixing up techniques. Heel-toe is so called because you are using your right toe to operate the brake and your right heel to operate the gas pedal (at the same time) while the left foot operates the clutch. The technique is used in racing during corner entry to allow the driver to rev-match downshift while under hard braking. This way they are already in the optimal gear as they release the brakes and initiate the turn
- pedrocr 12y ago> the technique being mentioned is more akin to 'left-foot braking' Both heel-and-toe and left foot braking require revving up the engine under braking. The difference between the two is if the car is in gear and the clutch engaged at the time. Maybe modern cars have enough sensors to know if the engine is actually driving the wheels so they can disable the throttle under braking in those situations.
- kw71 12y ago> Maybe modern cars have enough sensors to know if the engine is actually driving the wheels so they can disable the throttle under braking in those situations. This is possible, any car with traction control has wheelspeed sensors for all wheels, and manual shift cars have a pushbutton switch on the clutch pedal arm (for enabling the starter, or for a car with electronic throttle, for cancelling the cruise control.)
- pedrocr 12y agoThose are not enough. You need a sensor in the gearbox itself to know if you are in gear. Otherwise you can have the clutch engaged and the wheels spinning but not have the engine connected to the wheels as naturally happens in the middle of a double clutch shift.
- kw71 12y agoCouldn't it work by checking that crankshaft speed increases remarkably without any corresponding increase in wheel speed? I don't know how racetrack drivers do this, but when I downshift, the crankshaft has some opportunity to fall a little while I get the gearbox in neutral and engage the clutch again. Then the crankshaft speed rises to 4000 rpm or more.