A chance to talk mostly about Bolwell Sports Cars.
Friday, June 24, 2011
Grant, from obp has posted another tech talk.
This is a tech session on the throttle Blip and how to Heel and Toe.
The Blip is used when you are changing down a gear without loosing speed or grip. Properly done the RPM should be raised to approx 2700 to 3000 RPM just before the clutch is engaged again. You do not push the throttle and hold it, you tap it, the best term to explain it is you "Blip" the throttle, this is a quick and sharp burst.
The blip should take place just before re-engaging the clutch by doing this you will not get the shock through the drive train or slow the car down when going from a higher gear to a lower gear. In a competition environment on the race track when you are driving close to the tyres limitations of adhesion, a down shift with out a blip could cause a loss of grip and send the car into a spin or loose grip in the straight line braking zone.
Heel and Toe?
Because you are using your left foot on the clutch and your right foot on the brake, you have to make some adjustments so you can blip the throttle. The way to do this is to adjust your foot position and use a race obp pedal boxdesigned for heel and toe. You use the ball of you foot pressing on the brake pedal making sure you leave enough of the outside of the foot to roll over so you can blip the throttle. By blipping the throttle you will enable a smooth down shift with out loosing any tyre grip.
The correct brake and throttle pedal relationship should locate the throttle and brake approx 30mm to 50mm apart. The throttle is set slightly below the brake pedal when the brake is hard on. The heel and toe method is a pretty hard technique to master and requires plenty of practice. The heel and toe term was phrased over 40 years ago when the brake pedal was on the right and the clutch pedal was on the left and the acc pedal was in the middle and 6 inches lower. Then you had to use your heel and toe to blip the throttle.
As I have explained with today's pedal systems the heel and toe is not used, but the term still remains. The pedal system in most road cars are not set up for heel and toe, so drivers are forced to go through some real contortions to be able to touch the brake and the throttle pedal at the same time.
Of course Grant suggests buying one of his properly set up pedal boxes. (see obp in links).