ulix (U. Goettsch) writes:
[excellent description of theory snipped]
>H&T then, is used before curves, when the driver has to brake and
>downshift at the same time. He uses the toe to press the brake and
>the heel to press the gas to rev the engine to the right speed.
Well, almost. In practice, it's usually done with the ball of the foot
(or the big toe) pressing on the brake pedal, and the side of the foot
(under the little toe) sort of rocks over to the gas pedal and blips it.
It's usually done under braking before the apex of the turn. By the
apex, you want to be in the proper gear to accelerate out of the turn.
>Many LBC drivers use H&T, for 3 reasons:
>1) It sounds impressive and pampers the synchros.
>2) They are going really hot into a corner and want to shift as fast
> as possible while feeling like Stirling Moss.
>3) They have a worn transmission with a shot synchro (mostly 2nd,
> since that one gets used most.
On the street, I do it for reason #1, and to keep in practice, because
when I autocross, I use it because of #2. ;-) It's not actually that you
shift faster, it's that you can brake later into the turn. As you approach
the turn, you are in too high a gear to be in the power band when exiting.
But you can't downshift then, or the engine will spin up to 10,000 rpm.
So, you have to brake and downshift. You can get all your braking
done and then downshift, or downshift while braking.
If you brake without downshifting, you have to allow time to downshift
before the apex; this moves your braking zone further before the turn,
and you'll be coasting while downshifting. If you H&T, you can brake
right up to the apex (trail braking), thus waiting later to start braking.
In a race, the H&T'er will slip past the non-H&T'er under braking into
the corner.
Another reason for H&T is to minimize the upset caused by downshifting.
If you don't blip the throttle to bring the engine up to the proper speed,
you'll get a big shock of engine braking as it spins up after you engage
the clutch in the lower gear. This might be okay on the street, but when
you're racing at the limits in a corner, that shock will upset the car and
most likely cause a spin.
Lastly, don't use the engine braking from downshifting to slow you down.
That's what brakes are for. And replacing the brake pads is easier and
less costly than replacing the clutch.
Have fun,
Dave Williamson (silikal@aol.com) Spits in bits
"And somebody says 'plate', or 'shrimp', or 'plate of shrimp'." - Repo Man
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