Originally posted by ODC:


Is the concept of engine braking lost on you?

Simply put, you are supposed to downshift and keep your car in the proper gear at all times. That is the correct and safest way to drive.

That being said, I always slow down in neutral.



I have never had trouble with the concept of engine braking. I've used it moderately on every stick'd car I've had and one of the main reasons I despise driving a slushbox.

If you would review my first post in more detail, my contention is with the following instances of bad physics:

Originally posted by ODC:
...if you're racing or need to slow down really quickly, you should brake + downshift at the shift points. The car will slow down much faster.


and

Originally posted by ODC:
your stopping distance increases when you are not in gear



Two primary forces act to slow a car: Aerodynamic drag and tractive effort at the tire contact patches. For a car to slow any more quickly one of these forces must be tinkered with.

Let's agree that aerodynamic drag is not a function of which gear the car is in, only speed, geometry, and air density.

Tractive effort is the manifestation of all forms of active or passive mechanical drag in the driveline and rolling stock (engine braking, bearing friction, tire compression, active disc braking, et. al.). All resistive forces that engine braking provides must be transmitted through the contact patch in order to slow the vehicle. Further, considering the fact that almost all braking systems are limited by the available traction at the road, if one needs to 'slow down quickly' as you suggest, he will be using his active braking system to this traction limitation. Any additional mechanical drag provided by engine braking will provide no benefit if the active brakes have reached the limit of traction, as they are designed to do. The vehicle will slow more quickly with engine braking if, and only if, the active brakes are not at the traction limit -- but that is not scenario you have been promoting.

A second-order variable related to engine braking that might could provide some small benefit is weight transfer (increasing the area and normal force at the contact patch). The counterpoint there is that any weight transfer provided over what's already present due to maximum active braking would, again, have to be provided by a force acting at the contact patch. If there is no more traction available, no weight transfer will occur.

B. Riley Melbourne, FL '01 Camry LE V6/5-spd Was: '00 Black/Tan SVT Contour #560 - Sold 3/26/03 Before that: '95 Champ/Blue Contour GL V6 ATX