Left foot braking for the road with a manual transmission

[thewarlock]

Hustle_ said:

brisel said:

Quicker braking reaction in extremis

You'll be hoping that you don't need to come to a complete stop, as you'll have no feet left to get the clutch down.

In an emergency, just pull it out of gear. Or stall it.

[520TORQUES]

pethedxx said:

520TORQUES said:

pethedxx said:

Nobody has mentioned the benefit of keeping a turbo spooled up while LFB. Keeping the turbo on boost, especially in AWD and FWD cars while braking is a huge benefit in rallying. Why anyone would want to LFB on the road I don't really understand though but each to their own

Your brakes don't work properly if you are creating boost whilst braking in a servo assisted car, it relies on the vacuum in the inlet plenum to power the servo boost. To use ALS or on boost braking, you need a none servo assist brake system, rally cars don't use a servo, production based rally cars such as GroupN remove the servo.

You dont use the throttle pedal to generate boost during braking, that is done via automatic strategies which alter the engine control to generate boost without generating any torque. If you used a throttle based boost build strategy you would be fighting engine torque with the brakes. The benefit of LFB in that application is speed of change of input and the ability to have some crossover to improve traction and balance.

So you're saying no-one's ever left foot braked a turbo car? I must have been imagining it all these years

The mind boggles.

[waremark]

520TORQUES said:

Your brakes don't work properly if you are creating boost whilst braking in a servo assisted car,

So why doesn't heel and toe interfere with braking force?

[Hustle_]

waremark said:

520TORQUES said:

Your brakes don't work properly if you are creating boost whilst braking in a servo assisted car,

So why doesn't heel and toe interfere with braking force?

Because clutch

[Haltamer]

pethedxx said:

520TORQUES said:

pethedxx said:

Nobody has mentioned the benefit of keeping a turbo spooled up while LFB. Keeping the turbo on boost

Your brakes don't work properly if you are creating boost whilst braking in a servo assisted car, it relies on the vacuum.

So you're saying no-one's ever left foot braked a turbo car? I must have been imagining it all these years

"Brake Boosting" (i.e. Hold it on the brakes whilst winding up) is huge in American highway pissing contests, and I've seen it done elsewhere too - Vaccum pump seems to be fairly normal fitment and would facilitate normal brakebooster (As in servoing) operation?

[520TORQUES]

waremark said:

520TORQUES said:

Your brakes don't work properly if you are creating boost whilst braking in a servo assisted car,

So why doesn't heel and toe interfere with braking force?

Because when healing and toeing you hit the brakes first, whilst the engine is producing a vacuum as you shut the throttle, and the blips from rolling your right foot on the throttle during downshifts does not create boost.

On a few occasions when competing, I've beaten the servo vacuum on initial brake application even with right foot braking, with the resultant loss of brake servo assist, you then have to press much harder on the pedal. You want to avoid that inconsistency, which is why group N cars remove the servo and replace it with a solid rod. With ALS it's essential to remove the servo as you are generating boost even off throttle.

[520TORQUES]

Haltamer said:

"Brake Boosting" (i.e. Hold it on the brakes whilst winding up) is huge in American highway pissing contests, and I've seen it done elsewhere too - Vaccum pump seems to be fairly normal fitment and would facilitate normal brakebooster (As in servoing) operation?

Putting the engine under load on a turbo engine will produce boost, that's all they are doing there. A better method is to use rolling anti lag, that doesn't put any load into the brakes or transmition whilst building boost.

[kitcat7]

Having left braked for many years, both on track and on the road, I felt that I was completely natural with either foot, when driving manual and auto, which I do on a regular basis. When taking the auto, I always used to LFB and occasionally when pressing on in a manual Seven. I did this for many years and thought I was quite happy with the whole thing, until one day, whilst driving the auto I had to brake very very suddenly when someone pulled out in front of me. Yes I stopped in time using RFB, but only after what seemed like seconds, but must only have been a fraction of second, whilst my brain decided which foot I should move. It really frightened me and ever since I have stuck religiously to RFB in both manual and auto when on the road, with the occasional use of LFB to set up the car when pressing on, but never for normal braking, I have a dedicated foot for that now and I think that is the point for the average driver - when a real emergency occurs there should be an instant and automatic reaction.

[Steve H]

Unfortunately while there are certain disciplines where LFB can be beneficial and there are individuals that do use it very effectively, in most cases it is anything but effective.

The majority of drivers that try it when I sit with them on track as an instructor tend to use the brake pedal too often and at the wrong moments and in most cases can rarely brake as accurately as with their right foot.

Other than having your left foot constantly hovering over the brake pedal in case of emergency I cannot imagine many benefits on the road and even then it would be a rare driver that would actually be safer by doing it.

[mko9]

It would be very tiresome to have your left foot hovering over the brake for any extended period of time, at which point how is lifting your left foot off the floor to engage the brake any faster than lifting your right foot of the gas pedal to engage the brake?

[zzrman]

Reminds me of the story told to me by a well known race car driver and trainer. One of his pupils asked him “should I try some of this left foot braking I keep hearing about” to which he replied “I would wait until you have mastered the right foot braking first”