Left foot braking

What would you guys say the purpose of it being?

I'd say it'd be if you started to plow through a corner, while still having the gas depressed, it'd be an advanced method to rotate the rear to come out of under steer.

I though it was used mostly in Fwd cars to help keep the car as neutral as possible when taking hard corners. very tricky to do if you don't do it often because hitting the brakes with your left will feel weird and in turn the pressure applied will not be spot on.

Lonewolfjulez wrote:

I though it was used mostly in Fwd cars to help keep the car as neutral as possible when taking hard corners. very tricky to do if you don't do it often because hitting the brakes with your left will feel weird and in turn the pressure applied will not be spot on.

I thought you so but I've noticed in Hot Version drivers doing this also in AWD and some RWD cars as well.

Yeah, just braking with a left foot... my steering wheel has busted my lip before.

So I am going to put my nerd hat on for a second...

The reason for left foot braking in FWD and AWD is to make the front end dive so that more weight will be on the front wheels in a corner situation. Then you want to roll onto the gas while trail braking on the left foot to keep the weight toward the front till you apex.

The reason for this is because of lack of caster, without a good amount of positive caster your car will change level ALOT when brakes are applied and throttle is given. This is the reason for the anti-lift kits. Allows you to make the car to dive, but not to much. Then once throttle is applied the front of the car will stay down giving your front end more bite.

Otherwise its just another school of driving. Its not needed, but can be helpful.

I've only really focused on this or used it in full circle situations, like a roundabout or such that I can get dizzy in.

There are lots of circumstances or situations that call for left-foot braking. Primarily (in my opinion) to help counteract understeer (as the author of the thread said), or to prevent lift-off oversteer.

my circumstance is that I drive a go cart for a daily so left braking is the norm

It does two things help balance the car and shave a fraction off of your throttle response. Both make you just a little faster.

Back when I had my Prelude, with the stock suspension setup, I was using left foot braking most of the time, esp. around sweepers. The car had a bit of understeer, which was apparent when trying to throttle through most long turns. Instead of letting off the throttle and getting the car pivot (which works well in the Miata), left foot braking was a better way of balancing the car in this case without letting off the throttle, and helping to stay in the powerband longer. I don't know much about the theory behind why this worked so well, but all I know is that it worked!

Why 4th gen preludes behave the way they do is the suspension geometry is setup so when the rear is compressed it goes into a toe out condition.

The reason why lfb is super effective in a prelude is that the 4wheel brake system acts on all 4 wheels but the rear axle has low rotational mass compared to the front so when you gently lfb while under throttle it shifts the weight forward (this turns the car into a point and squirt machine). The stock suspension in a prelude makes it seem like its a rwd muscle car causing the front end to lift under throttle.

I had a 3rd gen without the 4-wheel steering for the record

500KEG8 wrote:

Back when I had my Prelude, with the stock suspension setup, I was using left foot braking most of the time, esp. around sweepers. The car had a bit of understeer, which was apparent when trying to throttle through most long turns. Instead of letting off the throttle and getting the car pivot (which works well in the Miata), left foot braking was a better way of balancing the car in this case without letting off the throttle, and helping to stay in the powerband longer. I don't know much about the theory behind why this worked so well, but all I know is that it worked!

I think you explained the theory pretty much right there. Good post! I remember driving my underpowered Honda's the same way. Never Lift! ...add brake as required.

It works great for building load during off throttle situations, crucial to driving a turbo car completely flat out. I've never felt it necessary, but tightening up a line mid corner I use it whenever the front wheels are under power. When it's only the rear I will usually lift or breath the throttle for a moment to transfer the weight, basically throttle steer instead.

I hate understeer of any kind so a lot of my cars run no fsb, and usually a slight rate increase. Not sure how I am going to approach this MacPhailson car I have now.

Sisukas wrote:

I hate understeer of any kind so a lot of my cars run no fsb, and usually a slight rate increase. Not sure how I am going to approach this MacPhailson car I have now.

I wouldn't hate on the MacPherson too much... having driven several of both types I think the MacPherson has an edge in outright feel for tire grip (if not necessarily maximizing that grip).

I like to run stiffer AND shorter springs on the macphersons (limiting suspension travel somewhat to minimize the drawbacks of the camber-gain through body-roll).

My fastest build was an FC RX7, setup with a lot of push because of its fat swaybars, stiff bushings and short springs. The macphersons let me feel out the available grip for corner entry very well just by 'sawing' on the wheel.

Because of its stiffness though It HAD to have good tires or it would understeer like a pig.

The ideal mcphearson set up has a camber rate that compensates for body roll. So when you are cornering the car rolls down towards the outside so the camber increases from compression to compensate. Getting this to match is a job for differential equations or trial and error. This is where you would use eliptical/crash bolts, Roll center adjusters, adjustable top hats, and custom Lower control arms.

MidnightblueMR2 wrote:

The ideal mcphearson set up has a camber rate that compensates for body roll. So when you are cornering the car rolls down towards the outside so the camber increases from compression to compensate. Getting this to match is a job for differential equations or trial and error. This is where you would use eliptical/crash bolts, Roll center adjusters, adjustable top hats, and custom Lower control arms.

Err... well the factory does a pretty decent job of giving the macpherson some negative camber in a roll... up to a point. That's why I say its suspension travel has to be limited so it doesn't roll beyond that point into the positive-camber-gain zone.

My Mazda RX3 rally car had issues in this regard... which is why I lowered it and shortened the suspension travel before I started driving it on the street.