Left foot braking in an Esprit?

[neal]

Okay, let's start with a bit of a rewind.

LFB is when you stand on the accelerator with your right foot, but push the brake with your left foot so you don't accelerate. Why? Well, because rather than having the engine at a mild idle, it's trying to accelerate - HARD.

That means you eliminate turbo lag completely. Take your foot off the brake and your're on full boost immediately.

Now I must confess that as a V8 owner, lag is a minor problem. Though I have been tempted on a twisty A road, behind some Metro, to let fly! Brakes don't like it. However, since you're off them to overtake the geezer, the handling's fine!

Which brings me to by next question. How's is it like going round a corner?

Fast exit speed is essential so LFB would seem a good idea. But it seriously unbalances the car. Drive is through the rear wheels but the braking is biased towards the front wheels (since it pitches to the front, but not with LFB). So what you end up with in the rears trying to accelerate but the fronts trying to decelerate. If you're on the limit of the tyre's grip going round the corner this means you miss the corner. It might drift, understeer or oversteer, whatever...

Anyone with an SE or later had any fun with this?

[Evil_Dr_Fish]

Wow.... Fair point - Im so glad you posted this!

I have been messing with left foot braking in my day car (FWD) asI was always of the belief that the point of it was to shave speed in a corner while trying to unsettle the car as LITTLE as possible. (ie lifting off (trailing throttle oversteer) and then braking etc etc)

I didn't think of it in a rear wheel perspective... I did try it on a most very basic level in my Esprit but the pedals are SOOOO close together it was almost impossible (and the SE's pedals are even closer!)

Incidentally... Why are us earlier Turbo owners excluded from this?!

[CNH]

tapping the brakes with left foot has been a Lotus technique with many of us going back the the early Elan's and Europa's have used. If you lose engine speed with those motors (below 3500 rpm) in a turn you will take a long time to get it get up to speed.

[EspritMiltonKeynes]

It makes a nice noise - that's thrill enough for me

[TSD]

How can this work? even if your foot is on the loud pedal, if you are in gear, and braking, your revs are going down, so is your boost. wouldn't you have to disengage the clutch, and heel-toe to keep the anchors on, while keepin the turbo spooled up? This sounds foolhardy to me.

better off going in slow, downshift well before you turn in, be stable, keep revs above 3000, easy does it to the apex, start accelerating out as you unwind the steering. I don't think the turbo is very adjustable mid-corner on the accelerator. NA esprit must be much better in this respect. you don't get any suprising boost mid corner to unsettle the back.

[EspritMiltonKeynes]

Another way is to just plunge the turbo at full throtle.... there's a about a three second period whilst it's spooling up with not a lot happening and then suddenly all hell breaks loose and the car lurches away.

It's not instantanous speed but it's great when you're stuck on a single carriage road and about to overtake a line of slow moving traffic as you can use the spool up period to look around and check for gaps.

[esprithk]

I and my friends used to do this on cheap American V8 car (about US$800-1000 Oldsmobile)..

and white smoke coming out the wheels...very cool!!

and as soon as you let go the brake..the thing just jumped start..haha

another thing we did is to go forward very fast, but suddently put it in 'reverse' (only for automatic engine)

the car will do very weird thing....damn we were crazy then.

**back to your question, double-clutching is the right way in cornering, not LFB.

(actually, the LFB really can do serious damage to your drivetrain system)

Edited January 19, 2006 by esprithk

[Evil_Dr_Fish]

James - you wnat to be EXTREMELY careful doing that - see Jonathon and my sections on the Wrecked Esprits page of LEW!

[EspritMiltonKeynes]

Oh I am, I'd never dream of doing anything like that in the wet. Infact I drive like a grandpa most of the time...

[Jonathan]

Infact I drive like a grandpa most of the time...

<{POST_SNAPBACK}>

Same here, I rag the Elise something rotten becuase it's just a go-kart to me, if I stack it as long as I don't hit anyone else I'm not too bothered which is why I only go loopy on clear roads, generally late at night. The Esprit is special - however if you drive like a nancy some day somethings gonna catch up with you and you'll never know what to do - like in most people's accidents tbh....I'm convinced most accidents in supercars are caused by ill experience when something goes wrong. Although try convincing people who've never driven one of that case.

Anyways I have a clip of a V8 going around Brands Indy with a propper racing driver giving it a blast. There's clips of the pedal box, everytime the guy is standing on the brakes and sometimes angling the top of his foot onto the accelerator.

I can only speak from the Elise, I plant the brakes, down shift to increase revs and then power out of the apex usually with a bit of rear wheel screech. Must admit I dont see much point in left foot braking unless you're trying to control the car's sliding in a corner and doing lap times. On the road I see no benefit, or unless you want to replace your clutch / gearbox more often with acceleratuon whilst braking.

[Simon350S]

????????????????????

No offence guys but WTF r u talking about????

Stand on the throttle and hard on the brakes?????

Thats not whats its about atall...... Well unless you want to do a burn out whilst stationary at the lights. You'll end up snapping driveshafts and shagging your gearboxes which are obiously already very stressed components.

I've NEVER heard of anyone doing this whilst at speed or even trying to slow down slightly. Nail the throttle and stand on the brakes and you'll lock your front wheels whilst simultaniously spinning the rears. Not good in a straight line and lethal in a corner.

Left foot braking is used in motorsport to settle the car over undulating surfaces and to cut down on time off throttle when braking cause you dont have to move your foot from pedal to pedal and balancing a car on a corner if your understeering.

I can not stress enough how dangerous doing the above will be!!!!

Please dont kill yourselfs or damage your cars in the process!!!!!!

Simon

[Nigel]

As far as I am aware LFB is used to settle the suspension on your car as you enter a corner. Normally the time you spend between brake and accelerator unsettles the car.

LFB allows you to accelerate into the corner as you are coming off the brakes.

If you have never tried LFB before you will almost put yourself through the windscreen the first time you try it. It takes practice for your left foot to gain the sensitivity that is required.

Not that I'm any good at it.....

Nigel

[Evil_Dr_Fish]

As I say - I have found that in a FWD car LFB is actually a very good way fo *shaving* speed off when you are close to the edge and don't want to unsettle the car furhter by removing the throttle. (I TOTALLY accept this is different from a RWD car so don't even bother pointing that out! )

James - BOTH of our accidents were in bone dry conditions on clean, oil-free roads. SO don't fool yourself that it's about dry roads! Also Jon totally has a point when he says that if you Bampa the car and just occasionally rag it, you won't know what to do when it does misbehave.

Either bampa the car everywhere alweays and accept you won't drive it fast... or, constantly (*gradually* and carefully) explore the car's handling As soon as this weather will give me a reliable period of dry, I'm booking myself onto the 1st Lotus driver training / car control courses where they basically ask you what you want to learn and then set about teaching it to you in a safe environment

[PINGU]

Same here, I rag the Elise something rotten becuase it's just a go-kart to me, if I stack it as long as I don't hit anyone else I'm not too bothered...

I'm glad no member of my H-Team feels that way about *any* car they own... No offence but I'll make sure none of my boys are anywhere around your Elise when we meet up.

The 'definition' I'm reading here of LFB is not correct so please any inexperienced drivers reading this, ignore the above.

LFB is a racing technique used to control the dynamic balance of a car in motion to acheive a set for a change in direction. This allows an experienced driver to make the car appear to exceed its normal understeer/oversteer limit.

It is under no circumstances used as a turbo spool up method. Choosing the right gear and revs is what does that.

[Evil_Dr_Fish]

More info please?

[neal]

Woh, this thread has unexpectantly captured all!

So let me explain what my understanding of LFB is. Sure, in neutral, or with the clutch depressed you can rev to the redline easily. Maybe 5-10% throttle.

BUT that doesn't mean the airflow though the engine is anything special which has the knock on effect that the turbos don't spool up.

Now compare this with flooring the accelerator whilst standing on the brakes. Completely different - throttle is at 100%, exhaust gases are completely maxed too. So the turbo has completely spooled up. Take your foot off the brake and you'll catapult away, no lag whatsover.

Oh, Fishy, no disrespect, it's just this technique would more benefit the 'turbo heavy' cars - SE, S4,S4s. In fact your TurboEsprit would probably benefit more than my V8

As I said, the brakes obviously don't like such shenanigans, but it's the perfect way to overtake someone. Pop the brake, full boost instantly, and the car/handling is exactly like normal.

BUT what happens if you're on a track day? Obviously you want to minimise lag when exiting a corner. But LFB presents more problems. Rear wheel drive only. The rear tyres are biggger than the front. The rear pads are smaller than the front too.

So to maintain a constant speed around the corner with LFB, the rears will be trying to accelerate but the fronts will by trying to decelerate.

So if beforehand the tyres are on the limit of sideways traction, the LFB fronts may give up. Likwise the LFB rears may give up. So drifting, oversteer or understeer are all possible...

Just curious about how the Esprit respnds under these conditions,,,

Edited January 20, 2006 by neal

[Simon350S]

As I and Pingu have already stated, Left Foot Braking is not used for turbo spool up at all. Its all about balancing a car and minimising time shifting feet between pedals, hence less off throttle time.

Please do not try the suggested comments because it WILL ultimately end up an someone having a catastrophic accident.

Standing on the brakes and flooring the trottle will eventually end up in you knackering your car, brakes, driveshafts, gearbox, clutch to name but a few bits.

You will also end up one day locking your front wheels whilst simultaniously spinning the rears. On a strainght that is dangerous, on a corner it would be stupid and ultimately lethal.

How can you believe that making the front and rear of any car fight against itself in such a ferrocios way be benificial to the handling???

You do this and one day soon enough you and more importantly you beloved Esprit will be DEAD!!!!

Edited January 20, 2006 by Simon350S

[CNH]

One does not full throttle and hard brake.

I think we are talking about is going in fast under power and modulating precise braking while one is still on the throttle.

This is not about constant hard braking and full throttle at the same time.

[tonyp]

This is madness, although I can see some sort of logic if you have an autobox & want to spool up to get off the line. I can't think of a turbo / auto car you would want to try this with though (or why?)

[B33 ENN]

More info please?

<{POST_SNAPBACK}>

The Mighty PING has asked me to comment as he is busy rolling another whilst simultaneously cracking open a cold one, easier said than done when you got flippers.

Okay. Left foot braking is a technique employed by some advanced drivers to contol the direction of a car which is turning on or near the limit of adhesion. Because most average drivers don't, and should not be driving anywhere near that on public roads, it is largely a pointless and unnecessary consideration.

However, let us assume that we are on a track and can drive a car on the physical limit of the tyres.

<><, when you apply a force to a vehicle whilst it is moving, you get the concept of weight transfer. Since we are dealing with cars, we have four points of contact (tyres) with the ground split by two axles front and rear.

Lets assume our Esprit has a 40%-60% static weight distribution front-rear respectively and use a simple single-axis model where all weight changes are front to rear only, not side to side as well.

Okay, we are heading full bananas into a fast bend... The car is accelerating so the balance is more like 35%-65% at this time. The pilot (let's call him Bibbo for ease) assess his trajectory into the apex and knows he needs to decelerate to hold the line. This is because the front tyres will not hold an outward acceleration from the turn more than say 1.5g at the 35% front loading.

Bibbo has two options to take the bend:

1. The classic first principles technique is to brake, late as you like, in a straight line. Bibs retards the car to a speed that will allow the front to turn on the 1.5g line, then he applies an even throttle to maintain the speed through the apex and out. If he were going any faster, he'd experience understeer on the front axle throwing his Wedge wide of the line.

2. Another option he has is to use the front-rear weight transfers that result from acceleration and braking forces to adjust the weight distribution dynamically. He would do this to increase the load the front axle's tyres can support by increasing the downforce. So, rather than braking only in a straight line, he needs to keep the pressure on the front axle by continuing to brake into the turn.

This brings the dynamic weight distribution more towards the front axle. The result is the front axle will have more 'downforce' acting on it and the rear less. So the dynamic balance changes now from the 35%-65% to say 55%-45%.

With this new force distribution he can get the front axle to turn in at a load of say 2.5g. This means he can support a greater entry speed towards the apex. But, all of a sudden Bibs realises the rear axle, from which he has 'borrowed' some of the force, is coming loose as with only 45% loading it can't hold the 2.5g. So he needs to unload the front or he will oversteer. But, because the car is decelerating into the apex, the need to maintain 2.5g at the front is diminishing all the time, so if he relaxes the brakes, the rear axle will start to reload as he is still maintaining his throttle in readiness for apex-exit acceleration. Now the back axle will retain its grip within the maximum slip angle the tyres can support

This method of simultaneous brake/throttle is generally used in fast bends to turn the car on a line it won't hold with a static or rear biased weight distribution. However, above example is greatly simplified to explain the concept.

So why use braking while on the throttle, why not just come off the power all together to reload the front?

Well, very simply, two reasons. Firstly, by coming off the power, he can only throw a certain amount of load forwards, for more, depending on the bend, he'd need the brake anyway. Secondly, the throttle and engine braking are cruder in controlling the transfer and can create oscillations in the suspension that may continue to unsettle the car through the bend.

There are also time considerations, the time it takes to move your right foot about from one pedal to the other, in a fast bend, there may not be the time.

So, often this technique in practice is about brushing the brakes gently to acheive the set - the attitude of the car on its axles. With positive throttle, the rear suspension is being held under load, and touching the brakes will squat the front axle without changing the set at the back.

I'm not the best guy at explaining this stuff so forgive any errors (Pingu forced me) but I hope it helps.

[B33 ENN]

Now compare this with flooring the accelerator whilst standing on the brakes.

[Simon350S]

Thats about summed it up quite nicely.

Had been trying to sum it up in a one liner but it makes more sense your way!!! LOL

[WayneB]

If I remember correctly the scandinavian rally drivers invented this technique,

Eric Carlson? to help counteract the understearing handling of the front wheel drive Saabs in rallying.

It really does help promote overstear, but takes a fair bit of practise to master !

Think the turbo boost application came from Keke Rosberg qualifying the Williams turbo F1 car.

Jussi will have forgotten more about this technique than most of us will ever know

Eric Carlson and his Saab96 (he married Stirling Mosses sister, Pat) His nickname was "On the Roof" hence this pose

Edited January 20, 2006 by WayneB

[Jussi]

Wayne you are right, scandinavian rally drivers use left foot braking technic a lot. I have used it last time I had my Datsun1000 so it's been a while.

This came in -60's among finnish rally drivers. My mechanic/friend used it (and still use) when he was driving a rally.

Actually I tested this last time with my ex Citroen race car, it had pretty rear balanced brakes.

Edited January 20, 2006 by Jussi

[Jonathan]

No offence but I'll make sure none of my boys are anywhere around your Elise when we meet up.

<{POST_SNAPBACK}>

None taken really, but I certainly don't drive it anywhere near as fast / attempt the manouvers of some of the boys I've riden with do, every time I've seen them, on very busy roads. You're sounding out as if I am reckless, lol, I don't think I'd go out with that intention of risking my neck just yet - hence the bit about driving the car hard late or in the early hours (I dont think anyone of a sane mind intentionally goes out to stack their car...unless they need the cash of course ). When I say ragging it - thats within my levels of driving, which are admittedly considerably below some people's on here, although I'm quite aware of were my potential is and when / when not to exceed it.

What I do with my safety and my propperty is my consideration, however other people who share the road have no say in the matter so you have to adjust accordingly....which is why I get most of my kicks from cleared industrial estates (such as the one where I work) after 6pm when no-one is about. So if I'm out enjoying the car for what it is and what it can do and the un-expected happens (blow out, diesel patch, rabbit etc) I've already decided the acceptable risk so I'm not going to sit around for weeks on end beating my self up over it, it is just a car and a relativly cheap, easy one to fix / replace at that.