[333pg333]

Guys, I've been interested in peoples definition of this and 'Momentum Cornering'. The more experienced drivers seem to almost talk about it in hushed tones like a dying Ninja art. What are your ideas here?

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[flash]

ok - disclaimer - kids do NOT try this at home - learn to brake first, then gas - this is an advanced technique, that done incorrectly, very often leads to expensive consequences



try these:



http://en.wikipedia.org/wiki/Trailbraking

http://www.getfaster.com/Techtips/Physics23.html

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[Jim Child]

Trail braking is gradually releasing the brakes as you turn in for the corner. Beginners are taught to brake only in a straight line as turning while braking can upset the balance of the car and result in a spin. However, drivers who have developed a certain amount of sensitivity to the car's balance through experience can use trail braking to their advantage. By gradually trailing off of the brakes as you turn in for the corner and approach the apex you maintain weight on the front tires. This helps the car to rotate and get pointed toward the apex with more speed than would otherwise be attainable. It is a particularly useful technique in cars that have a tendency to understeer.



I don't think "Momentum Cornering" refers to any specific technique, at least not one that I've heard of. Obviously, the more momentum you can carry into a corner and still exit successfully the faster you will go. Beginners tend to carry too much momentum into corners, get the car all upset, recover and exit the corner slowly. They are generally instructed on the slow in, fast out approach, as a fast exit is more important because exit speed is carried all the way to the next corner. Once a driver has mastered the fast exit then they can work on developing a fast in, fast out approach, maintaining as much momentum entering the corner as possible. In the end going faster is all about less brake and more gas. When I want to go faster, I look for corners where I can use less brake pressure, and come off of the brake and get back on the throttle sooner.



Hope that helps.

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[94SilverCab]

Could we add "Throttle Steering" to this seminar please.



Thanks,



Jay

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[Jim Child]

[quote name='94SilverCab' date='Sep 30 2006, 04:16 PM']Could we add "Throttle Steering" to this seminar please.



[right][post="26531"]<{POST_SNAPBACK}>[/post][/right][/quote]



You can use the throttle to reduce the grip of the rear tires causing the car to rotate. There are two ways to do this. By lifting off of the throttle in a corner you will transfer weight off of the rear tires and onto the front tires. This reduces the rear tires' grip and rotates the car. This must be done with care as lifting off the throttle too much, or too abruptly will cause the car to spin. 911s are famously sensitive to this technique.



The second way to reduce the rear tires' grip is to add throttle in a corner. A tire only has a certain amount of grip. You can use it for cornering and/or acceleration. If your car has enough torque you can add throttle in a corner, accelerating the rear tires thus reducing the amount of grip available for cornering. This causes the car to rotate. The more power the car has the easier it is to use this technique.

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[Eric_K]

What Jim said is of course right on. Trail braking allows you brake less initially and carry more speed into the corner because you are still braking after turn in. It can take a bit to master because there is a fine line between braking too much and over slowing the car and not braking enough and running out of options. It can be really helpful in pulling off a pass too. It also makes for a smooth transition which helps because what you really want to be doing is getting back on the throttle as soon as you can.

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[333pg333]

Ok so check out the guy on the cart: http://www.karting1.co.uk/braking-karting.htm

he is doing what I would refer to as a 4 wheel drift and by doing this he points his cart at the apex with the drift rather than stop and turn at it. Now you can do this merely with power and balancing it on the throttle with a slight bit of opp lock. I can imagine also doing this with left foot braking which gives a similar outcome by releasing weight off the rears and turning in with the brakes being applied more to the front.

I found that my car with it's Mo30 suspension wants to break the rears by losing traction due to the heavy l.f.b. I am hoping that when I install the new system in this week that the attitude will be much better due to the much stiffer setup.

I think what is difficult to conceptualize about trail braking is that you are actually braking through parts of the corner that ordinarily you would be starting to get on the gas due to having done all your braking already a la the 'European Style' aforementioned.

The term 'Momentum Cornering' was brought up by someone else, maybe on a different site, in reference to him having a 951 and his friend having a 944. He found that he would rush up to corners, brake late, and use the power of the car to drive away while his mate in the n/a didn't have the power to do this so he tried to drive through the corner at a more constant speed therefore not having to give up too much of it and having some decent exit speed. If that makes sense.

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[flash]

it is a very effective technique, but the only thing that separates it from a 4 wheel skid into a wall is years of track driving - done correctly, it can make you very fast - done incorrectly, it can make you very sorry - it is very much "driving on the edge"



anybody reading all of this, and considering trying this, PLEASE don't try it out on your favorite canyon - take some laps with an instructor showing you how first

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[Charles Geer]

For my 2 cents (Jim Great Explanation).



I notice that the 968 can handle more momentum than the cup cars I have driven. If you set your 968 up right you should be able to dump a lot of speed into the tighter turns (THIS MAY BE WHAT YOU MEAN BY MOMENTUM CORNERING) the car may temporarily squeal the tires (Power drifting towards the apex of your favorite bus stop checane) if done properly you should be able to get on the throttle earlier than your opponents who's cars could not handle high levels of aggression. You don't want the car to fishtail but you want the car to gently compose itself towards "trackout" after you have cleared the apex...under full throttle.



By yourself a good insurance policy before trying.

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[Dave]

Charles - That seems to be what I'm discovering in my 968 now. Seems set-up pretty well (finally) and really seems to enjoy carrying tons of speed in under braking in slower turns (Road America T5, T8, T12). Made for HUGE improvement in my lap times there and much help in passing.



Jim's explanation is spot on. This is a refreshing thread with good insight from some of the really fast guys in 968's.

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[chris]

Great thread!



I'll add one tip: one way to get a feel for the concept of a technique, would be to play something like GT4 (I'm serious). That way, you can start to understand how the technique is applied. Obviously, applying it to the real world is a different story, but it honestly does help.

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[ether_joe]

sounds like for us rookie drivers an Autocross course would be optimal to try on - worst case scenario you plow some cones. . .

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[mike]

We all trail brake every time that we come to a red light when we ease up on the pedal as we get close to stopping so that we don't have a jerky stop. Same principle without the turning.



Regarding trying this on an autocross course. I can remember going to an autocross where one of my competitors with an RS America setup nearly identical to mine was running much quicker than me. I felt like I was driving well that day but I could not equal his times. So I asked him what his secret was. He told me that he was left foot braking through the long slalom on the course which kept the front end down and provided much better handling. It is something that I have played with but find that it takes a lot of practice to develop a feel for it and it doesn't feel natural with a manual transmission. It is much easier to do in my wife's automatic Touareg.



mike

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[cooz]

having driven Mid-Ohio for the first time recently during the Nasa Championships, i believe one key to drive that course faster (besides finding my missing hp) would be to use left foot trail-braking in many/most turns except perhaps only 2.



is that right Jim (Child)?



regards,

norm mandell

white 968

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[333pg333]

I think the most foreign aspect of trail braking is that you are on the brakes and off the gas into part of the corner when traditionally you have already braked and are now feathering the throttle waiting to get back on the gas. It seems like you are scrubbing off too much speed and this is the hard part to get your head around. Alternatively you can go in too hot as you need to brake later for t-braking, and over cook, resulting in at best a spin - at worst....well, much worse!?! In Australia there are very few tracks and even less schools or tuition. We don't have access to all the facilities that you guys have, let alone how much less you pay for everything (aarrrgggghhhhh it's expensive to do Porsche stuff here!). Anyway I found another interesting site with an explanation of trail braking. I agree with Jim's assertion of car dynamics, but this in itself doesn't define t-braking as such: http://virtualracersedge.com/trail_braking.htm

So if we are basically using our brakes to brake, our steering wheel to steer, and our gears to be in the best torque range, at what point during this 'later on the brakes-while you turn in-get the front in and the rear out-type of technique' do you downshift? As we are not meant to downshift for the purpose of slowing the car ( a point which I think is debatable as at the very least the process of being in a lower gear by definition means we are slowing whether it's for that purpose or not) where do we find time to downshift in this condensed attack on the corner? OK so do we get on the brakes later and initially harder, then turn while still on the brakes but possibly lessening the modulation as you progress through the corner, then heel and toe as an incidental act to provide us with the best gearing with which to drive out of said corner? In which case where does left foot braking come in?

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[cooz]

downshift at the end of your primary braking period while your front wheels are still pointed straight just before your turn in...then trail-brake into turn and transition back onto throttle.



my 2 cents

norm mandell

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[333pg333]

I still can't see it if that's the case because as I downshift at my initial braking point, I'm heel and toeing which is washing off a lot of speed, then you're saying that you left foot trail brake through a lot of turns? So at some point you are having to swap feet and brake at the same time? Also as you wash off speed while heel and toeing I find it hard to visualize not washing off too much as to make the braking through the corner sort of redundant. If you see what I mean? I thought in fact I had been braking too late in some corners as I was getting the car unsettled sometimes and it was causing me to lose too much momentum getting the car back into the apex and out of the corner. It seems to me that I have to leave it even later so that braking through the corners is of any use? I still sit here somewhat confused. <img src="/forum/images/smilies/968/blink.gif" class="smilie" alt="" /> The hardest thing is not being able to practice this.

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[flash]

lol - yup, except maybe for actually practicing it and finding out the hard way that you goofed and stuffed a wall - that's why most instructors don't teach it, and it is really thought of as an advanced technique - it takes LOTS of practice to get right, and not something to figure out with other cars around you - pretty much need to work that one out in solo track time, which is its own kind of fun anyway



on the shifting thing, since the whole idea is that you start braking later, and then continue braking into the corner, gradually releasing through the corner, shifting during this process is a whole extra bit of fun you get to learn - i've been playing with this off and on for 20 years, and i still don't have it right



need more track time - yeah yeah - that's it - lol



have fun and good luck

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[Jim Child]

[quote name='333pg333' date='Oct 3 2006, 05:47 PM']I still can't see it if that's the case because as I downshift at my initial braking point, I'm heel and toeing which is washing off a lot of speed, then you're saying that you left foot trail brake through a lot of turns? So at some point you are having to swap feet and brake at the same time?

[right][post="26596"]<{POST_SNAPBACK}>[/post][/right][/quote]



I LFB in all corners that don't require a downshift. For those corners that require a downshift I complete a H&T downshift as quickly as possible while still traveling in a straight line. I then finish the reminder of the braking with the right foot. I never swap feet under braking, and wouldn't advise it.



Any engine braking is incidental to downshifting. I try to make the downshift as transparent as possible, controlling the balance of the car with the brake and then transition to the throttle. You definitely don't want to be completing your downshift after turn in as an unsmooth downshift can upset the car significantly.



Regarding Mid Ohio, I usually trailbrake in all the braking zones. Usually it’s a little bit in the fast corners, and a lot in the slower corners.

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[333pg333]

So Jim would you say as a generalisation that one t-brakes more in slower corners? I am thinking of one hairpin in particular on our best course Eastern Creek:

http://www.eastern-creek-raceway.com/ If you look at turn 8 (based on turn 1 being the furthest left on the picture) which is the 2nd hairpin on the course, you are travelling pretty fast in 4th, downhill and a little off camber which is exacerbated by the longish left hand turn before it pushing you out to the right. The hairpin comes up at you pretty fast and it's pretty hard to do your H&T down through the gears and then left foot t-b all while getting the late apex just right. Maybe have to get off gas slightly earlier, do downshifts, and then change over to your left foot to t-b around corner. This happens pretty quickly as you can imagine. I've got a track day this Sunday which is mainly timed sessions so no real dogfighting, I may try it on a few of the corners at a bit slower speed first. The only problem I see in trying at a slower speed is that it feels like you're scrubbing off way too much speed and defeats the purpose but I guess it's just a familiarity exercise?

It just occurred to me that as I have a 951 which as you guys may or may not know has a distinct off boost lag and lack of torque combined with pretty long gearing. I reckon my car could easily do 270kph (indicated) so maybe your 968's 6 speeders don't have to go through the same amount of gearchanges and have more torque down low? For us when racing you really have to be in the correct gear/tq range or you just bog down badly. This can be remedied of course with various mods but atm my gearing and turbo are stock 250hp.

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