Using Brakes

[scars_of_carma]

So I noticed this forum doesn't talk a lot about driving technique? I wrote this rant earlier to answer someones question I figured I'd throw it up here just case it might help someone.

What happens when you step on the brake pedal? LOTS of things happen but the specifics don't matter. As the driver all you are concerned with is feel and control. I'll say it again, feel and control.

I could tell you the entire chain of events that happens so your foot can stop the tires but it'd probably literally take pages... so lets just concentrate on the byproducts of braking. Namely; Bite, Traction, Slip, Fade and weight-transfer.

The initial feel of the brakes is what I call bite. Bite is good. Good brakes have bite. Barqs Rootbear also has bite... Bite means you get to apply maximum braking instantly but more importantly bite = feel. If you can feel when the brakes engage and how hard they engage you can better modulate the brakes (or just use ABS) to keep them at their threshold where they do the most work.

The grip of the tires is obviously Traction. Traction is good. Good tires have traction. Traction means you can actually use your good brakes with bite but more importantly traction = control.

Loss of traction is what I call slip. Slip can be good but only when you want to slip. Slip is mostly bad. Slip is bad for traction and slip ruins bite. Slip = loss of control.

Fade is loss of friction. Loss of friction is bad. Your brakes (and your tires) depend on friction to function. Bite in your brakes (or tires) can cause fade if they are sucky brakes. Fade means you no longer feel whats happening. Fade = loss of feel.

Weight-Transfer is the result of g-loading. Sharp steering, hard braking or hard throttle can cause weight-transfer. This isn't a bad thing. Weight-transfer can improve traction and control when used properly.

Now back on topic. You are likely to understeer under braking if you initiate heavy or sharp braking after turn-in. This is a result of slip in the tires because you applying braking after the car takes a set.

However when you initiate braking before turn-in (like you're supposed too) the weight-transfer of braking puts more load on the front tires which also momentarily increases their traction. As you turn-in smoothly you ease off the brakes smoothly. The trick is to use that extra traction from the forward weight-transfer at turn-in when you need it most!

Sounds simple enough doesn't it? Now for some advanced techniques based on that principle...

Super-late-braking is basically waiting to initiate that weight-transfer for turn-in at the last possible second. That way you don't waste any speed approaching the corner. On a racetrack this is the most common means to overtake. This technique requires good bite in the brakes, mastery of threshold braking and good traction in the tires.

Trail-braking means you don't release the brakes completely until you reach the apex (roughly the middle) of the corner where you start to accelerate out of the turn. The advantage of this technique (and also the risk) is that you can brake deeper into the corner. This technique is the most difficult because it requires the most control and excellent judgement of your entry speed. You also need excellent traction and brakes that do not fade!

When you use trail-braking, you are basically controlling the foward and lateral weight-transfer like a balancing act. In addition to maintaining constant forward g-load you need to maintain constant lateral g-load as well.

Basically the reason for this is balance. Race drivers (especially circle-track guys) try and maintain constant loading of the tires via brakes, steering and throttle through a corner. If your judgement is off you spin or worse understeer up into the wall...

Think of it like this, the whole of the forward g-load (brakes) and the whole of the lateral g-load (steering) must not exceed the limit. In other words, the limit of traction cannot be multiplied. It can only be divided.

Thus, when you are entering, holding, and leaving a corner you can't stack the loads on top of eachother and expect a higher limit. You have to redistribute the loads as you are going through a corner or you will exceed the limit.

To reiterate you brake until you hit the limit of your traction before turn-in. Then you smoothly release the brakes adding steering to keep your tires loaded all the way to the apex where your lateral-g's are the highest. Then you smoothly apply throttle as you unwind the wheel to achieve the highest possible exit speed. It requires feel and control to do all these things fluidly.

[gp02a0083]

great to see some elaboration on technique here , i think we should have a stickey or a category for techniques

great write up!

[3gmodifier]

i agree with this topic being brought up. i personally use the breakless and heel to toe shift technique daily. and with this i can feel/use the moves to shift between differant feelings i get from the car, whether its under steer or over steer. or even detecting the shift between the two. i have even taught my younger bro and wife this technique. (it's funny, my best friend has a turbo H22 lude and my wife has a faster track time hahhaha)

[scars_of_carma]

i agree with this topic being brought up. i personally use the breakless and heel to toe shift technique daily.

Same here if I'm just cruising. I don't usually need to use brakes unless I'm doing spirited-driving or in traffic.

[2ndGenGuy]

Noob here. But when you're trail braking, doesn't that mean that traction you're using to brake could instead be traction that you're using to corner faster? I've always heard that you do all your braking in a straight line. But that could just be an autocross thing...

[russiankid]

Noob here. But when you're trail braking, doesn't that mean that traction you're using to brake could instead be traction that you're using to corner faster? I've always heard that you do all your braking in a straight line. But that could just be an autocross thing...

From experience, the weight transfers to the front when you're braking thus giving traction. Brake when you're just about about to turn and this will give you traction and you will take the corner well.

[scars_of_carma]

Noob here. But when you're trail braking, doesn't that mean that traction you're using to brake could instead be traction that you're using to corner faster? I've always heard that you do all your braking in a straight line. But that could just be an autocross thing...

From experience, the weight transfers to the front when you're braking thus giving traction. Brake when you're just about about to turn and this will give you traction and you will take the corner well.

Eh this is where it gets complicated... if two cars are side by side approaching a corner a good rule of tumb is he who brakes last enters the turn first. Because of this, trail braking is commonly used on the racetrack. You can use it defensively on the inside line or possibly to overtake from the outside. (Its very easy to overspeed entering a turn with trail-braking many racers end up sliding into another car or off-track with this technique. I see F1 guys do this all the time.)

Now racing-for-position aside it is generally true that you won't pick up speed through a corner doing any braking after turn-in. However in some circumstances trail-braking is the only way to carry speed through a corner or set yourself up for a proper apex. For instance on a breakaway downhill corner, decreasing-radius corner or double-apex corner its sometimes best to drag the brakes through the turn because you never really leave the turn-in phase.

Now this leads me to another way to use the brakes and that is tapping the brakes. If you are ever in a situation where you are on the verge of understeer in a turn... braking or steering harder will just make it worse. Tap the brakes and continue to modulate the steering until you feel the grip come back into the steering. You might have to tap more then once... but just tap. This is the ONLY way you can safely use brakes mid corner if you lifted off the brakes after turn-in.

Also, on a touge with lots of elevation changes (like my home course) you want to tap your brakes at a crest in the road to help the front end stay planted.

And still there is more to talk about... because there are certain techniques where you purposely brake hard after turn-in. Being that I am still learning FWD I'm not sure these apply to us... (but there was that one guy that converted his Accord to a rear-engine, rear-drive layout).

It's called a braking-drift. It can be a lot of fun but not if you are unprepared and it happens by accident. Basically you enter the corner a little quick and right after turn in you stab on the brakes. Your car should fishtail because rear brakes want to lock-up under hard braking especially when you aren't braking in a straight line. In a RWD you can just stab the gas after that and drift all the way around the turn. In a FWD you can probably still shift your car to a more favorable angle for corner exit if you kick it out a little.

Also, lets not forget compression braking. I LOVE compression braking. In a RWD the method works very well as anti-dive and it helps balance the front- to-rear brake balance. You can even induce rear-brake-bias with it... One of my favorite techniques is using a heal-toe downshift a half-second early popping the clutch to break rear traction.

If you time it right you are actually using gear-reduction braking because the tires are just loose-enough not to load the motor they just sort've drag... still spinning but slower then the car is moving. With some careful left-foot braking and throttle modulation you can even steer the rear end sort've like you would if you were trying to shift-lock drift... but instead of carrying angle all the way through the turn you just kick it out a bit while also slowing that last 5-10 mph to hit the right entry speed at the apex. If you do it right you can plant your car at the ideal angle for corner-exit.

It worked beautifully in my FC... but of course I had the beefy TII tranny, rearend, driveshaft and ACT ProLight flywheel with an HD clutch so the powertrain made it possible. Also it was much safer to spike the RPM for half a second with a rotary engine... I wouldn't try that in just any car you would probably break stuff...

Basically I used that technique the same way some use an e-brake but I prefer it because I don't trust e-brakes on 25+ year old cars honestly lol. They are unreliable and inconsistent and I'm too lazy to try and replace all the cables unless I replace them with some custom heavy-duty setup with less binding.

But ultimately, if you can achieve the fastest cornering speed by making the car stick normally on corner entry and squeezing all the lateral grip possible out of the tires around the apex there's no reason not to do it this way.

[Importordomestic]

OMG at the overflow of information. I have got to figure out how to keep you talking. I have read some of this information before but its a much easier read the way you put it.

I two have a TII FC and at the next open track day I am going to experiment with your compression brake technique. I have done it before on accident and felt the rear try wiggle but never thought of using that method to initiate turn in.

We need some ms paint thrown up that shows the various corners,and the correct line to take, brake points and acceleration points. granted its a drawing but will give a much better idea of how the techniques is applied on the track.

among techniqus, maybe adding suspension setup to show how the various chages to the suspension will change the slip angle, oversteer or understeer

for example: To reduce understeer one can run a bigger anti roll bar in the rear therefore removing understeer by promoting oversteer. This will give your car a fell of neutrality and will turn in quicker and with less oversteer.

Another way to reduce understeer is to run a negative tow on the rear wheels (again promoting oversteer) typically used for auto x as this will make the rear end very VERY unstable at high speeds.

maybe we want 2 threads? one for technique and anoter for suspension setup?

[scars_of_carma]

OMG at the overflow of information. I have got to figure out how to keep you talking. I have read some of this information before but its a much easier read the way you put it.

I two have a TII FC and at the next open track day I am going to experiment with your compression brake technique. I have done it before on accident and felt the rear try wiggle but never thought of using that method to initiate turn in.

It's risky be sure you've got open track around you if you try it. The first time I did it was by accident trying to slow the fuck down entering turn 11 at Thunderhill.

We need some ms paint thrown up that shows the various corners,and the correct line to take, brake points and acceleration points. granted its a drawing but will give a much better idea of how the techniques is applied on the track.

good idea I will try that sometime

among techniqus, maybe adding suspension setup to show how the various chages to the suspension will change the slip angle, oversteer or understeer

for example: To reduce understeer one can run a bigger anti roll bar in the rear therefore removing understeer by promoting oversteer. This will give your car a fell of neutrality and will turn in quicker and with less oversteer.

Another way to reduce understeer is to run a negative tow on the rear wheels (again promoting oversteer) typically used for auto x as this will make the rear end very VERY unstable at high speeds.

maybe we want 2 threads? one for technique and anoter for suspension setup?

I can help you on the FC I'm not the most experienced tuner with everything though...

[Importordomestic]

We need to talk about the FC - however ive got to tear the engine down and see what the damage is - lost compression on all 3 sides of the rear rotor about a month ago.

[scars_of_carma]

We need to talk about the FC - however ive got to tear the engine down and see what the damage is - lost compression on all 3 sides of the rear rotor about a month ago.

Ah bummer... right now at my house my roommate and I are planning to rebuild a buddies TII rotary engine ourselves. He's built rotary engines before I haven't. I can put you in touch with him if you like? Are you on RX7 club?

[Importordomestic]

Ah bummer... right now at my house my roommate and I are planning to rebuild a buddies TII rotary engine ourselves. He's built rotary engines before I haven't. I can put you in touch with him if you like? Are you on RX7 club?

Yes I am on RX7 club - same username give me a PM. Sure i would like to talk to anyone who has cracked that egg.

now lol back to the topic - got any more driving technique for us?

[markmdz89hatch]

ok, I think Scars gets new member MVP for this year. ...damn, I'm looking forward to some downtime so I can read through this entire thread. ...this is like candy to me, i love to read what someone writes when they actually practice what they preach instead of just going on theory alone (that's what I do for the most part sadly, due to next-to-no track time)

[JFern]

Yes! This is definitely going to come in handy when i start doing scca solo, i know a little about driving technique from my suspension and racing class, but only when it comes to RWD (ie throttle induced oversteer etc.) because thats what i had at the time, and the rest is from playing gran turismo

Lots of info to take in at once, but a good read nonetheless.... It makes me excited to get my car racing (unfortunately most of the events are in the Qualcomm stadium parking lot, but i would like to make a trip to willow springs sometime) keep it up! i might be asking for some advice soon

[scars_of_carma]

now lol back to the topic - got any more driving technique for us?

Err well I just posted another topic about springs, tires and weight-transfer lol

[gp02a0083]

rotary's are probably the easiest engine to put together IMO ive built several of them , the MAJOR issue is measuring the faces for the rotor's oil seal...ect. sadly there one kid im my town who's just flipped a blue 89 rx-7 and he previously wrecked a gen 3 rx-7 also.

but getting on topic , i also like this technical discussion

[scars_of_carma]

rotary's are probably the easiest engine to put together IMO ive built several of them , the MAJOR issue is measuring the faces for the rotor's oil seal...ect. sadly there one kid im my town who's just flipped a blue 89 rx-7 and he previously wrecked a gen 3 rx-7 also.

but getting on topic , i also like this technical discussion

I rolled my RX3 and I hate myself for it it was a classic! Sorry to hear about that kid... another FD bites the dust... *sigh* ...luckily there always seems to be enough FC's for everyone but that's the first I've ever heard of someone rolling one of those.

[Sh4d0w]

I once heard it said that a tire can only give 100% traction - if you are using 90% of that for braking, that leave 10% to steer. A very simplified explanation of why you don't turn as well when you are braking, but it makes sense to me

[scars_of_carma]

I once heard it said that a tire can only give 100% traction - if you are using 90% of that for braking, that leave 10% to steer. A very simplified explanation of why you don't turn as well when you are braking, but it makes sense to me

That is the most basic explanation for the division of traction and you can apply it to the standard driving technique... However I would clarify that you don't initiate a turn before you start braking. You can turn after you start braking and you can continue to steer while you are still braking if you have enough feel for control...

The problem with tire-traction is that its not constant. A good driver can feel the limit of a tire at any given moment but that's only half of the challenge... setup is the other.

There are many variables that affect tire-traction but first and foremost is tire selection. I don't really put much faith in advertising or comparison tests between tires because unless you have an EVO or something brand new odds are that test vehicle is nothing similar to what you are driving...

I personally never buy new tires anyway. The first and only time I spent $900 on Toyo T1-R's I destroyed them in one day at the track! (do yourself a favor and buy used slicks for track-days you will always get more smiles per dollar)

I used to be a tire-monkey at Laguna Seca mounting slicks on race cars. You'd be surprised how many slightly-bent wheels are being run on any given race weekend. Ironic isn't it? Some guys buy a new set of slicks after every session but they don't have any spare wheels... You tell them their wheel is bent thinking you are doing them a favor and they just get this pissed off look like they'd rather have not known about it in the first place. ...Funny how fragile your self-confidence is as a driver when you doubt your equipment isn't it?

Anyways a good tire is only as good as its setup. If you have bent wheels or your allignment is whack 100% isn't going to feel that great. If you take the time to properly test your tires using depth-guages and probe-type pyrometers you can figure out how to make your tires happy. If your tire is happy you are happy.

[Strugglebucket]

Good thread.

I would like to hear about any luck you've had LFB'ing an FWD. Particularly this nose-heavy accord.

[scars_of_carma]

Good thread.

I would like to hear about any luck you've had LFB'ing an FWD. Particularly this nose-heavy accord.

Ahhh Left-Foot-Braking... Yes that does require a bit of explanation. Earlier when I was talking about tapping the brakes...

...tapping the brakes. If you are ever in a situation where you are on the verge of understeer in a turn... braking or steering harder will just make it worse. Tap the brakes and continue to modulate the steering until you feel the grip come back into the steering. You might have to tap more then once... but just tap. This is the ONLY way you can safely use brakes mid corner if you lifted off the brakes after turn-in.

...I should have mentioned that it is preferable to use your left foot. Under high-lateral-load you do not want to lift off the throttle if you can help it. Think of even-throttle like a keel. You need it for better balance of the chassis. You may oversteer or even spin if you lift off the throttle abruptly.

Now tapping the brakes aside lets talk about the other ways you can use LFB.

On Corner Entry: This is the trickiest time to use LFB becuase you also need to downshift. If you don't maintain load on the engine by matching the gears to the rate of deceleration your throttle response goes to shit. It is possible to LFB and still heal-toe but it requires very skilled footwork. It is also possible to downshift without using the clutch at all but that takes lots of practice. Finally I suppose this wouldn't matter at all if you were driving an automatic or had paddle-shifters.

While Trail Braking: This is the most advantageous condition for LFB. Just as with tapping the brakes the main advantage is you don't have to lift off the throttle. In fact because you are LFB you can release the brakes and apply throttle much smoother which, in theory, means you might be able to carry even more speed through the turn.

I have not LFB a FWD

Sorry at this point I can't personally give any examples of LFB in an Accord or any FWD. Only rarely have I ever needed LFB to save my ass because I don't often drive fast enough to need it on shitty public roads.

I did use it quite a bit on the track, while rallying, or doing auto-x because I always competed with rotaries or other low-powered cars that rely on efficiency-of-momentum to maintain a quick pace. In other words the only way I could keep up was keeping the go pedal down as much as possible.

Compared to other engines its size the B20A3 has a torque-focused powerband and low redline. Also because its FWD (with an open diff) there is little gain to be had hammering on the clutch. In other words you don't want to risk wheelspin on corner exit because you will quickly kill any gains you might have made on corner-entry.

Driving Impressions of my Accord Hatch

Based on my runs so far these are the tips I've learned with my setup.

-Don't overdrive this car because you won't go any faster.
-Keep wheelspin and torque-steer to a minimum.
-Don't overrev it! Use the throttle smoothly for best accelleration. It is better to shift up early and shift down late.
-Because of my springs my car has very little forward-aft weight transfer. I don't need to worry that much about the rear drums locking up because of minimal brake dive. Even so I stay prepared for it.
-I don't need to worry about the front end getting light either. (unless I hit some harsh bumps) What do I worry about the most is maintaining lateral grip in the tires.
-I am still using OEM-spec tires but I have more negative camber up front. Unlike a performance tire I consider the turn-in limit of these OEM tires to be the actual limit. However if I drive it a certain way I can make the negative camber work to my benefit... briefly! I have to be kind of harsh with weight-transfer on the tires to make them grip well. However if I do this too long the tires start to overheat. This limits how much speed I can carry through long sweepers but it feels like a go-cart on tight corners.
-My main theory for why this car handles surprisingly good is because of its footprint. Imagine the corners of a box on the 4 contact patches of the tires. The width-to-length ratio of this box is very good for overall handling performance especially with FWD. I dunno why I know this is true its just intuition.
-Someday I will try and quantify this but in the meantime that's my opinion. It's hard to upset this cars balance. The car just feels "settled". For example it doesn't exhibit any unstable yaw movements which is more then I can say for any RWD I've previously owned but perhaps I just haven't exceeded the limit of the chassis yet... only time will tell I want better tires to find out.

I can see why people look down on Honda owners

Also, based on comparison-tests I've read in magazines recently featuring street/track driven Honda's I can see why people look down on Honda owners... it is just sad to see guys spend thousands on motor swaps, rare wheels, coilovers, aero parts, whatever... and completely overlook brake balance, chassis balance and suspension setup. Sure it looks fast but it's really more like a deathtrap. For instance in one test the guy didn't know how to mount his catchcan and it started leaking a LOT of oil under high G's. So much so it actually got on the rear tires in a turn causing instant, catastrophic oversteer. Luckily for the owner it was a professional driver behind the wheel or his Honda would have ended up crumpled against a wall...

If I had one half the build-budget of some of these "tuners" my car could drive circles around them. *sigh*

[Strugglebucket]

I think about driving technique a lot when I'm not driving and come up with all these things I want to try. And then I go to an auto-x and end up not doing any of it.

Left foot braking I'm thinking could be good in a FWD on an auto-x course. Trail braking you would be able to add throttle if the back end starts coming around too much. And on corner exit I've heard people say that keeping some drag on the brakes can help get more traction to the front drive wheels if you have an open diff. But so far I've been afraid to try any of it. I have a hard enough time just getting my left foot around the clutch pedal.

[scars_of_carma]

I think about driving technique a lot when I'm not driving and come up with all these things I want to try. And then I go to an auto-x and end up not doing any of it.

Left foot braking I'm thinking could be good in a FWD on an auto-x course. Trail braking you would be able to add throttle if the back end starts coming around too much. And on corner exit I've heard people say that keeping some drag on the brakes can help get more traction to the front drive wheels if you have an open diff. But so far I've been afraid to try any of it. I have a hard enough time just getting my left foot around the clutch pedal.

I look forward to auto-X'ing this car. Unfortunately the season ended before my hatch was ready. I guess I'll be able to give it a try in March or somethin...

I want to modify the pedals to improve feel and make footwork a little easier.