Question...

[Kaldar142]

Over the weekend i tracked my Z06 at summit point on the Shenandoah circuit.

Car was great, but had a few questions...

My instructor kept telling me to not down shift until the absolute end of the braking zone, IE right before you turn in.

I had never done that before but he insisted that i must do it that way, how do you guys feel about that? He said at higher speeds it will make more sense, but i don't really see how it would matter if i'm still applying the same amount of braking force the entire time while heel/toe downshifting

Second, he kept on telling me to brake earlier...?? He normally drives an MR2 so hes not used to 500+hp so maybe he was just nervous but he had me braking extremely early to the point where i would almost coast a little before going into the turn as opposed to braking hard prior to the turn and then turning in.

Basically, he had me brake early then get on the gas and go through the corner... thoughts / opinions?

This driving style was much different than what i had normally been doing with other instructors.

I didn't really question him at the time because...well hes an instructor and knows more than me, lol''

-Joey

 

[Philostang]

Hey Joey,

He may have been trying instill a "preventative" mindset on both accounts (though for very different concerns).

1. Downshift Later: When you go into a lower gear (at any given speed) your engine must be revving higher (to maintain that road speed). That's a given, and that's why we blip the throttle when we heel-toe downshift. However, if your road speed is too high and you pop it into a lower gear, you'll end up over-revving the engine. Once you pop the clutch, there's a direct link between your tires (thus, to the road speed you're at) and your engine. This will "pull" your engine up to the required rpm to match that road speed regardless of any (electronic) rev limiter you have. This is what Carrol Smith affectionately called "the rod stretcher" (Drive to Win, p. 2-42) it's a great way to blow up an engine. My guess is that your instructor was just trying to get you in the habit of downshifting at a safer road speed.

2. Braking earlier isn't such a terrible thing; and in fact I was encouraged (sort of) by some of the instructors at Bondurant. Bonzai braking is always bad (this is different from properly executed "late braking" but many folks don't know the difference and think "Late is Great" - which frequently is NOT the case). You upset the car far too much and also run a much greater risk of oversteering the car if you are forced to begin your turn while under very heavy braking. So some endorse braking a bit earlier to get the car under control and at the proper speed for the corner. Once you have that down, you can begin to dial back the braking point or brake pressure. The bottom line is that maximum speed through the corner is faster than maximum deceleration at any given point in the turn. So you prioritize the speed by safely finding it, then begin tweaking your braking point, pedal modulation, etc.

(Note: The exact lesson at Bondurant wasn't exactly "brake early," it was "find a fixed spot to begin braking and stick with it; consistency is far more important, for it serves as the basis for any form of experimentation with other parameters of how you go through the corner.")

Finally, that instructor may also simply have had a more conservative approach. There are decent reasons for advocating what he was pitching, but that doesn't necessarily mean those were his reasons for pitching them.

Best,
-j

 

[SoundGuyDave]

John is 100% right, and I advocate making the shift at the end of the braking zone as well, much for the same reasons. I haven't heard "rod stretcher" before, but the term "money shift" means much the same...

A few things for thought and general discussion: When you blow a heel/toe downshift, you seriously unsettle the rear, which can easily cause a spin. Personally, I would rather be a passenger in a car doing 60mph, and not 140mph... Recovery from a botched downshift is also much more survivable at lower speeds (end of the braking zone), since you can just recover the car, get it straight, and keep braking right to the very edge of the track, and THEN make a turn-in, at a very low speed. If it happens at higher speeds, even though you have more distance to make the recovery and start dumping speed again, you're starting at such a high speed, you may not have the time to recover and then brake without going "off."

Second, his comment about it all making sense at higher speeds relates directly to what John was saying, in that if you shift too early, you're going to put a hurting on the motor and your pocketbook. I always push consistency, actually insisting on the student either brushing the brake pedal or saying "brake" during the cooldown lap, just to implant the fact that he NEEDS to hit the whoa pedal there... He may well have been trying to "program" you to shift at a certain point, anticipating higher speeds later that would REQUIRE the shift be done at that point.

BRAKE--SHIFT--GAS--TURN. That's the order of things taught in the lower rungs, and they're there for a reason. Do your braking in a straight line, get the downshift done, get back on the throttle to maintain speed (maintenance throttle), THEN turn in. Any silliness will be well behind you, and there is a very decent traction budget reserve in the event that you go in a little hot. As you pick up the pace, you can heel/toe downshift at the end of the braking zone, then get on the gas, then turn-in. As you progress in control skills (and your nutsack begins to grow), you can extend the braking zone past the turn-in point (trail-braking), but you had BEST be prepared to get on the throttle quickly, or you will wind up looping the car.

There are a few other factors at play here, as well, ones that I can't say for sure were applicable without having been in the right seat, but I think that you'll find that as the speeds come up, you'll need to turn in sooner. Also, as your skills come up, and you start thinking about trail-braking to rotate the car, you'll need to turn in earlier for that as well. In general momentum cars run close to a geometric-apex line since the don't have the power to accelerate out of the corner. Power cars run a late-apex line to take advantage of the power. There comes a point, though, when your head actually starts to wrap around the concept that ALL cars are momentum cars, to some extent, and you use different techniques to start getting back towards the geometric line, which allows the highest possible corner-entry speed.

 

[ArizonaGT]

Any chance your instructor's name was Joe or Bill?

 

[Vapour Trails]

The whole sequence of events as you enter a corner still gives me a lot of issues.

I had one instructor that basically told me bliping the throttle was unnecessary. He told me to engage the lower gear while I was still braking. I told him I can't - I'm still on the brake, I can't blip (can't heel/toe to save my life). He said, doesn't matter, I was like LOL WUT? Obviously doing it that way will upset the car at critical time.

Anyway, he distracted me from the way I normally do things to the point where I went off the same corner twice (luckily in that corner, beyond the track, the entire area is paved) simply because I was more concerned with executing the downshift than braking because I don't have the skills to do both at once.

Basically, the only way I can corner is by doing all the braking first, then executing the down shift while momentarily coasting prior to having to turn-in. Surely not the fastest way, but at least I can just concentrate at one thing at a time.

Question: If you need to scrub off a lot of speed going into a corner, when do you depress the clutch relative to the braking? Are you disengaging when you begin braking, somewhere in the middle, or right at the end?

Also, how are you executing the heel/toe? Are you literally using your heel and toe, or are you just rolling the side of your right foot over to the gas. I cannot fathom how anyone literally uses their toe on the brake and heel on that gas with the pedal placement on these cars.

 

[Random Asshole]

Wtf does that instructor know, he drives an mr2. Like the guys above said, he was probably trying to get you into a rhythm so you can concentrate on smoothness while keeping things safe. It's the same tried and true "in slow, out fast, then adjust from there" mentality everyone uses to instruct.

Not only does my size thirteen shoe makes "side stepping" the gas pedal difficult, it's damn near dangerous if something goes wrong when I'm behind someone entering a corner. I never blip the throttle. I use the engine as a brake, but after 80% percent of my braking is done. Rev matching would be nice, but it sure isn't holding me back considerably. I've considered mounting a screw in pedal/cover plate on the gas angled towards the brake pedal to make things easier, but like I said, I don't feel rev matching is holding me back yet. There's other easier places to improve on first at the enthusiast level IMO.

And besides, rod stretching is a good thing in my book. It has been proven to increase compression ratio, therefore, giving you free horsepower...

 

[Sleeper_08]

I can't heel and toe either but do blip the throttle,especially going into second. If I don't match the revs and then let the clutch out too fast the rear wheels tend to lock up which can get exciting

 

[Vapour Trails]

Ok, so not rev-matching isn't pure lunacy?

 

[Random Asshole]

Ok, so not rev-matching isn't pure lunacy?

No it's for the very talented/skilled. Left foot braking is lunacy. (see 2:13)

 

[Kaldar142]

i do heel/toe (not really heel/toe, more like half my foot on the brake and slightly roll over to the gas) pretty well i'd say, i use it in daily driving which helps me become pretty good at it.

I'm going back again on June 19th-20th, can't wait! I'm trying to find an event in between that maybe i can sneak in.

After reading what you guys said it definitely makes much more sense now, thanks!!

 

[Philostang]

Wow! I left foot brake when I can (i.e. when I don't have to downshift), but that guy at 2:13 is a freak of nature. That is really nuts...

Anywho...as Joey said, I practice my heel/toe and left foot braking on the street to get practice. Aside from the basic muscle memory training, I find it also helps your mindset. If you grow confident enough to left foot brake in heavy traffic when near-emergency type stops are frequently done, you don't sweat it at all on the track. I did work my way up to that point though...spent at least a month doing it every day, but only with TONS of room ahead of me.

Also, +1 on rolling the foot. It's more like the toe on the brake, roll over the throttle with the middle of the outside of the foot, and roll back. Everyone's feet, legs, and hips like to move a bit differently, so really you just find something that feels "natural" to you (sort of).

If you don't want to risk practicing in traffic or on your everyday driving, you could always find a large parking lot and practice. Just to a series of straight line near-stops, back and forth, practicing your heel/toe technique. Drive up to 40-60 mph, brake, heel/toe downshift, and drive on. Turn around and repeat (until the cops show up).

Best,
-j

 

[SoundGuyDave]

Okay, let me enter the frey.... First, I don't left-foot brake, mostly because my left foot is STUPID, and only knows how to work the clutch... Seriously, though, learning to heel/toe isn't that hard, and it does pay dividends in the long run on track. The BEST way (absent the parking-lot/cops thing!) to learn it is on the highway, under nice, steady cruise conditions. Start by just going back and forth between fourth and fifth at a nominal speed, say 60mph, and concentrate on keeping your speed steady as you do the change. Once you get comfortable with that, start picking different speeds (50mph, or 70mph for example) to get used to judging the engine RPM needed for the lower gear. THEN, and ONLY then, start dragging the brake just a bit while you do the change, and focus on not "jerking" the car with the brake as you blip the gas. Once you get comfortable with that, start doing heel/toe downshifts as you approach exit ramps. If you blow it, no big deal, since you have LOTS of room to get back on the brake...

After a while, it'll become second-nature, and you'll start doing it ALL the time.

Now, as to why: On-track, we're all shooting for using the last bit of our traction budget, at all times possible. That means that you're threshold braking heading towards corner-entry. IF you clutch in early to get to the lower gear, and then sloowwwllllyyyy let the clutch out (slipping the engine up to speed) you will have done two things: First, you'll momentarily take some load off the fronts as you clutch in (sudden cessation of engine braking acts like easing off the brakes), and then you'll take load off the rears as you start to slip the clutch (weight transfer) at the same time that you're increasing the net braking action in back. If you're close to the limit, that could be enough to unsettle the rear, and possibly cause a spin. It's also happening earlier in the braking zone, at higher speed. Properly done, the heel/toe dance should occur late in the braking zone, as you're already starting to ease off the braking pressure. That means less impact on the braking and balance, and it all happens at a lower speed. It's also a LOT quicker, since you're on and off the clutch about as fast as a normal upshift.

I do heel/toe in the pretty traditional manner, keeping the left edge of the ball of my foot on the brake pedal, and pivoting the heel over to stab the gas pedal. I do okay at it, but I could be better. I have noticed, however, that my lap times have fallen as a result of increasing heel/toe skill... With the car stable (not dancing around, unloaded!), you can get back on the gas earlier, and harder, and more predictably...