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02-16-2009, 08:50 PM | #1 |
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advantages of heel-toe downshifting...???
So i'm going to be getting into AutoX in the spring once i get my car, and i'm curious about heel-toe downshifting. I know this is a more advanced technique, so i want to practice on my crappy VW jetta before I even get my 128i, so all the times I mess up aren't on my new clutch/transmission. I've been doing some reading up on the technique, but I don't quite understand how it is more adventageous than just downshifiting & engine braking before entering a corner. The articles I've read lead me to believe the big advantage of proper heel-toe downshifting is that you keep the RPMs at the correct speed to match your wheel speed, thus giving you maximum power when coming out of the corner. But won't you get the same results by downshifting & engine braking into a corner, keeping your right foot hovering over the gas pedal and accelerating asap? any insight/experiental knowledge is welcome. Thanks!
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02-16-2009, 09:04 PM | #2 |
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just so you know it's harder to heel toe on drive by wires, but the main advantage of heel toe is that you slowed down your car to entry of a corner while you rev up to match the downshift and keep your car at higher rpm to keep the torque and power. and higher rpm usually means more traction. so you basically used 0 engine breaking. because engine breaking you loose speed...
so basically you are coming into a turn, then you break to keep your car's nose down a little, at the same time you rev and downshift entering the turn, by then the time you enter you are at the proper gear and speed, usually 1-2 gears down. and midway into a turn all you have to do is finish the turn by fully gas...and what's the different from engine breaking and gas? you don't kill your clutch with heel toe, and it's faster. |
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02-16-2009, 09:14 PM | #3 |
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Thanks for the input! I think I'm starting to get it, I'm not sure why, but this just seems like a hard concept for me to wrap my mind around. I guess once i get out there and start playing around with it, it'll become more apparent.
also, not to sound like a complete novice, but what exactly is "drive by wire?" I presume it has something to do with electronically controlled gas/brake pedals, i.e., in newer cars like a new BMW, the gas and brake pedals are really just connected to electronic sensors which then tell the cars computer to accelerate or brake accordingly.... is that correct?
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02-16-2009, 10:08 PM | #4 |
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Presume you are entering a corner, using MAX braking, with a little turn into the corner.
Downshift, a gear lower, without rev'ing the engine. IF you are already at MAX braking, the instant you let out the clutch (with a low engine rpm), the rear will lose traction, and you swap ends. If you are NOT driving at the limit, the nose will dive a little, you will notice a speed decrease. AND you be watching the competition in the distance. Just my way of thinking. DJ
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02-16-2009, 10:27 PM | #5 | |
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Quote:
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02-17-2009, 08:49 AM | #6 |
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I'm a bit confused. How can braking and down shift with rev be done at the same time? I just don't have enough feet for that or is there an order to the technique? Also, is it possible to down shift at such high rpm's? would you have to double clutch to be able to get the car in a lower gear?
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02-17-2009, 08:52 AM | #7 |
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the trick is brake first and do the clutch rev and downshift together as 1 step. so said gear 5 to 4 do it once, and 4-3 do it again. that probably only take you less than a second
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02-17-2009, 09:29 AM | #8 |
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actually why don't you watch this clip
it's drift king driving sti, he heel toe a few time in the time attack, watch how he did it in lower speed turn and still keep the engine roaring |
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02-17-2009, 09:32 AM | #9 |
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I ask because last year I took advantage of a track day and had a great time. The only issue I had was down shifting from 3rd - 2nd at high rpm. I couldn't get the car into gear until the rpms went down a bit. Was the gear not engaging because I wasn't revving up while shifting?
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02-17-2009, 09:36 AM | #10 |
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i was going to suggest... just seach youtube. i had some trouble figuring it out as well until i watched some professional driver doing it. it definitely helps clear things up, and heel-toe is def the way to go when driving hard like track or autox, and i also use it in everday driving to just make it smoother...
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02-17-2009, 10:02 AM | #12 |
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I'll share what I've learned from my track days and the skip barber instructors at the 3-day racing school I attended.
The goal of heel-toe downshifting is to match RPMs of the engine to the driveshaft's current speed. This way, the downshift is smooth. The advantages are two-fold: you are ready to power out of corner in the gear you need AND you downshifted to that gear without upsetting the balance of the car. As someone mentioned before this is VERY important if you are driving at the limit. The sequence of events is typically: 1) Apply brake pedal with the left-half of your right foot. The ball area just before your toes works best. If the pedals in your car are set correctly, when braking hard the pedal should be about even with the gas pedal. 2) Push down clutch with your left foot. 3) Roll-over your right foot so that the right-half of your right foot "blips" the throttle. Depending on your situation and gear, the blip is soft or hard, but enough to bring the RPMs where they need to be. This is learned with practice. As you "blip" the throttle you must maintain the same pressure on the brake pedal as you had before. You don't want to stop braking or brake less when you blip. 4) Shift lever to lower gear 5) Let clutch out. A few tips: - Wear shoes with thin soles. That helps you feel the pedals better. Racing shoes are best, but running shoes work well. - It takes about 1000 heel-toe downshifts to master it. Don't get frustrated. Give it time - Practice everywhere: track, grocery trip, kid soccer practice, etc. - Watch out for hitting the gas pedal unintentionally at the same time you are braking. Try using your knee to roll your foot left and right as you work the pedals. That should help you avoid unintended pedal contact. - In some cars, its easier to blip the throttle with your heel. Some people also feel more comfortable doing it a different way. Feel free to experiment different foot positions see what works best for you. - You MUST MUST MUST downshift when you've slow down enough for the lower gear. If you do not wait, you will mechanically overrev the engine and ruin it. i.e, if you are on 4th gear at 7000 RPMs, you must wait until you brake enough for maybe... 4000 RPMs.. that way when you let the cluch out on 3rd gear, you will be at 7000 RPMs on 3rd. - You must change gear and let clutch out quickly after you blip. If you do not, the RPMs will come back down and your shift will not be smooth anymore. My $0.02. Disclaimer: The above instructions I provide as a guidance only. I am not responsible if you follow this post and something bad happens. You've been warned :P |
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02-17-2009, 10:17 AM | #14 |
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The reason you heel-toe downshift is to rev-match the engine with the new gear, for normal driving it makes the ride more comfortable, for fast driving/track driving, it keeps the car balanced. I think this answers the OP.
EDIT: sorry posted after Alows post, which is a good post! |
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02-17-2009, 10:56 AM | #16 |
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Most autocrossers do not practice heal-toe, since most of us don’t down shift after getting into second. There are a few cars that on a few courses gain an advantage of shifting up to third and back to second or going down to first again. The only ones that come to mind are the WRX STI, S2000 and maybe the RX8, it is only because of sort final gears or very peaky power bands.
The 128 and 135 should have enough gearing and broad enough power bands that once your into second you won’t need to shift again. Most of the time you’ll loose more time shifting than you’ll gain pulling out of a corner a little harder.
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02-17-2009, 11:00 AM | #17 |
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Thats a really good video you recommended. It answered a lot of questions I had about the whole heal-toe maneuver. Thanks!
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02-17-2009, 11:09 AM | #18 |
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it's not at hard as it might look. i picked it up real quickly. just realize that it's easier to do when you apply at least 50% brake, so you have that pedal travel. try it next time you make a right hand turn... go in a little hot, hit the brake, blip the throttle, shift, and bug out.
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02-17-2009, 11:12 AM | #19 |
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when i first learned it, i was practice the movement over and over again with the car off so it became muscle memory, the rest is really learn to listen to revs so you rev enough. because the last thing you want to do is going hot and screw it up.
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02-17-2009, 04:34 PM | #20 |
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Why do professional drivers heel-toe?
So they don't: 1) lock the driven wheels (the rears in our BMWs) when you let the clutch out, 2) burn up the clutch unnecessarily by slowing the car down with the clutch, 3) bang a valve (blow the motor, basically) by using too much engine braking, 4) all of the above. |
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02-17-2009, 04:57 PM | #21 | |
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2. going that fast i don't think they would gear brake for any reason, it's asking to drift...heel toe doesn't gear brake, you rev to match the gear. 3. again back to 2. engine brake, gear brake how ever you call it. 4. if not 1,2,3 then can't be 4. it's purely to keep power by the time we are getting out of the corner, and doing it in a fairly fast and efficiently. or else they don't have to heel toe, just brake and gas. |
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02-17-2009, 05:01 PM | #22 |
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oh let me add, incase someone comes in and said "it's to increase cornering angle!!!"
that's called left foot braking. heel toe doesn't increase your corning angle. it just allow you to keep power while slowing down in one step. it does the same thing if you just purely rev down shift and slow down while entering the corner. |
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