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| Initial D World - Discussion Board / Forums > Technical Discussion > Initial D technical question. |
| Posted by: Sanders Apr 11 2017, 12:15 PM |
| Hello! Rewatching Initial D I notice one moment that needs some explanation. https://youtu.be/ltJkPMnh6J0?t=16m26s --- watching this moment you can see Takumi making heel&toe and after that we can see tachometer. The question is - why did the arrow of the tachometer firstly get down to 6 rpm and then go back to the 7 as if Takumi switched from 3rd gear to 4th, for example. Heel-and-toe should equalized pinion rotation and the arrow shouldn't "jumped down", am I wrong? Maybe after heel&toe Takumi continued to brake for some time and that is why the arrow went down for a little. By the way, is it okay, that he have 8000rpm on the third gear? Thank you! |
| Posted by: Nomake Wan Apr 11 2017, 01:12 PM |
| 1. Animation error. 2. It doesn't matter what gear you're in. As long as you aren't exceeding the mechanical limits of the engine you're fine. The stock motor has a rev limiter so it's fine. If it turns out that the rev limiter is lower than 8000, yet it shows higher than possible, then again...animation error. [ Post made via Mobile Device ] |
| Posted by: RedsunsF1 Apr 11 2017, 09:30 PM |
| It most definitely is okay to be up to 8000rpms. Just like B16b motor in a honda you see 12k RPMs. Like you said is correct. When i'm at the track i Heel toe all the time but sometimes continue to apply aggressive brake pressure and the rpms will drop instead of matching how they're suppose too but its kinda rare. |
| Posted by: Nomake Wan Apr 11 2017, 11:29 PM | ||
B16B stock redline is 9k. This is First Stage we're talking about here--the engine in the 86 is a tired old 4A-GE. |
| Posted by: Sanders Apr 12 2017, 03:20 AM | ||
I meant, is it okay that it were 8000rpm on the 3rd gear after downshifting, not during the acceleration. As far as I know the 3rd gear corresponds to about 4000 rpm, isn't it ? So this is the value on which tachometer arrow should be after heel&toe. |
| Posted by: Nomake Wan Apr 12 2017, 06:54 AM |
| I think you have a fundamental misunderstanding about how automotive drivetrains work. [ Post made via Mobile Device ] |
| Posted by: Spaz Apr 12 2017, 03:23 PM | ||
You're thinking about this backwards. Heel/toe is for downshifting, not upshifting, so when you do it you'll end up at higher RPMs in a lower gear, not the other way around. Depending on when you shift, you can pretty much be at any RPM in any gear. |
| Posted by: xiao Apr 13 2017, 08:36 AM |
| Also of note: some people (Takumi) have very small feet and need to actually do the heel & toe motion literally. But heel & toe is a very common motorsports technique, where most people myself included just use the side of the right foot to give the gas a little push & raise the revs thru the corner. Your feet are probably large enough to just hit-it with the side of your foot & avoid unnecessary jazz-hands on the pedals nobody can even see. Think of it this way Sanders, it's something you do out of necessity cause there's no other way to keep the engine rev'ed up on a curve. Cause if you don't break/down_shift you'll understeer into tree in the corner. I've found myself doing it even unnecessarily at low speeds on the road when I'm driving an MT.  |
| Posted by: Nomake Wan Apr 13 2017, 09:14 AM | ||
Most normal drivers with a manual transmission wouldn't be going fast enough for it to matter, and even if they were they would just abuse the synchros in order to get into the gear they want. And on top of that, nowadays a normal driver doesn't know how to drive a manual anyway. It's not that there's 'no other way' to 'keep the engine revs up', it's that it's the fastest way to downshift accurately without upsetting the drivetrain's balance unnecessarily while maintaining control over the brakes at the same time. |
| Posted by: xiao Apr 13 2017, 10:21 AM | ||
That reminds me of when I went to go test drive that silver FR-S last year & the guy was constantly encouraging me to take the Automatic. Dude was like, it's just a little bit more but it's just like a Manual! Look it's got paddles like Formula 1!  |
| Posted by: JKaiba Apr 13 2017, 10:35 AM | ||
N1 is absolutely correct. Xiao. I understand your want to interject what knowledge you believe to have on this subject but this seconded opinion is for the sake of not confusing Sanders and because you have demonstrated that you don't fully understand the technique in question, I ask that you defer this subject to more experienced drivers so that you may learn. While it's easy to rev match downshift while braking in a modern car travelling at normal speeds, you won't really understand the benefits of this sort of thing until you really get on the track and feel what it's like when you are forced to balance the car at its limit through a corner and you are only able to use one pedal at a time vs heeltoeing. You limit excessive over or understeer caused by the drivetrain suddenly coming on or off load if you had to take your foot completely off the gas then on again if you need to use brakes in the corner. Your weight transition becomes more precise. |
| Posted by: xiao Apr 13 2017, 10:40 AM |
Ohh ~  I thought the only reason to heel & toe was to keep the revs up thru a curve, so you can exit the corner fast after the break & downshift. But I totally agree with you & Nomake, just didn't know there was additional reason for heel & toe'ing!  I'll recede now. :x |
| Posted by: JKaiba Apr 13 2017, 10:49 AM |
| If you brake hard and immediately downshift before a curb and just peg it through the corner you can certainly keep your revs up that way too. Heel Toe is not always the answer for approaching all corners. |
| Posted by: xiao Apr 13 2017, 11:19 AM |
Edit: I think we're mixing each other up with semantics.  Here's a really interesting article I found on an F1 blog. I'd like to know Spaz's personal experience racing the Evo on the track/auto-x when people make the argument: ・ Heel & Toe vs Left Foot Breaking (click on the excerpt) ↓ http://formula1blog.com/editorial/paul-charsley-2/the-drivers-seat-right-foot-vs-left-foot-braking |
| Posted by: RedsunsF1 Apr 13 2017, 11:48 AM | ||||
Especially if you forget and keep holding the clutch down 
Yeah that is correct for the stock redline but that's not what i was saying. |
| Posted by: xiao Apr 13 2017, 11:59 AM | ||
Why isn't the car moving...!! |
| Posted by: Sensation! Apr 13 2017, 12:12 PM | ||||
I'm no track driver, but as far as I'm aware, how much torque you're making out of a corner doesn't really matter in the big picture because I don't think there's a general answer for this. The proper answer is that it varies from corner to corner. There's an underlying concept that I think you might not understand, and its actually a core to J's post; deceleration can also create notable torque. How much torque made depends on how fast you were going and what gear you were in. This torque is enough to affect how your car reacts dynamically during entry to mid-corner, and in addition, much of it is also determined by the characteristics of the differential(s). This is part of why heel-toe is not the answer for every corner. In the most general way to explain it so you can picture it (it depends once again depends on speed, corner, and car), this deceleration torque may cause understeer. EDIT of your EDIT:
This is the tech discussion forum. Nobody knows the answer to everything. You're here to learn something or you're here to contribute. |
| Posted by: Nomake Wan Apr 13 2017, 12:16 PM | ||
I know. And I'm saying you don't understand the context of this question, which was in reference to a stock 4A-GE engine. This is First Stage, not late Second or later. So using a custom-built rev-unlimited race engine as an example as to why it's totally okay for a stock 4A-GE to rev that high is bogus. |
| Posted by: xiao Apr 13 2017, 12:27 PM | ||
Quoted for truth. Yeah for me it's either speed or just for fun, every corner's different like you said. --- --- --- I rarely drive a manual & when I do ... I tell whoever the poor soul is I won't drive their car with them inside, otherwise they won't ever let me drive it again. It's not that I drive crazy ... or well ~ it's that I drive like a blindfolded man doing somersaults with the biggest smile on his face. |
| Posted by: Meteor Apr 13 2017, 12:47 PM | ||
Techniques like heel & toe are for affecting how the car behaves on entry. They don't do anything like change how much torque you get on corner exit, and trying to change that with driving technique is pointless. When you're taking a corner right, you'll be at the edge of the tires' grip all the way through and speeding up as you reach the exit, and your torque output will naturally fall as the RPMs go up because that's just how engines work - the engine just can't breathe fast enough at high revs to keep putting out all that torque. This torque falloff towards the end of a gear can even be beneficial, as it essentially acts like a form of traction control and improves stability while accelerating hard out of a corner. Professional race teams even adjust the car's powerband and gear ratios to make use of this. So tl;dr, stuff done on corner entry won't give torque boosts on corner exit, torque naturally goes down as you get close to the redline, and having lots of torque is only important when you've fully left the corner. To be really fast after the corner, all you have to think about is your corner exit speed. Also, deceleration torque can create either oversteer or understeer. It depends on how much of that torque is going to the inside wheel/s vs the outside wheel/s. But at this point we'll probably need to make a new thread to properly discuss this. |
| Posted by: RedsunsF1 Apr 13 2017, 01:07 PM | ||||
Wouldn't be a bad idea, i really enjoy these type of conversations and topics and hear everyone's input.
You're right my bad. |
| Posted by: xiao Apr 13 2017, 02:32 PM | ||
Meteor my friend you should work for McLaren's ⇒ R&D team ~   |
| Posted by: Nomake Wan Apr 13 2017, 02:43 PM |
| Proper modern cars don't need a technique like heel & toe anymore because the computers and multiple clutches will rev-match all the gear changes much more efficiently than you ever could. Merely knowing why the technique exists is hardly a valid qualification for being R&D for a major manufacturer. |
| Posted by: RedsunsF1 Apr 13 2017, 02:52 PM | ||
Oh man so true. Yesterday i instructed my friends 2015 Z06 and when i downshifted to get ready to turn it freaking rev matched for me like perfectly every single time. It's nice because that is just one less thing to worry about on track and be fore focused on track for beginners learning like himself but i still told him it wouldn't be bad to learn heel toe so he can get experience with other cars on track. |
| Posted by: Spaz Apr 13 2017, 06:03 PM |
| Meteor is dead on about getting the car to stay balanced and behaved, but there's an elephant in the room (well, maybe not) that I'll address. Heel toe can actually extend your braking zone, and the reason is the process itself. As you pivot your heel down to blip the throttle, your toe will naturally lift slightly off the brake as part of the same motion. You yourself won't notice it, but if you're lucky enough to have a car with a full telemetry suite, you'll be able to see it clear as day in the data that the braking pressure decreases in correspondence with the throttle blip. This won't be all that notable under light to mid braking, but under heavy braking where every inch of tarmac you spend at the threshold counts, it matters. I've begun to limit myself to a single throttle blip under heavy braking, toward the end as I begin my trail braking, even if I'm changing multiple gears. If I'm in 5th and need to be in 3rd for the corner, I'll clutch in late in the braking zone and go straight for 3rd with one blip, allowing me to stay on the braking threshold as long as possible. |
