racers line and ecoline minutia

[2000mc]

The racing line | Taking corners at speed | drivingfast.net
Racing apex is typically later in the corner to allow for more throttle on exit, where I think the hypermiling apex would be the geometric apex

[sqidd]

Originally Posted by Joris

Can you explain why you don't want to do that?

For practical purposes I'm going to refer to a single corner with higher straight away speeds (entry and exit) than corner speed to keep things simple.

A racing line assumes a few things. One, you are entering the corner a lot faster and two you are exiting the corner a lot faster while also trying to maximize your speed down the next straight by "driving" the exit. And three, the racing line is not about saving energy. It's actually all about using all the energy at your disposal. And lastly the racing line is a very flexible thing. It changes considerably from car type to car type. Car to motorcycle, etc. You can't look at a track map and simply draw the perfect racing line, no matter how much experience the driver has. You have to get out there and "feel it".

The goals of hypermiling (HM) are a lot different. The goal is to use the least amount of energy as possible. The easiest way to do this is to not slow down for the entry and not speed up for the exit. Of course in a lot of situations that is not possible, the corner will be too tight. So you have to figure out how you can get as close to that goal as possible. And a lot of that is going to come down to feel. You have to be able to feel when you're scrubbing speed (loosing energy) so you can retain as much momentum as possible.

The feel is very, very hard to explain. You can read 100 books on how to go around corners and I will still be able to teach you more about the subject in one day of hands on driving instruction. It's all about the feel.

You can absolutely learn about going around corners efficiently by reading about it. It is important to understand the vehicle dynamics, techniques, etc. But unless you take those lessons and go out and practice and feel them you will only have a very rudimentary understanding. Driving fast (or in this case efficiently) is a lot like sex. You can explain sex to a virgin for years and years, show them movies and even have doctors come in to explain the mechanics of what the body goes through. But until they actually have sex they simply won't understand.

I professionally road raced for 10yrs. Won championships, lots of races, set lap records, etc. I've worked as a driving and riding (motorcycle) instructor. I've also worked for Pirelli and Michelin as a tire tester and Ohlins, Penske and Matris as a suspension tester.

I've just started this hypermiling thing when I got my Focus. One of the first things I did was figure out how to go through corners as efficiently as possible. I assure you it is not the same as a racing line. You can use racing line and vehicle dynamics knowledge as a spring board to feeling out the "efficient line", they are quite a bit different though.

[sqidd]

Originally Posted by RedDevil

There is no simple rule of thumb to prescribe the ideal throttle, line and speed for hypermiling corners.

I disagree. There is a simple rule of thumb for hypermiling. It is to slow down as little as possible so you don't have to speed back up.

The trick is figuring out how to do that.

[sqidd]

Originally Posted by 2000mc

The racing line | Taking corners at speed | drivingfast.net
Racing apex is typically later in the corner to allow for more throttle on exit, where I think the hypermiling apex would be the geometric apex

That's backward, you early apex a corner so you can get on the gas sooner.

You are correct though that you are shooting for a constant radius when hypermiling (in most corners).

[RedDevil]

No, he's correct. It may sound counter intuitive but the apex is later in the corner if you want to hit the gas sooner.
The apex is where you hit the inner limits of the track. That is not the point where the radius is smallest, unless you do a neutral corner. If you get on the gas early, or late, the point of smallest radius moves one way and the apex moves the other way.

You've seen that link 2000mc provided? That should make it clear.

Originally Posted by that link:

It's very common for drivers to apex too early due to nerves about the approaching corner and eagerness to take the turn. The racing line apex which is often out of view at the point of turn in, or further round the corner than you expect

[sqidd]

Originally Posted by RedDevil

No, he's correct. It may sound counter intuitive but the apex is later in the corner if you want to hit the gas sooner.
The apex is where you hit the inner limits of the track. That is not the point where the radius is smallest, unless you do a neutral corner. If you get on the gas early, or late, the point of smallest radius moves one way and the apex moves the other way.

I think the problem here is how some people define early and late apex, it's common.

A lot of people (and what is happening here) describe early "turn in" as a early apex. They are not the same thing.

The apex of your line is not the same as the apex of the corner. If you early apex a corner you get the turning done (or most/more of it) before the apex of the corner. This straightens out the exit and allows you to get on the gas sooner. This is how you drive/ride something that has more power than lateral grip. Motorcycles (especially fast ones) and NASCARs for example.

To early apex a corner you delay your turn in (effectively "blowing it"). Then slow down a little more to sacrifice apex speed which allows you to turn in/more faster. Get your turning done real quick, straighten it out and dive hard through the corner onto the next straight bit.

In NASCAR is it called "backing the corner up". They apex early (before the actual apex of the corner) and then drive it down the next straight. backing the corner up means they are getting the turning done earlier. You will see them do this a lot at the shorter tracks.

If you are early apexing a corner correctly you will be hard on the gas as you pass over/by the physical apex of the track.

A lot of it is symantics. I can assure you in the racing community most people describe an early apex as turning before you get to the actual corner apex.

[sqidd]

This for example is not how most racers talk to each other. Note in the diagram that they are calling it a late apex because they are referencing the track/corner. When racers talk they reference the line, which is the only thing that matters.

It's a widely mis-used term(s). But just because "everyone does it" doesn't make it right. What matters is what is actually happening. And what is happening is your line is apexing early (before the apex of the corner).

[2000mc]

I think it's easy to have the terminology twisted around, which is why I also put up the link. Looking at the shape of the path the car follows, it makes more sense to call the apex the point where you are turning the sharpest. For whatever reason I always have, and what seems to be at least a lot of people call the apex where ever you hit the inner most point of the track in a turn, but looking at the path of the vehicle, it doesn't make sense

[RedDevil]

Wikipedia uses clipping point as a synonym for apex.
So the apex is the point where the racing line hits (clips) the inner boundary of the track. It has nothing to do with the point where the turning radius is smallest, whether such a point were easy to determine or not.

[sqidd]

Originally Posted by RedDevil

Wikipedia uses clipping point as a synonym for apex.
So the apex is the point where the racing line hits (clips) the inner boundary of the track. It has nothing to do with the point where the turning radius is smallest, whether such a point were easy to determine or not.

You can call it whatever you like. You can be the "rightest" person to ever post on this board. I'm OK with being the fastest.