Decreasing radius corners

[ZionsWrath]

I'll be honest and reply the obvious. No this ins't a track.

I practice on nights I'm off from work (around 1-4 am) on several highway ramps near me.

The areas I am using are sufficiently free of traffic so more than 90% of the time there are no other cars and I have yet to see a police car patrolling it.

Flame me if you want but I'm just trying to learn basic techniques. And from the replies it seems there is more debate about what the best driving line is than those worried about where this is occurring. I'm just trying to learn a bit more, not trying to cause a flame war or hurt anyone.

[7thgear]

haha, if it's a 1-lane off/on ramp then you have no "line"

just scrub the speed off naturally and call it a day

[Tgionet]

The proper way to take any interchange is as sideways as possible.

[7thgear]

Originally Posted by Tgionet

The proper way to take any interchange is as sideways as possible.

[ame="http://www.youtube.com/watch?v=8uW6iGxcNqQ"]Is this the worlds best drift? - YouTube[/ame]

[Porsche]

Originally Posted by ZionsWrath

Flame me if you want but I'm just trying to learn basic techniques. And from the replies it seems there is more debate about what the best driving line is than those worried about where this is occurring. I'm just trying to learn a bit more, not trying to cause a flame war or hurt anyone.

You're welcome.

What BARN were you raised in?

[ZionsWrath]

Originally Posted by Porsche

You're welcome.

What BARN were you raised in?

Somewhere in here, I can't find a closer pic.

[rice_classic]

My over long posts are based simply on the diagram and the lines given. While none are ideal, if I had to choose, I would choose blue everytime, without out a doubt and I'm confident I would win, by a lot.

Originally Posted by 7thgear

i'm not sure what it is that you're trying to argue... that the blue line is always better?

Yes, essentially and only in the context of this picture and with the assumption that the exit of the corner is not immediately leading into another corner.

Originally Posted by comic0guy

But if you have a turn coming up to the driver's left

Of course. And clearly I'm making a specific assumption as recommending a full "track out" on exit.

Originally Posted by serialk11r

Those radii don't even look close to roughly the same. The green car can definitely go through faster.

If you move the corner exit out, the green car can maintain speed as that will stretch the radius out a little.

In between the two orange dashes it's very close. Also, if you move the blue line over on entry you also widen it's radius not to mention moving the exit out. Then the real difference between the green and blue car at that point will be that the blue car will have a vastly superior entry with negligible difference on exit.

Originally Posted by Porsche

Ah, but will the Blue car and the Green car be traveling at the same VELOCITY when they reach the point where they would be rolling on the throttle.

The green car would be traveling at a greater rate of speed due to preceding difference in radius.

Originally Posted by Porsche

It would depend on what preceded and followed this turn. If this turn followed a long, high speed straight, the Blue car would make up a lot of precious time in the approach, able to maintain a much higher speed for a longer time, albeit down into the apex of a (artificially generated) much sharper corner.

Indeed!

Originally Posted by Porsche

It would be interesting to observe video of this in real time.

I have a video of a bumper to bumper race between myself and another equal car at a track with a similar turn that followed by another turn (so no long straight) and the difference is clear. PM if that is of interest to you.

Originally Posted by Porsche

The Blue car is clearly on the optimum passing line if he's trailing the Green car into the corner. He'll get to the purple throttle application point before the Green car and will "take away the line" from the Green car despite going slower at that point. The Green car may be going faster at that point, but will be effectively blocked from exploiting that advantage.

Indeed. So the blue car is going to arrive at the point of returning to throttle-exit much sooner so a gap will be created, a delta between the two cars. The exit speed difference between the two cars will be different (even though I argue by not much) so in order for the green car to close that gap, the straight following all this would need to be very long.

Originally Posted by Porsche

But, the issue at the moment is which of these lines will yield the best lap time independent of passing strategies.

Let's make the assumption that the lap times between the two are identical and that this corner is followed by a long straight (allowing the green line to make up the gap created at entry).

If both are the same lap time what would you do? I would still choose blue as I feel it's safer, simpler and would be much easier to be consistent with. But that's me.


This has to be one of the more rewarding threads on this board. I was really looking forward to coming home from the track today and reading the responses.

[Tgionet]

Originally Posted by rice_classic

This has to be one of the more rewarding threads on this board. I was really looking forward to coming home from the track today and reading the responses.

And it was a complete thread hijack too!

To answer the op's question, since I didn't see if anyone actually did, just practice more. If you have a racing wheel and pedals with a clutch that's a great way to get used to heel and toeing and there are some really good sims out there e.g. iRacing, RFactor that can be pretty punishing if you're not perfect.

[Porsche]

Originally Posted by rice_classic

The green car would be traveling at a greater rate of speed due to preceding difference in radius.

Yes.

Indeed. So the blue car is going to arrive at the point of returning to throttle-exit much sooner so a gap will be created, a delta between the two cars. The exit speed difference between the two cars will be different (even though I argue by not much) so in order for the green car to close that gap, the straight following all this would need to be very long.

This is just a theoretical corner, so it's hard to say, but I'm thinking the blue car might pick up a good 2-3 car lengths over the green car through the first portion of this corner. I wonder how much speed difference there would be as the green car begins to catch up at corner exit. In my mind this is a slow corner at the end, but the green car might have a 5+ mph advantage.

Maybe. It's imaginary, so who knows?

And if we imagine that a longish straight follows this … I wonder how long it would take the green car to make up the deficit? Would he? Hmm…

Let's make the assumption that the lap times between the two are identical and that this corner is followed by a long straight (allowing the green line to make up the gap created at entry).

If both are the same lap time what would you do? I would still choose blue as I feel it's safer, simpler and would be much easier to be consistent with. But that's me.

Heh. Now this is getting even more interesting, isn't it?

It's one thing to evaluate this in isolation, computing optimum speeds and time passing through this interesting corner only one time. But make it a race, and now other factors loom large.

Like you, Rice, my money is on the blue car.

Apart from my suspicion that this is simply going to be the quick way around the track, not just this turn in isolation, but the whole lap, the driver on that outside line has got his work cut out for him.

Under pressure, lap after lap, the green driver is going to find it more difficult to exploit the maximum from his tires and car through that corner. Not much margin for error in my imaginary corner, here. He would be far more likely to ease back a little for security (which would cost him dearly), and he'd be more likely (I'd guess) to make a mistake that would cost him even more.

Now, the blue driver can push the limits of his threshold braking and turn-in with greater security and with less likelihood of bobbling and make a right mess of it all. By COMPARISON, I'd say his job is far easier. By making fewer errors, he'd pull ahead just that much further as the laps mounted. His line allows pushing the limits with far more margin for error (lots of room on either side) and the car is flat and stable as he brakes down into the corner and changes down to his lowest gear shortly before doing his dirt-tracking, rallye turn around that sharp corner. It's not that it's easy, per se, it's just a lot less prone to time-robbing error than what the green driver faces, especially as he tries to change down while cornering hard.


Unless the green driver is a real pro, he's likely to become frustrated and flustered, yet again promoting the likelihood of mistakes. This would be especially so, if racing in close quarters.

Now, taking your scenario where they're turning equal lap times: Yes, but they're presumably "alone" out on the course when they qualified. With equal times, when it comes to the race this means they're likely to arrive at this imaginary turn of ours TOGETHER!

Uh oh.

Now things get much more interesting.

The green driver is likely to get distracted and flustered as the blue driver comes underneath him at corner entry (assuming the green is leading at this point). If green manages his line perfectly, and the subsequent straight is just long enough to make up the time lost on the approach, that'll put them neck-and-neck down that next straight, I reckon.


If blue is leading into this corner next lap, there's no room for green to get underneath him, not and have a hope of making the corner decently. Green will have to go around the outside, but that's not going to get a pass done on this corner, not with blue beating him down to the second segment.


And my NEXT question: Where's the FINISH LINE? Along this next straight? Down towards the end, maybe?

We've got a RACE! LOL!

My money's on Blue, but it could be exciting if green is an exceptional driver and is still there on the final lap.

By the way, Rice, I watched one of your race videos this past year and thoroughly enjoyed it. It was so exciting that I "sat beside" you for the whole race! And you took a great win! There are some beautiful segments to that circuit. I especially appreciated that downhill sweep through the woods with an interesting righhander at the bottom (iirc).

It even looks dangerous at some points. I like that. Modern motor racing circuits have been sanitized to the point that I no longer find most of them interesting

This has to be one of the more rewarding threads on this board. I was really looking forward to coming home from the track today and reading the responses.

This imaginary corner has proven to be quite entertaining, hasn't it?


I have enjoyed this.

Thanks.

[7thgear]

i dunno... i'd argue the opposite, the blue line requires perfect brake technique lap after lap, start braking 5 feet too late and you're gonna be overcooking the corner

at least the green line gives you more room and time to adjust things along the way

i dunno... as someone that does the greenline most of the time ***FOR Decreasing Radius Turns *** i find it easier to execute lap after lap... it's when i start experimenting with more aggressive attacks that require oversteer and greater rotation that i start to lose in terms of consistency..

[Wepeel]

Originally Posted by Porsche

Ah, but will the Blue car and the Green car be traveling at the same VELOCITY when they reach the point where they would be rolling on the throttle. I'm thinking the Green car will be traveling markedly faster and, thus, will have a "jump" on the Blue car out of the corner. The Blue car is just then exiting a much tighter and slower corner, despite now being on the same exit radius of the Green car.

Without knowing anything else about the corner and just taking the diagram at face value, that was my thought too. Especially with a car like the twins. The blue line looks more like an AWD turbocharged monster line. Seems the blue line car would make up some car lengths on entry but would be exiting lot slower - of course it depends on how long the exit straight is whether that would be faster or not.

[Frost]

Interesting points for both sides. Blue line is extremely aggressive and I hear what (s)he is saying about braking and turning.

I understand nothing here is to scale so hard to argue what is the most intensive points of braking and gassing and thus when you overload your tyres.

We really have to get a to scale map and car to do this... anyone want to meet up on a track?

I cannot say I know enough to argue convincingly one way or the other so until I've got an example, I won't add much more to this arguement that's useful.

[Porsche]

Originally Posted by Frost

Interesting points for both sides. Blue line is extremely aggressive and I hear what (s)he is saying about braking and turning.

I understand nothing here is to scale so hard to argue what is the most intensive points of braking and gassing and thus when you overload your tyres.

We really have to get a to scale map and car to do this... anyone want to meet up on a track?

Yes. That's why I asked the OP about whether his corner was on a race track and asked for the URL for said track. Precisely, so that we could take a closer look and possibly offer more useful suggestions.

Alas, the OP made unwarranted assumptions about my simple English question and obtusely interpreted my question as an attack.

Kids, these days.

I cannot say I know enough to argue convincingly one way or the other so until I've got an example, I won't add much more to this arguement that's useful.

And sometimes there's more than one way to skin a cat.

[Flat Black VW]

I just want to say that this thread has been an incredibly interesting read, I have done some auto-x and watched a lot of racing at local tracks (I plan to take my BRZ out next summer), so this has been a fun read.