Grass / Curb "Bug"= Extra Acceleration

  • Thread starter grog
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grog

grog

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I've noticed this with go karts in the past, by running in the grass it will cause some wheel spin which doesn't actually slow you down, it will actually gain a few MPH over karts on the pavement.

So this dynamic is now playing out in the GT academy. Check the replay of the fastest player on the test 1-2. He/ she's exploiting this "glitch" by running 2 tires over the curb and in the grass, which causes wheel spin which leads to extra Power / acceleration.

I tried this technique myself and definitely got more acceleration when doing this. Now I feel bad for doing so, since my fastest lap is now a "dirty" lap which should be dissallowed, too bad I can't void the lap myself.

Anyway I hope this gets fixed soon.

EDIT: whoever changed the title to imply this thread is about corner cutting was way off base so I changed it to reflect what the actual issue is.
 
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May be the comparison sounds a bit crazy but... don't you see Initial-D when Takumi puts the inner wheel in the ditch? This is the same principle?
 
I believe that the nissan leaf has an open differential, which means that by putting the inner tire on the grass, the outer tire is free to rotate at the acceleration demanded by the added radius of the cars width. Ordinarily (read as on pavement) with an open diff the outer tire can not use all of the torque. Sometimes one wheel drive is better than 2 wheel drive.

And jaycee that comparison also apply depending on the size of the curb.
 
If we are going by WRS rules here, you are allowed to put no more than 2 wheels off the track so it isn't actually dirty. I did this on the Eiger Nordwand Short test.
 
jaycee_xr3
May be the comparison sounds a bit crazy but... don't you see Initial-D when Takumi puts the inner wheel in the ditch? This is the same principle?
Click to expand...

Ha ha, While that technique allows you to carry more speed through a corner, this technique makes you actually speed up in the corner.

What i see happening is as the tires spin in the grass the motor will rev up slightly, and due to the cars low power is still gets great traction; And this all adds up to a few MPH more than a clean line yields.


Ross I'm not so concerned with lines as much as this "extra acceleration".
 
grog
Ha ha, While that technique allows you to carry more speed through a corner, this technique makes you actually speed up in the corner.

What i see happening is as the tires spin in the grass the motor will rev up slightly, and due to the cars low power is still gets great traction; And this all adds up to a few MPH more than a clean line yields.
Click to expand...

You can't blame the driver though for a bug in the programming?
 
grog
What i see happening is as the tires spin in the grass the motor will rev up slightly, and due to the cars low power is still gets great traction; And this all adds up to a few MPH more than a clean line yields.
Click to expand...

Thats what happens with an open diff :D The way you said it makes much more sense than how I did though :P
 
This bug actually existed in prologue too, where some cars (generally awd) could go faster down the fuji straight by having 2 wheels in the grass. Surprised they haven't done something about it, although it may not be an issue when we get to the higher hp cars. It also may be tough to address since the car should technically have better acceleration if doing this causes the engine to run closer to the hp peak for any amount of time.

A typical real life example of this situation would be how some initial wheel spin is helpful on many cars during a standing launch- it allows the engine to run closer to the hp peak for some amount of time that it may not normally have done that if you had no wheel spin. Like the situation in the game, the reduced traction is giving better acceleration compared to no wheel spin.
 
It happen on the nurburgring too I believe. If you dont set the grass to realisitic, you can go on it in the final straight and gain some more speed than staying on the tarmac. Specialy on the uphill.
 
SohnVonStig
I believe that the nissan leaf has an open differential, which means that by putting the inner tire on the grass, the outer tire is free to rotate at the acceleration demanded by the added radius of the cars width. Ordinarily (read as on pavement) with an open diff the outer tire can not use all of the torque. Sometimes one wheel drive is better than 2 wheel drive.

And jaycee that comparison also apply depending on the size of the curb.
Click to expand...

1 wheel drive is dangerous, and not better than 2 wheel drive in any race application I've ever experienced. A properly set up chassis will "twist up" (acumen) on cornering to allow weight to shift off the inside drive wheel, helps stop the under steer. This works on front & rear wheel drive cars.
 
grog
I tried this technique myself and definitely got more acceleration when doing this. Now I feel bad for doing so, since my fastest lap is now a "dirty" lap which should be dissallowed, too bad I can't void the lap myself.

Anyway I hope this gets fixed soon.
Click to expand...

I'm with you on this. Couldn't imagine how the 1st place was so much faster until I watched his ghost, followed him and got much faster than my previous.

I tried to do a faster clean lap but can't and now I'm stuck with what I too consider a dirty lap.

T.
 
jaycee_xr3
May be the comparison sounds a bit crazy but... don't you see Initial-D when Takumi puts the inner wheel in the ditch? This is the same principle?
Click to expand...

I remember that, this leads me to believe that this isn't a bug at all. If that same idea was incorporated into the show, its not something new at all. Any how, I used this trick as well but don't feel like it was dirty. I kept 2 tires on the pavement, that's good enough for me.
 
So because a character in a Manga do it, it's not a bug and it's normal to be able to do it ?
Right there's something I miss obviously here.
 
RX-7_FD3S
So because a character in a Manga do it, it's not a bug and it's normal to be able to do it ?
Right there's something I miss obviously here.
Click to expand...

No. I think the point is, 2 wheels off, is considered clean.. An A-pex is often clipped, as long 2 tires remain (on track) it's a "clean" line..

It's normal racing rules.. GT5 generally allows 2 wheels off without a penalty..

Hope that makes some sense. :)👍
 
I don't see how an open diff will allow you to go faster by putting one wheel on the grass. In karts, yes, solid axle, less rolling resistance from the slipping wheel etc.

Unless the Leaf doesn't really have an open differential, or PD put an LSD on 'er.

leaf_gearbox.gif


Looks unusual. :odd:
 
In reality a drive wheel off in a car with an open diff leads to all the torque going to that wheel, and the wheel with grip getting starved. That will slow you down in real life as you spin up the wheel off the track and reduce torque to the wheel with the grip.
 
^ What he said ^

I do not see anything wrong with racing and taking two wheels off the track, PROVIDED it is not in violation of the game rules, OR a bug is being exposed. I won't do it unless it's a mistake... and I don't care if I don't get good lap times because of it. Because it'll be clean, and that's the important part.
 
Thanks for the heads up on how the top guys are 'bending' the rules...I was wondering how I golded these events but still ended up 18,000th !
 
But if you don't know about the bug you might still drive like that and then it's not really dirty is it?
 
It has nothing to do with a differential, it is just physics. I really hope somebody worked hard to get the Takumi ditch run worked into the events haha, it's fantastic.

Doing this in real life would be quite bad for car's tires/wheels, and suspension mounts most likely, but it is perfectly possible.
 
Alot of members of this forum seem to say "As long as you keep 2 wheels on track you are ok" I partialy agree with this but if the centre line of the car is off track I view it as a corner cut.

But it all depends on where you consider the track edge is...

I took some pictures of the number 1 ghost times at what I consider their most controversial points.

Picture from Round 1 Event 2

2mez7dj.jpg


This photo is questionable if its a cut or not, the game allows this, according to the 2 wheels on track rule most people follow here this is 'acceptable' but for me if the only part of your car on the track is about 40mm of tyre tread and 99.5% of your car is in the grass I view this as a cut.


Picture from Round 1 Event 3

DSC01065.jpg


Now this one in my opinion is a undeniable corner cut. All 4 wheels are beyond the white line (which is usualy considerd the offical track edge) But the game allows this. His rear left tyre is beyond the white line and on the bricks, his front left tyre is well beyond the white line and in the grass.

But for any of the members on here who reguarly hold racing leagues with leaderboards etc, would you allow the participating members to drive like this lap after lap?

Or for any of the members who hold regular time trial competitions if the number 1 time displayed this kind of driving for every corner when possible would you allow it and consider it a valid time?

Now I know what I feel on this doesn't matter at the end of the day, it's up to PD to decide what's allowed and what isn't, and I dont feel the drivers who do this should be disqualifyed. PD allows it so they take advantage of it, fair play to them. But I certainly do not consider this to be "clean" driving.
 
I use the 2 wheels on track at all times rule, but the pictures above are plain examples of abussed track limits.
 
andrewhake
It has nothing to do with a differential, it is just physics. I really hope somebody worked hard to get the Takumi ditch run worked into the events haha, it's fantastic.

Doing this in real life would be quite bad for car's tires/wheels, and suspension mounts most likely, but it is perfectly possible.
Click to expand...

The drains in Initial D work in the same way as the "slot" does in slot car racing - they provide additional centripetal force over and above what the adhesion of the tyres can provide on their normal contact patches.
On top of that, it still doesn't explain why the car can accelerate faster on the grass, because the additional lateral force of a groove / rut will slow (linear) acceleration down. Besides, the car is hardly on the limit of grip at those speeds in a corner of that radius to even warrant the use of such a technique in the first place. To top it off, there is no such groove at Curva Grande.

You can do it on Cape Ring, though, if you get it right. Which is where the danger comes in; go too fast and / or don't balance the steering angle properly and the car will be vaulted out of the corner, just like the aforementioned slot-car.
 

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