Tuning the TC

[kidrock]

will check that out once i get vdrift running again. want to work on this together? we can do it by each of us having to do so and so car. and then once were done we can put it on the svn. :?: :?:

[xTs]

Why not? But was just an early test. Talked to cotharyus, he wasnt sure about the values, cause i edited the bias. And i think my changes are too heavy, but see yourself.

[kidrock]

Will definitely check that out. I had done some work on the tc months ago but have since lost my work. i made it handle like a charm (brake wise) and would like to make other cars handle as good. heres a very general guide. start with one thing at a time (for example brake friction) and slowly get it to your liking.
May have vdrift running soon!
P.S. Once we commit something remember to add yourself to ohloh!

[cotharyus]

Remember something about the TC while you are thinking about / working on this - technically, it's a rally car. If you're tuning it on a tarmac track, you aren't going to have any idea what you have on dirt. Just FYI, I'm not convinced that most of the problems we're seeing with the car at this moment aren't suspension based - and I'm hesitant to mess with the suspension too much without a rally track.

[joevenzon]

Now I suppose the next question is this - does VDrift's ABS work individually on all four wheels, or if one wheel locks up does it back off on all four corners at the same time?

VDrift's ABS works individually on all four wheels. When the tire starts slipping more than is optimal, the brake pressure to the wheel is set to zero; when the tire is slipping less than is optimal, the brake pressure is reset to the driver commanded value. The ABS was written by me and wasn't originally part of vamos, so I know a lot about it.

I'm not sure why you guys are worried about the ABS -- are you just concerned because the wheels don't get to the point that they skid until you're moving slowly? Because that's desired behavior -- a perfect ABS system shouldn't ever lock up the wheels. At lower speeds this happens because the VDrift ABS controller can't modulate the brake pressure fast enough to avoid it (the wheels lock up too quickly).

The purpose of the ABS (and TCS, in the opposite direction) is to keep the tire applying its maximum force. When the wheel locks up it's applying very little force relative to its maximum, and it takes a while for the wheel to spin back up to the speed it needs to be at to apply maximum force, so having it lock up is bad. I can get into more detail about this if anyone's interested.

[xTs]

But you can see the ABS working, cause of the flashing ABS-sign. And it doesnt work until your under 20mph... so theres something wrong with the breaks. With my modifications you can see it working at every speed... (how it should be)

[cotharyus]

Joe - My concern with the ABS function was related to bias adjustments. The information you have given clearly shows that it's done correctly, and that setups should work as intended under almost any situation.

xTs - The brakes on most of the cars in the game were entirely too weak when I started working on the cars last year. I made it through a lot of them making changes, but I don't think I ever got as far as the TC, so your notion that the brakes are not strong enough is likely right on. I commited some changes last night that make it better, but I'm still not entirely happy - the brakes could be a little stronger, but the stronger they get, the more twitchy the car seems under braking. I'm wondering if this isn't due to the fact that it's AWD, which brings me to another question for Joe -

Joe - does the AWD on vdrift behave as though it has a center differential like a rally car, or true AWD, or are the front and rear wheels hard-linked like, for instance, a truck?

[kidrock]

We should have two cars. TCD (the Tc for dirt) and TC (the tc for tarmac). The reason is that Rally cars don't always race on dirt and as of now, we don't have any dirt! so we need to test on tarmac.
Cotharyus- Not sure but i think its center differential


P.S. Can somebody move this from bugs to cars and tracks and change the name to something like "Tuning the TC"?

[xTs]

Uhm, well, someday vdrift shall get a car edit menu. So i dont think there is really need for two versions of the TC. As we just have street tracks right now, we should use tarmac tires until we have an off-road track and can change the tires ingame.

kidrock: Would like to do this, but no rights

[kidrock]

Its a long time until the edit comes around so lets just leave the tc alone for now. we need a dirt track!
(at least change the name then?)

[cotharyus]

Changing the tires to tarmac from off road is easy.

[xTs]

Not in game... not without changing many things that have to be revoked, when the car edit menu (or maybe even a car profil menu) exists.

But currently i tend to give it tarmac tires.

[cotharyus]

Ok, more tarmac like tires put on the TC, some minor suspension changes, brake changes, etc. - Try it. Tell me what you think.

PS: Mosport: 1:27.400

Probably pretty accurate.

[joevenzon]

Jdoes the AWD on vdrift behave as though it has a center differential like a rally car, or true AWD, or are the front and rear wheels hard-linked like, for instance, a truck?

AWD isn't supported by vamos, so enabling it at the moment is just a dirty hack. I'm not sure what the real world analogy would be. I did a quick look through the code and it seems like the engine drives the rear wheels through a differential (the one specified in the car file), and whatever driving torque is applied to the left rear wheel is also applied to the left front wheel (and same for the right side). This must be why I had to halve the torque for AWD cars to prevent them from being super fast.

[xTs]

cotharyus: Well, you commited your records.txt so we all can see

How do you do this? TCS/ABS activated? Joystick? I dont get under 1:40, but with keyboard and no ABS/TCS.

And i think that the tires still have too much grip.