trinydex

actually my point is to reveal all the science behind why it does and doesn't work. seems no one here likes learning about "what they already know."

dammitjim

Yes.

However the question you really need to be asking yourself is: if it's not smart enough to know where grip is, is it smart enough to know where grip isn't?

dammitjim

SlowTeg

That's fine.. then I'd say start a new thread and people can discuss it.

There's nothing wrong with trying to figure out the "why" for something, but I wonder how far we can really get without discussing the "how" as well, such as the VSA system, programming, etc. So far the "discussion" has largely boiled down to "but VSA doesn't react correctly in situation XYZ," but it's hard to know exactly why it reacts/how it's programmed for different situations. There's no question that VSA reacts very abruptly (and negatively if you're actually racing) if it kicks in, and perhaps people would prefer a system like on the EVO which doesn't "unsettle" the car, but I'm not sure there's any "fix" short of simply turning VSA off.

The VSA system was designed so J6P's wouldn't wreck the car moreso than a racecar, and has obvious limitations.

trinydex

this is obvious as you purposely strawman the points i make and divert it to something else that suits your argument, or just diverts to something else entirely. which is also why i'm done here.

dammitjim

I answered your last question with "yes"

SlowTeg

To clarify for trinydex, since he seems to be confused here.. An active diff is a form of "traction control" (like in the EVO). Yes it doesn't use the brakes like the s2k and is much less harsh, but it's merely another "form" of "traction control." If the computer detects more slip than the system is programmed for in the front in a certain situation, it can shift that torque to the rear. This IS traction control. You say toMAYto, I say toMAHto. Same thing. The distinguishing factor for "traction control"/VSA is basically having a computer controlled system. A closed diff != traction control/vsa.

trinydex

here was my original point, there is a conceivable situation where vsa can put the car over grip threshold, into a slide (because vsa can't ADD grip, it can only take away grip). the car will slide because in an understeer situation it will pulse the matrix of brakes that makes the car oversteer more. in an understeer situation it will pulse the matrix of brakes that promotes oversteer.

none of this brings you further INto the turn. it can only push you further OUT of the turn.

as such, in my experience vsa engages prematurely as to try to prevent such situations from happening, so as to promote a lower speed as to not go over ultimate grip threshold.

however i've also experienced the slide i speak of.

you suggested all this was impossible and you did so on the basis of saying that vsa is so smart it can somehow find grip when you've already maxed out the available grip. this is kind of odd to argue about simply because the situation i posed not only has happened in real life, but i already defined it as having possibly gone over 100% static coefficient of friction grip threshold.

(there's always at least kinetic coefficient friction working, but in a situation where you'd in the realm of kinetic coefficient of friction any traction system would be useless until the kinetic coefficient of friction has slowed things enough to the point where a static coefficient can be established at which point a traction or stability management system can actually do something meaningful.)

the bottom line is this, you can't create grip out of a no grip situation.

vsa absolutely has merits in that it can TRY to find a wheel that has grip to slow things down, but if that wheel that has grip is NOT in the matrix of brakes that promotes more stability... will it be used? and as such will it not promote instability until the system oscillates into another cycle and the stability encouraging matrix of brakes can be used? i'm sure it does... but that doesn't create grip from nowhere, a slide would be the result.

the very obvious benefit to all this is that it cycles much faster than a human can and it can target. however i already said that i've experienced the slide... i don't know what else there is to say.

SlowTeg

Trinydex,

Yes, that sounds correct. If you take a turn at 75mph that's rated at 15mph, there's very little VSA can do. Will it make the situation worse? Perhaps, but arguably you're F'ed regardless, so trying to argue that VSA will make things worse is like splitting hairs..

In the former situation though yes, it tries to prevent things while there's still grip available before the scenario is unrecoverable. Again, it's not perfect. It's just software.

To add, I wouldn't necessarily say that the VSA system "can't add more grip." If you're at WOT coming around a turn, reducing the throttle/applying the brake to the rear only/slightly can add grip. It can also promote understeer as weight is shifted to the rear via the rear brakes only. Of course, if the VSA system applies brakes over the friction threshold for the rear tires it'll be oversteer instead.

dammitjim

What is the point of your point?