GY-Z

any one know when my tire's height changed, and threw off VDC.
does only the VDC won't work?anything else will happend?
and i belive that i when i turn it off from the buttom, it couldn't turn off my vdc completly rite?
how about the traction control?
does still works even my vdc is off?
thanks

joust75

iTrader: (1)

WTF does that mean????????? If you want help you need to type something we can understand.

If you are asking what i think you are asking here is my answer. When VDC is off TC is off as well!

There is currently no way to turn off VDC permanently.

GY-Z

sorry for the bad eng
basically i am asking that when i change my overall diameter of the tire, the vdc got throw off.
what will happen?

jckolnturn

iTrader: (1)

Oh that's so much better.

NismoKid

Are you saying that you want to get new wheels and want to know if the VDC won't work properly? If that's what you're saying, it depends on the rim and tire size.

joust75

iTrader: (1)

GY-Z

nope, i actually know what size of tire will throw off the vdc, just wondering what will happend if the VDC funtcion is diable.
will the TCS still running?
thanks

NismoKid

Sorry I can't be that much help, I drive a Base. I love not having a computer drive for me...

Z1 Performance

iTrader: (564)

doa search - asked and answered 100 times

D'oh

I disagree with this.

After numerous AutoX and track days, I strongly believe that the VDC does turn off all the way when you switch it off.

Of course, it will always turn back on when you re-start the car, and maybe this is what is meant above. In which case, I agree....

So, depending on your new tire sizes, VDC MAY be affected.

If it is affected, turning off VDC also turns off Traction Control; they are linked.

-D'oh!

joust75

iTrader: (1)

Permanent means permanent. The VDC does shut off completely when you turn it off this is a moot point. So you should not 'strongly believe' it you should no it.

Like I said, it cant be turned off permanently and I am sick of turning it off and even sicker of staring at that dumb yellow light!
I posted a thread on this a while back!

GY-Z

since the search function is down..i did go through every page.
and yet, have not found an answer..
perhaps anybody can help me?

pLacebo

Search is broken x 100

digerydingo

Like all the European traction systems when you turn off VDC it does shut off.... until you hit the brakes. As soon as you do it clicks back on 100% and stabalizes the car guaranteed. Mercedes, BMW, Volvo and Audi are all the same way. Try it in a parking lot. Shut off VDC, build up some descent speed and hit the brakes as hard as you can and steer hard one direction. The Z will still understeer badly. Even if you had a 90% understeer biased car with ABS it would still oversteer in that kind of situation. Once your off the brakes it should/would shut off. It's still debated whether is shuts off even when your not on the brakes, where you hear people suggest 20% to 5% engagement still.

Do'h: Try to think when your Autocrossing and I'll have you a bet the Z is a handfull with lift throttle oversteer and tail sliding through slalom but as soon as you touch the dreaded brake pedal the understeer rears it's ugly head. Like trail braking into the long sweepers where the car understeers until you lift enough brake that the momentum finaly overcomes the system and then trying to hold back on the gas cause your so frustrated with the understeer but don't want to lose more time switching into oversteer.

dwnshift's race team ended up ripping out all the electronics, with respect to engine management, to make sure the VDC was removed because even when they tested with VDC off and new balanced suspension they still had problems trail braking. Even Sport Compact Magazine had a problem when trying to execute a brake stand for a cover shot. As soon as they dumped the clutch everything was proceeding great and right when they breathed on the brake pedal to hold the car in place, pow, she stalled out, everytime. They solved it by pulling the fuse to the brake lights which is apparently how the system turns on and off. Once out they could do it no problem, however, we all don't have the luxury of traveling around with no rear brake lights.

DriftinZ

No brake stands???? I havent tried yet, still getting use to the car. But...no brake stands???

zuddenly

i have never thought about the understeer that way... i have to agree with D'oh that the car feels like the VDC is completely turned off at the autoX... i've tried it on and off and the Z behaves like two different animals... since my car is still stock, i have been blaming the understeer because of its original setup with tires and all... but even then, i can still get my tail to the side... my biggest question right now is when i do change tires... would getting 265 all around mess with the VDC? this may sound like such a newbie question and i apologize in advance, since i cant do a search now.

GY-Z

u should have 265/40/18 (front) and 265/40/18.(correct me if i am wrong).inorder to have the vdc running.

D'oh

I still disagree with this.

Almost any car can be made to understeer by heading into a corner too quickly and braking while turning (or just by turning alone). Once you start to plow, your front wheels are essentially skidding sideways and even light braking will cause the ABS to activate. You are correct in that some cars will go into oversteer, but at the same time others will not.

I am still convinced that what you are experiencing is simply the ABS due to the slipping front wheels. But, I'll keep that in mind if I notice anything fishy.

GY-Z, you are still talking about having the front and rear tires the same diameter. I have driven many a mile with 265/35-18 R compound tires with VDC active and have not had a problem yet, but others have had problems with setups closer to stock than mine. I think if you go with 265/40-18 you may have everthing work and you may not. If you are at all concerned, you should look for sizes closer to stock. The 265/40 is about half way between the front and back, so maybe you could go with a 245/40 in front and the 265/40 in back. Both sizes are only couple percent smaller than stock.

-D'oh!

failsafe

I'm with D'oh- after quite a few track days I have never felt the VDC engage when I've switched it off. My ABS will engage at the track as a result of late braking and starting the turn in while still on the brake. But this is a very different feeling than VDC.
If the VDC is "always enabled" (even when switched off) then how come it doesn't come on under heavy cornering? I've forgotten to turn off the VDC at the beginning of a session a few times and it's almost impossible to drive the car hard and fast through corners. It dramatically kills the power. So even if it was still running at 20% (when switched off) I think it would be pretty noticable.

archman350z

OK guys, I've gotta clear up some issues here:

First, the Z has been designed to understeer at the limit. You can thank sue-happy America and corporate lawyers for this. The Z uses a staggered tire size (i.e. the rear tires are wider than the front), which promotes understeer. Yeah, it may look cool, but it's a crappy handling setup. The rear sway bar is weak, this also promotes understeer.

I've heard the debates several times about VDC and if it is really ever off. I can attest to the fact that there is no interference from the system when the button is "OFF." I've spun the car many times (in controlled environments). This should not be possible if VDC is engaged. Technically speaking, it is impossible to have VDC engage at only 5% or something...either it will correct the yaw rate of the car, or it won't: 100% or 0%, take your pick. However, there does seem to be an error code that will be set if you spin the car hard enough with VDC off...Big Brother may be watching.

Trail-braking (a.k.a left-foot braking): the refusal of the Z to respond to trail braking is not the fault of VDC (if it is turned off): it's the fault of ABS. Nissan is among several manufacturers which offer a feature called "Electronically Distributed Braking." Basically, they are controlling the brake bias (front to rear) based on which tires have the most grip. Say that you put 100lbs of sand in the back of the Z...the system will apply more braking force to the rear tires because they have more grip. How does the system tell which tires have more grip? It looks at the wheel speeds. If it sees a particular wheel slowing down at a faster rate than the others, it will reduce braking force to that wheel since it will "think" that it is slipping. The art of Trail-braking involves getting the rear tires to slip (plus weight transfer to the steering tires) such that the car will become easier to rotate. Can you see how Electronically Distributed Braking and Trail-braking don't get along?

Knowledge is power.