Traction Control
Hmm, wouldn't ABLS be a hinderance, then, for people that have aftermarket diffs?
I think we're on the same page as far as what's off with the button. Technically, though, if ABLS is one of the many VDC finctions and remains on when in "VDC off" condition, then one could argue that VDC is not completely off. You're right, at this point, it's a mater of semantics.
I think we're on the same page as far as what's off with the button. Technically, though, if ABLS is one of the many VDC finctions and remains on when in "VDC off" condition, then one could argue that VDC is not completely off. You're right, at this point, it's a mater of semantics.
Hindrance? Possibly. I would hope that if I spent $1,000+ on an aftermarket LSD, it would react well enough that the ABLS wouldn't sense the need to activate.
In any case, I WANT my ABLS to function when I'm on the track. Who doesn't want an intelligent limited slip to help them put the power down? Shutting it down is certainly not a performance upgrade!
In any case, I WANT my ABLS to function when I'm on the track. Who doesn't want an intelligent limited slip to help them put the power down? Shutting it down is certainly not a performance upgrade!
vdc
Originally Posted by Zmazing03
VDC won't bother you unless you are going ***** out around a corner. You turn off that TCS, and its not hard at all to screw up. VDC isn't going to save you.
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Joined: Aug 2002
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From: SF, freezing my @ss off
Originally Posted by Kolia
We're getting into sementics here. But if we look at the definition of what each systems are designed to do, we'll find that the VDC is there to change the car's direction relative to the steering input. That part of the electronic package is completely turned OFF when we hit the VDC button.
I think people are confusing VDC OFF with an imaginary "All electronic OFF" button and thus have the wrong expectations.
For the ABLS + VLSD thing, I'm not a drivetrain designer but I know that visous lock LSD can't be 100% lock ever. The lock ratio is a function of the temperature of the viscous fluid. The hotter, the ticker it gets. It get warmed up by a speed differential between the left and right wheel. So as soon as they both spin at the same speed, lock is released and one wheels can go free spinning again.
The ABLS will be able to assist the VLSD (which would have a hard time locking at low speed, might be the 20mph you've found) to make sure the wheel speed is kept equal. I suspect the ABLS will also be aware of the car's attitude so it doesn't try to lock the diff in a sharp corner. So it's still getting data from the yaw and steering sensor as long as it's active.
Why add the ABLS to the VLSD in the first place ? Pricing I guess. The diff is a cheap one to get and all the electronic hardware for the ABLS is present with the VDC package. So it's "free".
I think people are confusing VDC OFF with an imaginary "All electronic OFF" button and thus have the wrong expectations.
For the ABLS + VLSD thing, I'm not a drivetrain designer but I know that visous lock LSD can't be 100% lock ever. The lock ratio is a function of the temperature of the viscous fluid. The hotter, the ticker it gets. It get warmed up by a speed differential between the left and right wheel. So as soon as they both spin at the same speed, lock is released and one wheels can go free spinning again.
The ABLS will be able to assist the VLSD (which would have a hard time locking at low speed, might be the 20mph you've found) to make sure the wheel speed is kept equal. I suspect the ABLS will also be aware of the car's attitude so it doesn't try to lock the diff in a sharp corner. So it's still getting data from the yaw and steering sensor as long as it's active.
Why add the ABLS to the VLSD in the first place ? Pricing I guess. The diff is a cheap one to get and all the electronic hardware for the ABLS is present with the VDC package. So it's "free".
Last edited by spf4000; Mar 4, 2007 at 09:11 AM.
Originally Posted by yellowlady
i have had my car for about two weeks, and i have been going crazy driving hard, but my front tire feels like the abs is working in fast corners. it freaks me out and i lift off the gas. so what is at work here? vdc senses slip iin the front tire? the car has hankooks in the front and generals in the back. i have read these are poor choices. do i just keep vdc off?
Chris
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Joined: Dec 2006
Posts: 7,337
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From: Edina, Minnesota
Originally Posted by yellowlady
i have had my car for about two weeks, and i have been going crazy driving hard, but my front tire feels like the abs is working in fast corners. it freaks me out and i lift off the gas. so what is at work here? vdc senses slip iin the front tire? the car has hankooks in the front and generals in the back. i have read these are poor choices. do i just keep vdc off?
Here is a posting on this Forum where a Moderator explains this quite well.
https://my350z.com/forum/wheels-and-tires/203755-will-these-tires-work-with-my-vdc-enabled-car-read-here.html
It’s a great read for anyone with a VDC-equipped Z considering a new tire purchase.
--Spike
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From: SF, freezing my @ss off
Originally Posted by Spike100
I think Chris has answered your question. Your tire circumference front-to-rear percent-difference is outside the tolerance VDC allows. When you hit a corner, VDC “thinks” you’re starting to skid, and it activates.
Here is a posting on this Forum where a Moderator explains this quite well.
https://my350z.com/forum/showthread.php?t=203755
It’s a great read for anyone with a VDC-equipped Z considering a new tire purchase.
--Spike
Here is a posting on this Forum where a Moderator explains this quite well.
https://my350z.com/forum/showthread.php?t=203755
It’s a great read for anyone with a VDC-equipped Z considering a new tire purchase.
--Spike
My suggestion would be to make sure the circumference is within spec, and if it is, match the tires front and rear.
My other suggestion...don't ever lift in a corner.
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Joined: Dec 2006
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From: Edina, Minnesota
^^^ Chris mentions this "You may be driving at the limits of your tires...".
Is it unusual for someone to put different types of tires front to rear? I've never even thought about doing that.
--Spike
Is it unusual for someone to put different types of tires front to rear? I've never even thought about doing that.
--Spike
thanks
i think it is the frnt tires. my sizes are as follows. 245 35zr19 up front, and 275 30 r 19 in the rear. i did not put these tires on the car or the 19" wheels, as i just got the car. to clarify my symptoms- going into a corner hard and one of the front tires feels like abs is being applied even if i am on the gas.
thanks,
chris
thanks,
chris
tire size
i just used the tire calculator and my rears are an inch smaller in diameter, than the stock tires. is this my problem? why would the issue arrise with one of the front tires?
thanks,
chris
thanks,
chris
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Joined: Dec 2006
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From: Edina, Minnesota
^^ one inch less in diameter on the back tires won't cause a problem as long as the front tires are within a similar range of difference from stock.
How close to stock diameter are your front tires? --Spike
How close to stock diameter are your front tires? --Spike
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Joined: Dec 2006
Posts: 7,337
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From: Edina, Minnesota
Looks as though you are over the 3% tolerance limit for VDC
Stock front tires: 225/45-18 Diameter: 25.97”
Your front tires: 245 35zr19 Diameter: 25.75”
Diameter Difference is 0.85%
Stock rear tires: 245/45-18 Diameter: 25.49”
Your rear tires: 275 30 r 19 Diameter: 26.68”
Diameter Difference is 4.47%
I think you may need to invest in new tires.
--Spike
__________________
EDIT: Notice that your front tires are smaller than stock by 0.85%.
And your rear tires are larger than stock by 4.47%
The effective difference is 5.32%. That’s too much for VDC to handle.
_____________________________________________________
SECOND EDIT (made 3/5/2007 at 7:35 pm): I managed to reverse the overall Diameter values for the rear tires. The aftermarket tires have a smaller (not larger) overall diameter than the stock tires. yellowlady caught my error and pointed this out to me.
Stock front tires: 225/45-18 Diameter: 25.97”
Your front tires: 245 35zr19 Diameter: 25.75”
Diameter Difference is 0.85%
Stock rear tires: 245/45-18 Diameter: 25.49”
Your rear tires: 275 30 r 19 Diameter: 26.68”
Diameter Difference is 4.47%
I think you may need to invest in new tires.
--Spike
__________________
EDIT: Notice that your front tires are smaller than stock by 0.85%.
And your rear tires are larger than stock by 4.47%
The effective difference is 5.32%. That’s too much for VDC to handle.
_____________________________________________________
SECOND EDIT (made 3/5/2007 at 7:35 pm): I managed to reverse the overall Diameter values for the rear tires. The aftermarket tires have a smaller (not larger) overall diameter than the stock tires. yellowlady caught my error and pointed this out to me.
Last edited by Spike100; Mar 5, 2007 at 04:36 PM.
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From: SF, freezing my @ss off
Could it possibly be that your front tire is rubbing against the fender liner? Under hard cornering, your outside front will be under compression so it may be rubbing in places if your wheels' offsets are not ideal. Just a thought.
You know in all I have read, it really has nothing to do with the percentage difference from stock, it has to do with percentage of difference between the front and the back.
I am not sure where Spike100 got his numbers but by my calculations the 245/35 has a 25.75" diameter while the 275/30 has a 25.50" diameter.
So you are shorter in diameter at the back and this has been found time and time again to cause VDC to go into "SLIP" before the tires have actually let go. You can switch the fronts to 245/30s or the backs to 275/35 (recommended) and your troubles will go away.
Chris
I am not sure where Spike100 got his numbers but by my calculations the 245/35 has a 25.75" diameter while the 275/30 has a 25.50" diameter.
So you are shorter in diameter at the back and this has been found time and time again to cause VDC to go into "SLIP" before the tires have actually let go. You can switch the fronts to 245/30s or the backs to 275/35 (recommended) and your troubles will go away.
Chris
again thanks
first of all the generals and hankooks are not great choices anyway- right.
the front tire is virtually the same diameter as stock, but the rear is over an ich smaller in diameter. this is the culprit. i know i could do a search but we might as well just keep it flowing here. current front is hankook 245/35/19-diameter seems to be perfect, however the tire seems to be stretched on the rim. the rim lip protrudes past the tire. tire sidewalls usually sit beyond the wheel to protect it. do i need to adjust my front tire size? current rear isis general 275/30/19. this tire is much smaller in dia. than stock. please recommend replacement sizes and brands. people here seem to like the bfg or f-1 goodyears.
thanks,
chris
the front tire is virtually the same diameter as stock, but the rear is over an ich smaller in diameter. this is the culprit. i know i could do a search but we might as well just keep it flowing here. current front is hankook 245/35/19-diameter seems to be perfect, however the tire seems to be stretched on the rim. the rim lip protrudes past the tire. tire sidewalls usually sit beyond the wheel to protect it. do i need to adjust my front tire size? current rear isis general 275/30/19. this tire is much smaller in dia. than stock. please recommend replacement sizes and brands. people here seem to like the bfg or f-1 goodyears.
thanks,
chris
bum tires
Originally Posted by Spike100
Looks as though you are over the 3% tolerance limit for VDC
Stock front tires: 225/45-18 Diameter: 25.97”
Your front tires: 245 35zr19 Diameter: 25.75”
Diameter Difference is 0.85%
Stock rear tires: 245/45-18 Diameter: 25.49”
Your rear tires: 275 30 r 19 Diameter: 26.68”
Diameter Difference is 4.47%
I think you may need to invest in new tires.
--Spike
__________________
EDIT: Notice that your front tires are smaller than stock by 0.85%.
And your rear tires are larger than stock by 4.47%
The effective difference is 5.32%. That’s too much for VDC to handle.
Stock front tires: 225/45-18 Diameter: 25.97”
Your front tires: 245 35zr19 Diameter: 25.75”
Diameter Difference is 0.85%
Stock rear tires: 245/45-18 Diameter: 25.49”
Your rear tires: 275 30 r 19 Diameter: 26.68”
Diameter Difference is 4.47%
I think you may need to invest in new tires.
--Spike
__________________
EDIT: Notice that your front tires are smaller than stock by 0.85%.
And your rear tires are larger than stock by 4.47%
The effective difference is 5.32%. That’s too much for VDC to handle.
i think this is correct, and i thank you, however i have different figures than you using the tire calculator. my rears appear to be smaller not larger than the stock tires. 275/30/19 is 1.2 inches smaller than the stock 245/45/18.
check it out and let me know
thanks,
chris
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Joined: Dec 2006
Posts: 7,337
Likes: 204
From: Edina, Minnesota
Chris… Your calculations are correct, and mine are wrong. 
I managed to reverse the overall diameters of the rear tires. 
Here is a new comparison chart (and I hope I got it right this time).
Stock front tires: 225/45-18 Overall Diameter: 25.97”
Your front tires: 245/35-19 Overall Diameter: 25.75”
Diameter Difference is 0.85%
Stock rear tires: 245/45-18 Overall Diameter: 26.68” *
Your rear tires: 275/30-19 Overall Diameter: 25.49” *
Diameter Difference is 4.47%
* These are the values I reversed.
So the calculation is not additive (as I wrongly stated in the previous post), it is subtractive since both front and rear are smaller than stock. However, the subtractive difference is: 4.47 - 0.85 = 3.62% difference. That is still over the 3% tolerance level for VDC to operate correctly. So it does appear as though you need to replace at least the front or rear tires to get inside the tolerance range for VDC.
Sorry for the confusion.
--Spike
BTW: I really like VDC. I do turn it off occasionally when the roads are dry and I want to drive a little faster. Even with the correctly sized tires, VDC will activate when you drive aggressively (on dry roads, of course) if you do a little bit of drifting while hard-cornering.
I managed to reverse the overall diameters of the rear tires. Here is a new comparison chart (and I hope I got it right this time).
Stock front tires: 225/45-18 Overall Diameter: 25.97”
Your front tires: 245/35-19 Overall Diameter: 25.75”
Diameter Difference is 0.85%
Stock rear tires: 245/45-18 Overall Diameter: 26.68” *
Your rear tires: 275/30-19 Overall Diameter: 25.49” *
Diameter Difference is 4.47%
* These are the values I reversed.
So the calculation is not additive (as I wrongly stated in the previous post), it is subtractive since both front and rear are smaller than stock. However, the subtractive difference is: 4.47 - 0.85 = 3.62% difference. That is still over the 3% tolerance level for VDC to operate correctly. So it does appear as though you need to replace at least the front or rear tires to get inside the tolerance range for VDC.
Sorry for the confusion.
--Spike
BTW: I really like VDC. I do turn it off occasionally when the roads are dry and I want to drive a little faster. Even with the correctly sized tires, VDC will activate when you drive aggressively (on dry roads, of course) if you do a little bit of drifting while hard-cornering.
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