rain handling
#31
07-12-2005, 05:43 PM
We had a few good storms here recently so I got a chance to hit some semi flooded roads in the G. I can say that the car did better than my Maxima, didn't pull into the water (curb) stayed very nicely planted on the road, and at no time did I feel uncomfortable. I actually like the VDC (never had it before) coming from some old American muscle cars that control terribly in bad weather. I did get on the throttle a bit coming off a turn just to see how it would react (it was safe) and the back did start to slide out a bit. A little ease off the gas (very little) brought it right back in line and off I was, probably didn't need to ease off, just habit.
In my other RWD cars I would have been walking it sideways down the road (which is fun, don't get me wrong - when I want). Not to keep the back and forth going here, but I can't see why you would want to turn off VDC (under normal driving, ie: not playing/racing), isn't it designed to keep you on the road as safe as possible within limits of course?
In my other RWD cars I would have been walking it sideways down the road (which is fun, don't get me wrong - when I want). Not to keep the back and forth going here, but I can't see why you would want to turn off VDC (under normal driving, ie: not playing/racing), isn't it designed to keep you on the road as safe as possible within limits of course?
#33
07-12-2005, 07:40 PM
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The kids were seen speeding and cutting in and out of traffic in the rain. Sorry there. How fast and whether the VDC was on or not is not important and not what I am trying to get at. Just wanted to share that news.
But IMO. Driving any rear wheel drive vehicle with power is all about throttle control. The point is that with VDC "on" a driver will not learn to use the throttle properly. With it off a driver can appreciate and learn how to control the power with the throttle.
Accidental spinouts with rear wheel drive cars in the rain are mainly (not always) caused by people jabbing the throttle in a turn. Enter a corner too hot you simply understeer into the curb. Avoiding the first is a matter of habit and training. The latter happens when the driver is not familar with the road or his/her car's limits.
If the driver is accustomed to feathering the throttle by training with the VDC off then he/she would know how to "drive" the car in any weather at the traction limit of the rear tires at any speeds. Something you cannot do with the VDC on.
So the point I am trying to make is that: if the driver drives with the VDC off, he would know the limit of his car and wouldn't drive way too fast to being with.
Madchef: my opinion about hydroplaning and VDC is not confirmation for why I "total agree" on having the VDC off in the rain. That's why it's written in a separate paragraph with a different heading.
More thoughts on this... We normally brace for the wheel and pull to the left slightly if we are about to run onto a large puddle on the right side. At lower speeds the puddle will pull the car to the right. But at higher speeds how does the steering feel? Does the puddle still pull you to the right?
But IMO. Driving any rear wheel drive vehicle with power is all about throttle control. The point is that with VDC "on" a driver will not learn to use the throttle properly. With it off a driver can appreciate and learn how to control the power with the throttle.
Accidental spinouts with rear wheel drive cars in the rain are mainly (not always) caused by people jabbing the throttle in a turn. Enter a corner too hot you simply understeer into the curb. Avoiding the first is a matter of habit and training. The latter happens when the driver is not familar with the road or his/her car's limits.
If the driver is accustomed to feathering the throttle by training with the VDC off then he/she would know how to "drive" the car in any weather at the traction limit of the rear tires at any speeds. Something you cannot do with the VDC on.
So the point I am trying to make is that: if the driver drives with the VDC off, he would know the limit of his car and wouldn't drive way too fast to being with.
Madchef: my opinion about hydroplaning and VDC is not confirmation for why I "total agree" on having the VDC off in the rain. That's why it's written in a separate paragraph with a different heading.
More thoughts on this... We normally brace for the wheel and pull to the left slightly if we are about to run onto a large puddle on the right side. At lower speeds the puddle will pull the car to the right. But at higher speeds how does the steering feel? Does the puddle still pull you to the right?
#34
07-12-2005, 07:56 PM
Originally Posted by clinty
Consider a scenario where you are powering through in the rain and one side of the car, say the right side, hits a long puddle of water and hydroplanes. The right side has little to no traction and your rear wheel starts to spin (just a little more than the left even if you have LSD). Now your VDC reacts and cuts the power (and depending on the circumstances the brakes might be applied by the VDC too). Your left wheels, which are in full contact and traction with the pavement, are now engine braking because of the VDC. Remember that the right wheels has no traction. This in itself may not result in a spin depend on the road (straight, left or right curve) But its motion might cause some knee-jerk reaction in the driver to try and maintain control and lose control.
If you have traction control, the ECU will apply the brakes onto the tire that is spinning faster. The reason it does this, is that it is trying to slow the tire down, such that the other tire will spin faster, and get the power from the differential.
I saw a very good demo on this, (Electronic Stability Control), at the Deutche Museum when I was in Munich. It explained how in this particular scenario, it would be impossible for the car to ascend the hill without traction control. And that's what happened in the demo. With TracOff, the car just slid backwards. With TracOn, it ascended the hill.
With that being said, if one of your tires hits the puddle as you describe, and that tire loses traction, that wheel will spin faster, since it has no traction. The brakes will be applied to that wheel, not the one with full traction.
Engine power reduction is a last resort effort, not a first option response. Because, applying the brakes to particular wheels, can shift the vehicles momentum, to try to regain control. That doesn't happen when you just reduce power. The ECU will reduce power if none of the brakes is affecting your trajectory, (prob because you have no traction anywhere), so reducing power to lower you velocity in hopes that one of the wheels will "catch".
If leaving the VDC on would really cause you to lose control of your car in rainy situations, no auto manufacturer in the world would take on that kind of liability by offering that "safety device", as standard equipment.
Last edited by avs007; 07-12-2005 at 07:58 PM.
#35
07-12-2005, 08:26 PM
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Whether or not the brake or throttle is the first to be controlled will depend on the situation and VDC programming.
Traction control is different from VDC. You are right though. traction control will brake the spinning wheel. [side note: it does not transfer power from the spinning wheel to the one that is not spinning. It only keeps a certain gear in the differential from spinning so that the same power can be applied at both wheels. (hmm may have more explaining to do here).] This only limits single wheel spin and in some cars, even the lesser models of our G, is what they call it electronic limited slip differential.
I do not know if our G's have all the VDC features. But advanced VDC's can make use of brakes (at any wheel, do we have 4 channel brakes?) or cut the throttle down or brake and power the rear wheels at the same time. VDC measures the motions of our car (yaw rates, side G's, acceleration, etc) to sense the dynamics of the vehicle and control if need be. So it is much much more sophisticated than just traction control.
If you have a 6mt. Try jabbing the throttle in a slow turn with the VDC on. You can floor the thing and your car will not fish tale or accelerate. But at the same time it won't decelerate due to braking (you will slow down because of turning friction/drag though).
The scenario I posted is just for thought and discussion. It is not meant to say that VDC is unsafe in that situation.
Traction control is different from VDC. You are right though. traction control will brake the spinning wheel. [side note: it does not transfer power from the spinning wheel to the one that is not spinning. It only keeps a certain gear in the differential from spinning so that the same power can be applied at both wheels. (hmm may have more explaining to do here).] This only limits single wheel spin and in some cars, even the lesser models of our G, is what they call it electronic limited slip differential.
I do not know if our G's have all the VDC features. But advanced VDC's can make use of brakes (at any wheel, do we have 4 channel brakes?) or cut the throttle down or brake and power the rear wheels at the same time. VDC measures the motions of our car (yaw rates, side G's, acceleration, etc) to sense the dynamics of the vehicle and control if need be. So it is much much more sophisticated than just traction control.
If you have a 6mt. Try jabbing the throttle in a slow turn with the VDC on. You can floor the thing and your car will not fish tale or accelerate. But at the same time it won't decelerate due to braking (you will slow down because of turning friction/drag though).
The scenario I posted is just for thought and discussion. It is not meant to say that VDC is unsafe in that situation.
#36
07-12-2005, 08:50 PM
All I know is this...if Infiniti made a stability system which got you into a accident versus you not having it, they would have a very big problem on their hands.
I also know another thing...the engineers at Nissan are probably a hell of a lot smarter than I am and I think I'll just let the computer do it's thing.
Note: I don't know anything about keeping VDC on of off nor do I prefer one or the other. I'm just saying what makes sense to me. I'd be hard-pressed to believe they didn't test VDC in the rain and even if it was proven to be worse, for them not to give some sort of warning to owners (maybe in the manual). That's like asking for Nissan to go bankrupt from distrust and lawsuits. I mean heck, they have labels telling us coffee is hot, be careful now.
I also know another thing...the engineers at Nissan are probably a hell of a lot smarter than I am and I think I'll just let the computer do it's thing.
Note: I don't know anything about keeping VDC on of off nor do I prefer one or the other. I'm just saying what makes sense to me. I'd be hard-pressed to believe they didn't test VDC in the rain and even if it was proven to be worse, for them not to give some sort of warning to owners (maybe in the manual). That's like asking for Nissan to go bankrupt from distrust and lawsuits. I mean heck, they have labels telling us coffee is hot, be careful now.
#37
07-12-2005, 09:10 PM
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Originally Posted by 94gxe
If y ou are driving on High Performance tires you will have trouble with rain and snow. They are designed for dry roads. Get some of the top rated All Seasons - Bridgestone RE950, Turanza, any of the top 5 listed in the Tire Rack survey and you should be okay. I'm on Bridgestone RE92, model before the RE950, with about 40K miles on them, live in the Seattle area and only have problems when the roads have standing water on them. Normal rain, all winter long, they are great.
#38
07-12-2005, 10:10 PM
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Originally Posted by rollover
Quick question on how the G coupe handles in the rain. I talked to a G35 sedan owner and he commented that the coupes his friends have handle like Mustangs in the rain and snow. The winter I'm not too worried about as that is why I am keeping my Avalanche but I would hate to buy a car that can only be driven on sunny dry days. Hell, may as well go with the Ultra at that point. Let me know how they handle in different weather situations.
#39
07-12-2005, 10:41 PM
#40
07-12-2005, 11:31 PM
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Here is a quote from the infiniti website on the VDC as well as a disclaimer at the bottom.
Quote:
"A sudden change in surface consistency can affect your car's stability during evasive maneuvering. Vehicle Dynamic Control* uses an array of sensors to help determine your steered path and to help keep you in control. If your vehicle begins to understeer (plow forward) or oversteer (fishtail), VDC applies appropriate brake pressure to individual wheels and/or reduces engine output to help keep both ends in line. Also, to help enhance rear-wheel grip when the G35 Coupe accelerates, Infiniti developed a Traction Control System that senses wheelspin and automatically reduces engine output to help give you a surer foothold.
*VDC cannot prevent accidents due to abrupt steering, carelessness, or dangerous driving techniques. Always drive safely."
Quote:
"A sudden change in surface consistency can affect your car's stability during evasive maneuvering. Vehicle Dynamic Control* uses an array of sensors to help determine your steered path and to help keep you in control. If your vehicle begins to understeer (plow forward) or oversteer (fishtail), VDC applies appropriate brake pressure to individual wheels and/or reduces engine output to help keep both ends in line. Also, to help enhance rear-wheel grip when the G35 Coupe accelerates, Infiniti developed a Traction Control System that senses wheelspin and automatically reduces engine output to help give you a surer foothold.
*VDC cannot prevent accidents due to abrupt steering, carelessness, or dangerous driving techniques. Always drive safely."
#41
07-13-2005, 12:05 AM
Originally Posted by avs007
That's not how VDC/Traction Control works. In a typical differential, the power always goes to the wheel that spins faster. If you drive with one wheel on ice, and the other on dry pavement, the tire that is on the ice, will just spin.
If you have traction control, the ECU will apply the brakes onto the tire that is spinning faster. The reason it does this, is that it is trying to slow the tire down, such that the other tire will spin faster, and get the power from the differential.
I saw a very good demo on this, (Electronic Stability Control), at the Deutche Museum when I was in Munich. It explained how in this particular scenario, it would be impossible for the car to ascend the hill without traction control. And that's what happened in the demo. With TracOff, the car just slid backwards. With TracOn, it ascended the hill.
With that being said, if one of your tires hits the puddle as you describe, and that tire loses traction, that wheel will spin faster, since it has no traction. The brakes will be applied to that wheel, not the one with full traction.
Engine power reduction is a last resort effort, not a first option response. Because, applying the brakes to particular wheels, can shift the vehicles momentum, to try to regain control. That doesn't happen when you just reduce power. The ECU will reduce power if none of the brakes is affecting your trajectory, (prob because you have no traction anywhere), so reducing power to lower you velocity in hopes that one of the wheels will "catch".
If leaving the VDC on would really cause you to lose control of your car in rainy situations, no auto manufacturer in the world would take on that kind of liability by offering that "safety device", as standard equipment.
If you have traction control, the ECU will apply the brakes onto the tire that is spinning faster. The reason it does this, is that it is trying to slow the tire down, such that the other tire will spin faster, and get the power from the differential.
I saw a very good demo on this, (Electronic Stability Control), at the Deutche Museum when I was in Munich. It explained how in this particular scenario, it would be impossible for the car to ascend the hill without traction control. And that's what happened in the demo. With TracOff, the car just slid backwards. With TracOn, it ascended the hill.
With that being said, if one of your tires hits the puddle as you describe, and that tire loses traction, that wheel will spin faster, since it has no traction. The brakes will be applied to that wheel, not the one with full traction.
Engine power reduction is a last resort effort, not a first option response. Because, applying the brakes to particular wheels, can shift the vehicles momentum, to try to regain control. That doesn't happen when you just reduce power. The ECU will reduce power if none of the brakes is affecting your trajectory, (prob because you have no traction anywhere), so reducing power to lower you velocity in hopes that one of the wheels will "catch".
If leaving the VDC on would really cause you to lose control of your car in rainy situations, no auto manufacturer in the world would take on that kind of liability by offering that "safety device", as standard equipment.
Okay mc2 and madchef, Take a good look at this
Drink it in, Because this is how nice people explain things. Instead of instantly shoving your opinon down my throat and turning it into a pissing contest, You could just Explan it in a nice, calm, non condensading (sp?) way!
I completely agree with you, Despite my limited rain XP and tring it both on and off in VERY heavy rain. I can agree with a well put statement like that! And i'll probably leave it on the next time I drive.
#42
07-13-2005, 01:15 AM
okay.. i been reading this thread and i just had my G for about 3 months now never knew what VDC was, well i did but i always left it on. So tell me this with VDC off its more funner to drive, yes i know that. But wen you start to understeer how do you control it? i tested it out going on a curve at bout 85-90 mph it started to understeer so all i did was move the steering wheel more to the left and ease off the gas then at about 85 mph put my foot back on the gas.
#43
07-13-2005, 06:01 AM
Originally Posted by Jtrain
Okay mc2 and madchef, Take a good look at this
Drink it in, Because this is how nice people explain things. Instead of instantly shoving your opinon down my throat and turning it into a pissing contest, You could just Explan it in a nice, calm, non condensading (sp?) way!
I completely agree with you, Despite my limited rain XP and tring it both on and off in VERY heavy rain. I can agree with a well put statement like that! And i'll probably leave it on the next time I drive.
Drink it in, Because this is how nice people explain things. Instead of instantly shoving your opinon down my throat and turning it into a pissing contest, You could just Explan it in a nice, calm, non condensading (sp?) way!
I completely agree with you, Despite my limited rain XP and tring it both on and off in VERY heavy rain. I can agree with a well put statement like that! And i'll probably leave it on the next time I drive.
Jtrain, you remind me a lot like another little 16 year old boy that would cry every time he got owned. I bet you're around his age:
his name is WizzatheL337, o yea it's spelled 'condescending' btw
-----
Leave the VDC on in the rain for safety, unless you're out to have a little fun. Just keep it safe and we're all good.
PS. to the owner who got the almighty Bridgestone Potenza RE92's, haha trust me when I say they're no good, either in rain or dry ground. I had them as stockers on my WRX. Pretty horrible tires. Stock Pilots on the G 03/04's and stock Bridgestone RE9050 on the 6MT 05's are far superior tires.
Last edited by iampaul; 07-13-2005 at 06:04 AM.
#44
07-13-2005, 07:36 AM
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#45
07-13-2005, 09:55 AM
Originally Posted by Jtrain
Instead of instantly shoving your opinon down my throat and turning it into a pissing contest, You could just Explan it in a nice, calm, non condensading (sp?) way!
Originally Posted by Jtrain
If you turn off your VCD in the rain your fine, but MAKE SURE YOU DO, or you may die.