ACD...friend or foe? (story)
Dec 26, 2005, 02:20 PM
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ACD...friend or foe? (story)
hey all,
okay, so here i am, coming off of the highway onto an onramp, and i'm going about 65 in 5th. car feels great, so i drop it into 4th and give it a little gas to see if she can take it. well after a few seconds of high speed turning, i can feel the car start to slip...so i ease off the throttle, probably a little too fast :/
*** kicks out, and i find myself spinning down an off ramp with drops on both sides and light poles galore. i obviously didnt mean to lose control, but was amazingly impressed with how easy it was to control the spin. i looked where i wanted to go, and spun another time and a half before finally stopping in the middle without hitting anything, and no damage to any parts except some smoke from my tires.
the lesson i learned was not to try and push the car on the street, and the cold weather (even though it was dry) doesnt help.
my question is regarding the ACD...i had it on gravel mode, and from what i understand it will lock the diff for 2-3 seconds in that mode. it was about that long until i lost control, and i find myself wondering if i had it in tarmac or snow if i would have been able to keep it from spinning. in tarmac i would have felt the push earlier, since the diff unlocks when you turn the wheel, and if it would have stayed locked a second or so more in snow mode i might have completed the turn. all feedback is welcome, as is any personal experiences. thank you.
btw. there are no suspension mods with the exception of a rear strut brace.
okay, so here i am, coming off of the highway onto an onramp, and i'm going about 65 in 5th. car feels great, so i drop it into 4th and give it a little gas to see if she can take it. well after a few seconds of high speed turning, i can feel the car start to slip...so i ease off the throttle, probably a little too fast :/
*** kicks out, and i find myself spinning down an off ramp with drops on both sides and light poles galore. i obviously didnt mean to lose control, but was amazingly impressed with how easy it was to control the spin. i looked where i wanted to go, and spun another time and a half before finally stopping in the middle without hitting anything, and no damage to any parts except some smoke from my tires.
the lesson i learned was not to try and push the car on the street, and the cold weather (even though it was dry) doesnt help.
my question is regarding the ACD...i had it on gravel mode, and from what i understand it will lock the diff for 2-3 seconds in that mode. it was about that long until i lost control, and i find myself wondering if i had it in tarmac or snow if i would have been able to keep it from spinning. in tarmac i would have felt the push earlier, since the diff unlocks when you turn the wheel, and if it would have stayed locked a second or so more in snow mode i might have completed the turn. all feedback is welcome, as is any personal experiences. thank you.
btw. there are no suspension mods with the exception of a rear strut brace.
Dec 26, 2005, 02:24 PM
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I always am amazed that someone can drive 65, give it gas, so lets say 70-75, spin out on an on ramp and not hit something. The onramps here in NY if you did that you would bounce off about 4 guard rails before you finally stopped.
Dec 26, 2005, 02:25 PM
#3
Was it raining or gravelly? Why did you have it in Gravel Mode?
Anyway, you got it backwards. In Tarmac mode, the diff locks immediately, but in Gravel and Snow, the diff does not lock right away. It takes longer to lock with each successive change down the line to Tarmac -> Gravel -> Snow. I don't think ACD had anything to do with you losing the rear, though. Anyone disagree?
Anyway, you got it backwards. In Tarmac mode, the diff locks immediately, but in Gravel and Snow, the diff does not lock right away. It takes longer to lock with each successive change down the line to Tarmac -> Gravel -> Snow. I don't think ACD had anything to do with you losing the rear, though. Anyone disagree?
Dec 26, 2005, 02:29 PM
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Originally Posted by aberabee
hey all,
push the car on the street, and the cold weather (even though it was dry) doesnt help.
i had it on gravel mode
push the car on the street, and the cold weather (even though it was dry) doesnt help.
i had it on gravel mode
Dec 26, 2005, 02:32 PM
#5
Seems like its a pretty obviously lift throttle oversteer to me.
Plus cold weather and road surface + Summer Tire Advans.
Plus cold weather and road surface + Summer Tire Advans.
Last edited by 2GDSM; Dec 26, 2005 at 02:37 PM.
Dec 26, 2005, 02:34 PM
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wow! so it seems i have my information backwards...i always thought the different modes kept the ACD *locked* longer, giving more traction and control...are you guys saying i have less control when it is locked up? based on what i thought i knew, i would keep it on gravel on cold days that might disguise black ice or just plain slippery roads. the roads were clear that day, just cold.
when i think of a diff being locked, it is distributing power to all both sides equally, but compromises turning ability. to me it made sense that in adverse weather you would want the diff to be locked so the car is more predictable, as opposed to each wheel spinning at its own leisure. thanks!
when i think of a diff being locked, it is distributing power to all both sides equally, but compromises turning ability. to me it made sense that in adverse weather you would want the diff to be locked so the car is more predictable, as opposed to each wheel spinning at its own leisure. thanks!
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Dec 26, 2005, 02:41 PM
#9
Originally Posted by Warrtalon
Was it raining or gravelly? Why did you have it in Gravel Mode?
Anyway, you got it backwards. In Tarmac mode, the diff locks immediately, but in Gravel and Snow, the diff does not lock right away. It takes longer to lock with each successive change down the line to Tarmac -> Gravel -> Snow. I don't think ACD had anything to do with you losing the rear, though. Anyone disagree?
Anyway, you got it backwards. In Tarmac mode, the diff locks immediately, but in Gravel and Snow, the diff does not lock right away. It takes longer to lock with each successive change down the line to Tarmac -> Gravel -> Snow. I don't think ACD had anything to do with you losing the rear, though. Anyone disagree?
J/K Happy Holidays to you and the fam!
Dec 26, 2005, 02:43 PM
#10
Originally Posted by aberabee
after a few seconds of high speed turning, i can feel the car start to slip...so i ease off the throttle
Yes, as said above, you experienced lift throttle oversteer. 911 owners are very familiar with this
Lifting off the gas mid-turn can cause numerous problems.
Dec 26, 2005, 02:55 PM
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Hmm yea I didn't think AWD helped you when out of control in a turn, but your know how of driving does.
I only see AWD in this car working say when I floor a turn from a stop and get the car sideways and feel how the car snaps back really hard and keeps you going straight again. I would expect AWD to also only be noticeable when flooring it through a hard turn on a track.
Correct me if I'm wrong, but if your not gasing through a big turn it wouldn't matter if the car had AWD,FWD,RWD its just that AWD has the ability to not slip while accelerating through the turn.
I only see AWD in this car working say when I floor a turn from a stop and get the car sideways and feel how the car snaps back really hard and keeps you going straight again. I would expect AWD to also only be noticeable when flooring it through a hard turn on a track.
Correct me if I'm wrong, but if your not gasing through a big turn it wouldn't matter if the car had AWD,FWD,RWD its just that AWD has the ability to not slip while accelerating through the turn.
Last edited by el producto; Dec 26, 2005 at 02:57 PM. Reason: sp*
Dec 26, 2005, 03:00 PM
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In a FWD or AWD car, I would countersteer and give more throttle if the rear was coming around. The front will help *pull* you out of the oversteer situation.
Never unsettle the car while turning, especially when you are "on the edge", doesn't matter what xWD your car is.
Never unsettle the car while turning, especially when you are "on the edge", doesn't matter what xWD your car is.
Dec 26, 2005, 03:06 PM
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Originally Posted by infin|ty
I always am amazed that someone can drive 65, give it gas, so lets say 70-75, spin out on an on ramp and not hit something. The onramps here in NY if you did that you would bounce off about 4 guard rails before you finally stopped.
Dec 27, 2005, 06:23 AM
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Originally Posted by Warrtalon
Was it raining or gravelly? Why did you have it in Gravel Mode?
Anyway, you got it backwards. In Tarmac mode, the diff locks immediately, but in Gravel and Snow, the diff does not lock right away. It takes longer to lock with each successive change down the line to Tarmac -> Gravel -> Snow. I don't think ACD had anything to do with you losing the rear, though. Anyone disagree?
Anyway, you got it backwards. In Tarmac mode, the diff locks immediately, but in Gravel and Snow, the diff does not lock right away. It takes longer to lock with each successive change down the line to Tarmac -> Gravel -> Snow. I don't think ACD had anything to do with you losing the rear, though. Anyone disagree?
Actually you have it backwards Wartalon...
Tarmac is the setting to be used in dry, paved conditions. In this setting, the ACD will almost immediately allow the center differential to go into a free state upon detecting a steering input. Additionally, this mode provides the strongest limited-slip clamping force of the three modes.