She's acting up....

speedworks · 06-12-2010, 01:58 PM

Update: heard nothing from the dealer, but had a theory that the stability control was causing this issue so I started to run without the stability control on. No stability control, no problem. So...the stability control was maintaining throttle in the turn - and that is the answer. I think the mapping is too conservative - but maybe for basic drivers it could save them from a spin. So now when I want to be real aggressive, I turn off the stability control (ironic).

PhoenixMr2 · 06-12-2010, 02:43 PM

I can't believe you guys haven't figured this out yet.

This is caused by the emissions standards we have in this country. Almost all DBW cars do this now. When moderately heavy on the gas if you suddenly come completely off the gas the car is tuned to burn off all the gas that has already been injected into the head/intake manifold (depending on car). It's not much gas, but it is plenty to maintain rpm's for a second or two or even to make the rpm's jump when the clutch is put in.

This has happened on every DBW car I have driven (that is fairly new). My '09 Wrangler does it, and I noticed it in a '08 WRX, a '07 Civic, and a Genesis Coupe I test drove. I didn't notice it when I drove the 370z, but it was a 40th edition and it only had 15 miles so I didn't want to ruin someones future baby by driving it hard.

Try loading up the engine in 5th gear with fairly heavy throttle then jump off the gas and wait for a second or so then put in the clutch... you should see the revs hang or possibly even jump.

Again, I've been told time and time again it is an emissions control device where the car burns off all the gas that has already been injected to avoid it just moving through the engine un-burned or partially burned and emitting worse emissions.

I'm sure if I could find some articles on it online somewhere (I seem to remember even edmunds mentioning it), but I'm heading out the door to visit family out of town. I'll post more info later

speedworks · 06-12-2010, 08:03 PM

Quote:

Originally Posted by PhoenixMr2

I can't believe you guys haven't figured this out yet.

This is caused by the emissions standards we have in this country. Almost all DBW cars do this now. When moderately heavy on the gas if you suddenly come completely off the gas the car is tuned to burn off all the gas that has already been injected into the head/intake manifold (depending on car). It's not much gas, but it is plenty to maintain rpm's for a second or two or even to make the rpm's jump when the clutch is put in.

This has happened on every DBW car I have driven (that is fairly new). My '09 Wrangler does it, and I noticed it in a '08 WRX, a '07 Civic, and a Genesis Coupe I test drove. I didn't notice it when I drove the 370z, but it was a 40th edition and it only had 15 miles so I didn't want to ruin someones future baby by driving it hard.

Try loading up the engine in 5th gear with fairly heavy throttle then jump off the gas and wait for a second or so then put in the clutch... you should see the revs hang or possibly even jump.

Again, I've been told time and time again it is an emissions control device where the car burns off all the gas that has already been injected to avoid it just moving through the engine un-burned or partially burned and emitting worse emissions.

I'm sure if I could find some articles on it online somewhere (I seem to remember even edmunds mentioning it), but I'm heading out the door to visit family out of town. I'll post more info later

These are not the symptoms. The car is inducing throttle in a turn for as long as it takes until the turn ends (not an emissions thing, but a stability control thing) to prevent any weight shifting. I was able to duplicate it at high speeds in turns (on/off ramps), with aggressive driving.

PhoenixMr2 · 06-12-2010, 08:29 PM

Just took the time to re-read what I posted this morning in a hurry, sorry if it came across as rude!!

That's an interesting thing about it only happening during a turn, must have missed that when reading the previous pages. It sounds similar though just only happening during a turn, really weird.

PhoenixMr2 · 06-12-2010, 08:32 PM

Just a thought, have you gone out to a large empty parking lot and induced this while just running a large circle and see how long it lasts? ...as in does it just maintain it for 30-40 seconds, or even more than a minute? Seems like a dangerous "feature"

Volcom370Z · 06-12-2010, 09:38 PM

Subscribed...

Just want to verify so I can try and replicate... high speed freeway exit (roundabout or what?) and downshift to a gear that will give me 4-5k of RPM, and let off the gas? This should cause me to keep accelerating or just get no engine braking?

speedworks · 06-12-2010, 10:08 PM

No, I haven't done it in a parking lot. Usually I can do it on an off or on ramp, usually I have been in 3rd gear, 4-5k rpm. Make sure you have some experience at that speed in a turn - I usually scare my passenger

I can make it last through a turn, about 5 seconds, but then the off/on ramp straightens out and then it decelerates like normal.

Honestly, when it first happens, it will scare the crap out of you, if you are entering the turn at high speeds (which is the requirement). I usually enter the turns at high speed, lift to scrub some speed off, and hope to accelerate out, but with the stability control on and when I take my foot off the pedal, it continues to drive - real freaky and uncomfortable. But, now I just turn off the stab. control.

ChrisSlicks · 06-13-2010, 10:03 AM

Quote:

Originally Posted by speedworks

No, I haven't done it in a parking lot. Usually I can do it on an off or on ramp, usually I have been in 3rd gear, 4-5k rpm. Make sure you have some experience at that speed in a turn - I usually scare my passenger

I can make it last through a turn, about 5 seconds, but then the off/on ramp straightens out and then it decelerates like normal.

Honestly, when it first happens, it will scare the crap out of you, if you are entering the turn at high speeds (which is the requirement). I usually enter the turns at high speed, lift to scrub some speed off, and hope to accelerate out, but with the stability control on and when I take my foot off the pedal, it continues to drive - real freaky and uncomfortable. But, now I just turn off the stab. control.

Yes those are the exact symptoms I have experienced. I was carrying partial throttle in the turn but with slight deceleration to increase turn in. The car decided that the throttle should be enough to maintain constant speed which is not what I wanted because the corner tightens slightly. I ended up having way more speed at the end of the corner than I wanted which was a little dangerous, fortunately I left a little on the table and was able to safely negotiate the corner, but this safety feature can be dangerous. I would like to know which elements trigger the stability program to intervene like that.

speedworks · 06-13-2010, 01:03 PM

^^ yeah, I don't think it was well thought out. I think it would work great for a car that had serious weight transfer problems during throttle lift at high rpm, but I don't think this car has that problem. It will eventually make someone wreck because of their response to the unexpected continuous stability control throttle. Oh well, now that I know, I turn it off.

Premo34WV · 06-14-2010, 09:00 AM

I never noticed the connection between stability control and this problem. I always assumed it was an SRM problem. Makes sense i guess. I usually do turn the stability control off, but sometimes i forget to push that button before the urge to push the car a bit. Ill pay attention to see if i can duplicate it with the stability control on and off.

Thanks for the updates.

LunaZ · 06-14-2010, 09:39 PM

Quote:

Originally Posted by Volcom370Z

Just want to verify so I can try and replicate... high speed freeway exit (roundabout or what?) and downshift to a gear that will give me 4-5k of RPM, and let off the gas? This should cause me to keep accelerating or just get no engine braking?

Quote:

Originally Posted by speedworks

Honestly, when it first happens, it will scare the crap out of you, if you are entering the turn at high speeds (which is the requirement). I usually enter the turns at high speed, lift to scrub some speed off, and hope to accelerate out, but with the stability control on and when I take my foot off the pedal, it continues to drive - real freaky and uncomfortable. But, now I just turn off the stab. control.

Quote:

Originally Posted by ChrisSlicks

Yes those are the exact symptoms I have experienced. I was carrying partial throttle in the turn but with slight deceleration to increase turn in. The car decided that the throttle should be enough to maintain constant speed which is not what I wanted because the corner tightens slightly. I ended up having way more speed at the end of the corner than I wanted which was a little dangerous, fortunately I left a little on the table and was able to safely negotiate the corner, but this safety feature can be dangerous. I would like to know which elements trigger the stability program to intervene like that.

Well, after reading this thread on Sunday morning, I experienced the exact thing you are describing in a fast, constant radius ramp where I downshifted from 6th to 5th and then 4th.
If it wasn't for this thread, would have been a bit unnerved seeing as I wasn't trying to recreate the scenario you've been describing and my car was hurtling towards slower moving traffic on the ramp. Instead I kind of chuckled and said to myself "how 'bout that?"
Another reason to turn the VDC off, I guess.

06-12-2010, 01:58 PM	#61 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 17	Update: heard nothing from the dealer, but had a theory that the stability control was causing this issue so I started to run without the stability control on. No stability control, no problem. So...the stability control was maintaining throttle in the turn - and that is the answer. I think the mapping is too conservative - but maybe for basic drivers it could save them from a spin. So now when I want to be real aggressive, I turn off the stability control (ironic).

06-12-2010, 02:43 PM	#62 (permalink)
PhoenixMr2 Base Member Join Date: May 2010 Location: Austin, TX Posts: 9 Drives: '15 WRX Rep Power: 14	I can't believe you guys haven't figured this out yet. This is caused by the emissions standards we have in this country. Almost all DBW cars do this now. When moderately heavy on the gas if you suddenly come completely off the gas the car is tuned to burn off all the gas that has already been injected into the head/intake manifold (depending on car). It's not much gas, but it is plenty to maintain rpm's for a second or two or even to make the rpm's jump when the clutch is put in. This has happened on every DBW car I have driven (that is fairly new). My '09 Wrangler does it, and I noticed it in a '08 WRX, a '07 Civic, and a Genesis Coupe I test drove. I didn't notice it when I drove the 370z, but it was a 40th edition and it only had 15 miles so I didn't want to ruin someones future baby by driving it hard. Try loading up the engine in 5th gear with fairly heavy throttle then jump off the gas and wait for a second or so then put in the clutch... you should see the revs hang or possibly even jump. Again, I've been told time and time again it is an emissions control device where the car burns off all the gas that has already been injected to avoid it just moving through the engine un-burned or partially burned and emitting worse emissions. I'm sure if I could find some articles on it online somewhere (I seem to remember even edmunds mentioning it), but I'm heading out the door to visit family out of town. I'll post more info later

06-12-2010, 08:29 PM	#64 (permalink)
PhoenixMr2 Base Member Join Date: May 2010 Location: Austin, TX Posts: 9 Drives: '15 WRX Rep Power: 14	Just took the time to re-read what I posted this morning in a hurry, sorry if it came across as rude!! That's an interesting thing about it only happening during a turn, must have missed that when reading the previous pages. It sounds similar though just only happening during a turn, really weird.

06-12-2010, 08:32 PM	#65 (permalink)
PhoenixMr2 Base Member Join Date: May 2010 Location: Austin, TX Posts: 9 Drives: '15 WRX Rep Power: 14	Just a thought, have you gone out to a large empty parking lot and induced this while just running a large circle and see how long it lasts? ...as in does it just maintain it for 30-40 seconds, or even more than a minute? Seems like a dangerous "feature"

06-12-2010, 09:38 PM	#66 (permalink)
Volcom370Z Base Member Join Date: Mar 2010 Location: Valencia, CA Posts: 236 Drives: 09 370Z Rep Power: 15	Subscribed... Just want to verify so I can try and replicate... high speed freeway exit (roundabout or what?) and downshift to a gear that will give me 4-5k of RPM, and let off the gas? This should cause me to keep accelerating or just get no engine braking?

06-12-2010, 10:08 PM	#67 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 17	No, I haven't done it in a parking lot. Usually I can do it on an off or on ramp, usually I have been in 3rd gear, 4-5k rpm. Make sure you have some experience at that speed in a turn - I usually scare my passenger I can make it last through a turn, about 5 seconds, but then the off/on ramp straightens out and then it decelerates like normal. Honestly, when it first happens, it will scare the crap out of you, if you are entering the turn at high speeds (which is the requirement). I usually enter the turns at high speed, lift to scrub some speed off, and hope to accelerate out, but with the stability control on and when I take my foot off the pedal, it continues to drive - real freaky and uncomfortable. But, now I just turn off the stab. control.

06-13-2010, 01:03 PM	#69 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 17	^^ yeah, I don't think it was well thought out. I think it would work great for a car that had serious weight transfer problems during throttle lift at high rpm, but I don't think this car has that problem. It will eventually make someone wreck because of their response to the unexpected continuous stability control throttle. Oh well, now that I know, I turn it off.

06-14-2010, 09:00 AM	#70 (permalink)
Premo34WV Base Member Join Date: Jun 2009 Location: Morgantown, W.Virginia Posts: 68 Drives: PW '09 370z Sp. 6mt Rep Power: 15	I never noticed the connection between stability control and this problem. I always assumed it was an SRM problem. Makes sense i guess. I usually do turn the stability control off, but sometimes i forget to push that button before the urge to push the car a bit. Ill pay attention to see if i can duplicate it with the stability control on and off. Thanks for the updates.