She's acting up....

speedworks · 02-20-2010, 09:05 AM

Quote:

Originally Posted by Pharmacist

I read that porsche has a feature called engine torque drag control or something like that as part of the porsche stability management program. What it does apparently is that it opens the throttle a bit so that the engine revving down doesn't rev down too quickly and cause too much drag on the rear wheels and break their traction and lead to spinning out. Perhaps the Z stability control has a similar feature?

What I am having happen is definately not a 'wanted' feature. And it doesn't rev down at all (maintains rpm), until either the turn increases radius (less g force) or I touch the brakes. Thanks though.

Zeto · 02-20-2010, 10:01 AM

Very interesting. I have come across the same thing and thought it was just a placebo effect but it's just as speed works has described.

speedworks · 02-20-2010, 10:07 AM

Yeah, you won't notice it, unless you are daring enough/experienced enough to take a turn at a significant speed. On a racetrack, I would feel this constanty. I scare my passengers every time I do it, but the issue I feel, scares me sometimes, and it isn't what a car is supposed to do.

370Zsteve · 02-20-2010, 12:45 PM

Quote:

Originally Posted by speedworks

Yeah, you won't notice it, unless you are daring enough/experienced enough to take a turn at a significant speed. On a racetrack, I would feel this constanty. I scare my passengers every time I do it, but the issue I feel, scares me sometimes, and it isn't what a car is supposed to do.

I'll never feel it because I always downshift and accelerate into off-ramps

speedworks · 02-20-2010, 12:50 PM

Quote:

Originally Posted by 370Zsteve

I'll never feel it because I always downshift and accelerate into off-ramps

Yeah, I accelerate out of the turn too, but I am talking going into the turn. If you are accelerating, in my situation, you will spin it. Again, momentum is not it, I can get it to do it for seconds on a long speeding turn.

370Zsteve · 02-20-2010, 12:54 PM

Quote:

Originally Posted by speedworks

Yeah, I accelerate out of the turn too, but I am talking going into the turn. If you are accelerating, in my situation, you will spin it. Again, momentum is not it, I can get it to do it for seconds on a long speeding turn.

No, no, I downshift and hit the gas going into off-ramps. It's a game..... and I never get the issue you described. I never head into off-ramps without downshifting, I guess it's just me. This issue would also have a lot to do with what gear you were in, no? In 6th, I could see where it would feel like it wasn't slowing down............

bloodo · 02-20-2010, 12:27 PM

I think this is calls momentum. Unless you guys shift it to a very low gear, where the rpm needs to maintain the same speed is significantly more, then you will likely not see engine breaking just by lifting off the pedal. Example: just accelerate, downhill, level pavement, etc.

As speedworks described, he takes a turn at a significant speed, that speed will maintain because of the angular momentum. Not sure what gear he is normally in, but if taking a sharp turn at like 4th or 5th gear going 65mph, simply lifting of the gas pedal will not slow the car down because the rpm needs to maintain the speed is still low. This is just an example.

speedworks · 02-20-2010, 12:42 PM

Its not momentum, trust me, I have lots of experience at speed (on a track), and know how a car should feel/act in turns. The problem my car has, and I can assume others as well have, is that the car maintains a throttle in these situations. Its not normal, and hopefully I will be able to recreate it with a tech in the car. It does it for seconds in a long sweeping turn, so there is enough time for the car to slow (and when I say slow, I mean 1mph), you can hear the throttle (through the exhaust note not changing), until the situation changes (brakes or straightening) and then it releases the throttle. My guess is something with the g forces are causing a sensor to change.

KillerBee370 · 02-20-2010, 12:45 PM

Yes.. it's called momentum. It's also called a heavy flywheel coupled with the fact that the engine has rev-matched so the rpm's are a spinnin!

I still have this somewhat even with my lightweight flywheel but not nearly as much as the heavy stocker.

speedworks · 02-20-2010, 12:52 PM

Quote:

Originally Posted by KillerBee370

Yes.. it's called momentum. It's also called a heavy flywheel coupled with the fact that the engine has rev-matched so the rpm's are a spinnin!

I still have this somewhat even with my lightweight flywheel but not nearly as much as the heavy stocker.

Oh yeah, forgot to say, I don't use the SRM, so at the point this is happening, I am already in a gear (usually I am in 3rd at the time) for quite a few seconds.

IMWEZL · 02-26-2010, 03:03 AM

Yeah this is same thing I was trying to explain in the autocross thread. Weird and threw me off the first few times it happened. Now I just run the car with the SRM off without issues.

speedworks · 02-26-2010, 07:07 AM

^^^ Guys, I don't use the SRM - it is always off, so these explanations aren't in line with the situation. Also, this happens when the car is in gear already, not in neutral, or not in a position where any shifting is about to happen. It happens in gear, at fast speeds around turns. Definately a problem, they recognized that, but don't have a solution. What was interesting is when I did it with the tech in the car, and then put my foot in the clutch (no movement of the shifter), it moved the rpms to 4500, when at the time I was probably at around 4100-4200.

Those of you who noticed it in an autocross, take a long sweeping on/off ramp, at speed, in a single gear, take your foot off the gas (at the point you need to because you are bringing a lot of speed into the turn), and then you will feel the problem -feels like the gas is still on (steady, not increasing).

KingZee · 03-02-2010, 04:03 PM

I've had the car for a little over a month and have about 1600 miles on it. I've just started to push it after break-in and I noticed this for the first time yesterday going onto an on-ramp. I have the base model, no sports package, no sync rev, so that takes out sync rev as the culprit.

I was approaching the on ramp pretty fast in 3rd, I rev-matched and put it into second at about 4k rmp (possibly higher), the car was in gear before I took the turn and noticed it's not engine breaking for s***! I almost went into the f'ing curb and if I wasn't somewhat experienced I probably would have.

This being a heavy flywheel issue SOMEWHAT makes sense from the way it felt. Like the flywheel was spinning and because it's heavy its momentum kept carrying the gear? F! I don't f'in know.

speedworks · 03-03-2010, 09:44 PM

That's it. I would suspect quite a few people have it, they just haven't put the car into the situation. Please take it to the dealer, so there are more complaints to the problem. They supposedly give a case number by customer name (pm me if you want my name to reference). Obviously, they haven't come back with a solution yet.

labk888 · 03-03-2010, 10:48 PM

Quote:

Originally Posted by speedworks

That's it. I would suspect quite a few people have it, they just haven't put the car into the situation. Please take it to the dealer, so there are more complaints to the problem. They supposedly give a case number by customer name (pm me if you want my name to reference). Obviously, they haven't come back with a solution yet.

This is a cause of major concern for me as I was planning on picking a Z this weekend. Do you guys feel that the issues you are seeing are an isolated problem (lemon vehicle) or a general engineering problem that all cars have? Someone in this thread mentioned that this is happening to
their 1 month old car, which I presume is a 2010.

02-20-2010, 12:42 PM	#8 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 18	Its not momentum, trust me, I have lots of experience at speed (on a track), and know how a car should feel/act in turns. The problem my car has, and I can assume others as well have, is that the car maintains a throttle in these situations. Its not normal, and hopefully I will be able to recreate it with a tech in the car. It does it for seconds in a long sweeping turn, so there is enough time for the car to slow (and when I say slow, I mean 1mph), you can hear the throttle (through the exhaust note not changing), until the situation changes (brakes or straightening) and then it releases the throttle. My guess is something with the g forces are causing a sensor to change. Last edited by speedworks; 02-20-2010 at 12:45 PM.

03-02-2010, 04:03 PM	#13 (permalink)
KingZee A True Z Fanatic Join Date: Feb 2010 Location: Glendale, CA Age: 42 Posts: 2,612 Drives: Focus ST Rep Power: 424	I've had the car for a little over a month and have about 1600 miles on it. I've just started to push it after break-in and I noticed this for the first time yesterday going onto an on-ramp. I have the base model, no sports package, no sync rev, so that takes out sync rev as the culprit. I was approaching the on ramp pretty fast in 3rd, I rev-matched and put it into second at about 4k rmp (possibly higher), the car was in gear before I took the turn and noticed it's not engine breaking for s**! I almost went into the f'ing curb and if I wasn't somewhat experienced I probably would have. This being a heavy flywheel issue SOMEWHAT makes sense from the way it felt. Like the flywheel was spinning and because it's heavy its momentum kept carrying the gear? F! I don't f'in know. Last edited by KingZee; 03-02-2010 at 04:10 PM.*

02-20-2010, 10:01 AM	#2 (permalink)
Zeto Track Member Join Date: Apr 2009 Location: North NJ Age: 41 Posts: 766 Drives: 09 Pearl White 370Z Rep Power: 268	Very interesting. I have come across the same thing and thought it was just a placebo effect but it's just as speed works has described.

02-20-2010, 10:07 AM	#3 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 18	Yeah, you won't notice it, unless you are daring enough/experienced enough to take a turn at a significant speed. On a racetrack, I would feel this constanty. I scare my passengers every time I do it, but the issue I feel, scares me sometimes, and it isn't what a car is supposed to do.

02-20-2010, 12:27 PM	#7 (permalink)
bloodo Base Member Join Date: May 2009 Location: Nebraska Posts: 93 Drives: . Rep Power: 17	I think this is calls momentum. Unless you guys shift it to a very low gear, where the rpm needs to maintain the same speed is significantly more, then you will likely not see engine breaking just by lifting off the pedal. Example: just accelerate, downhill, level pavement, etc. As speedworks described, he takes a turn at a significant speed, that speed will maintain because of the angular momentum. Not sure what gear he is normally in, but if taking a sharp turn at like 4th or 5th gear going 65mph, simply lifting of the gas pedal will not slow the car down because the rpm needs to maintain the speed is still low. This is just an example.

02-20-2010, 12:45 PM	#9 (permalink)
KillerBee370 A True Z Fanatic Join Date: Mar 2009 Location: So Cal baby! Age: 52 Posts: 5,964 Drives: with passion Rep Power: 322	Yes.. it's called momentum. It's also called a heavy flywheel coupled with the fact that the engine has rev-matched so the rpm's are a spinnin! I still have this somewhat even with my lightweight flywheel but not nearly as much as the heavy stocker.

02-26-2010, 03:03 AM	#11 (permalink)
IMWEZL Track Member Join Date: Apr 2009 Location: HNL Posts: 603 Drives: 370Z/MKVII GTI Rep Power: 18	Yeah this is same thing I was trying to explain in the autocross thread. Weird and threw me off the first few times it happened. Now I just run the car with the SRM off without issues.

02-26-2010, 07:07 AM	#12 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 18	^^^ Guys, I don't use the SRM - it is always off, so these explanations aren't in line with the situation. Also, this happens when the car is in gear already, not in neutral, or not in a position where any shifting is about to happen. It happens in gear, at fast speeds around turns. Definately a problem, they recognized that, but don't have a solution. What was interesting is when I did it with the tech in the car, and then put my foot in the clutch (no movement of the shifter), it moved the rpms to 4500, when at the time I was probably at around 4100-4200. Those of you who noticed it in an autocross, take a long sweeping on/off ramp, at speed, in a single gear, take your foot off the gas (at the point you need to because you are bringing a lot of speed into the turn), and then you will feel the problem -feels like the gas is still on (steady, not increasing).

03-03-2010, 09:44 PM	#14 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 18	That's it. I would suspect quite a few people have it, they just haven't put the car into the situation. Please take it to the dealer, so there are more complaints to the problem. They supposedly give a case number by customer name (pm me if you want my name to reference). Obviously, they haven't come back with a solution yet.