She's acting up....

370Zsteve · 02-20-2010, 01:45 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

KillerBee370 · 02-20-2010, 01:45 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, 01:50 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.

speedworks · 02-20-2010, 01:52 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.

370Zsteve · 02-20-2010, 01:54 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............

speedworks · 02-20-2010, 01:58 PM

Quote:

Originally Posted by 370Zsteve

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............

If you are accelerating into a turn, you are going to slow. I come into them at speed, brake initially, turn in, slight throttle if needed, and then you are at the edge of a spin/drift, and at the point, I will lift and ride it out a little (sometimes longer since MA doesn't develop on/off ramps well, and they become a decreasing radius), and that is when you will feel it. I am always in the sweet spot of the particular gear (usually 3rd). Steve, if you are ever in the Providence/Boston area, let me know, I will show you it.

fullmonty · 02-20-2010, 04:31 PM

Quote:

Originally Posted by dszombiex

Well this past weekend when I was coasting downhill in full auto mode with my foot completely off the throttle, the car suddenly revved twice! It was a decent rev too like up to 4k or something. I drive in full auto mode when I'm lazy or during my daily commute to work all the time. Its never gone off in full auto mode before.

Same with my 7AT, was going down a fairly step hill, foot off the gas just kind of coasting down at aprox. 40-45mph, the car downshifted but held the RPM at 4k. Didn't feel an increase in speed or anything, just held at 4k until I breaked. Took me by suprise but I don't think it's anything to worry about.

speedworks · 02-22-2010, 03:09 PM

UPDATE: Just took it to the dealer, and was able to re-enact the issue with a tech in the car. One thing I didn't think about was putting my foot in the clutch when it happens. He suggested it, and what do you know, the car went to 4500 rpm and maintained that rpm through the turn (or until I touched the brake or the turn straightened out). So, it was definately maintaining a throttle. Those with this issue should try the same thing. Anyway, the car is in their hands now; and hopefully they call with a option/solution.

Premo34WV · 02-22-2010, 03:39 PM

glad to hear this was reenacted with the dealer present. Please update us as this is still happening to me. And i agree it only happens at the "sweet spot" of the gear.

speedworks · 02-23-2010, 07:38 PM

Quick update:
They couldn't find any obvious issue to cause the problem (checked all wiring and sensors, and found nothing). They have a call into Engineering, and are awaiting an answer of what to do next - they will have the car for a few more days. Its supposed to rain around here the rest of the week, so no biggie for me.

I also put in a complaint on the PW sideskirts not being a perfect paint fit (like all of them). Again, they will be reviewed by a corp representative when they are back in town (the run around on that one).

speedworks · 02-25-2010, 06:56 PM

Well, they called today, and said I can pick it up. The dealer said that Engineering (Nissan) came back saying they are working on it, and will let me (the dealer) know when they have a fix - timing unknown.

Hmmm, disappointing.

BoostAddict · 02-25-2010, 07:17 PM

Quote:

Originally Posted by speedworks

Well, they called today, and said I can pick it up. The dealer said that Engineering (Nissan) came back saying they are working on it, and will let me (the dealer) know when they have a fix - timing unknown.

Hmmm, disappointing.

They, Nissan Engineering, probably have to modify their algorithm used for SRM. Maybe/Hopefully enough people will complain about this issue to have it escalated so a fix (in the form of a TSB) can be pushed out sooner rather than later.

I wouldn't hold my breath in hopes of a fix to be released soon though. When they do develop a fix, it will have to go through extensive (read long) testing.

davidyan · 02-26-2010, 12:12 AM

Quote:

Originally Posted by noodles

i have heard of this before and more then likely what causes it is the that the rev match is designed so that when you downshift your going to be right back on the gas so it anticipates this and does it for you.

This ^^ sounds like a pretty logical explanation... Also notice that if you are cruising then move into neutral, when the snychro rev match kicks in (immediately), that it holds the revs for a long time before realizing that you are not moving into another gear (due to coasting in neutral) and then slowly allows itself to wind down. Thus, if you were to downshift and not manully get back on the gas, the synchro rev match is still electronically holding the throttle open for about 3 seconds or so. Because of this, any engine braking would be minimal, if any during that time period. One way to test would be to disable the syncro-rev match and try it again- you would engine brake much harder then.

IMWEZL · 02-26-2010, 04:03 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, 08:07 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).

02-20-2010, 01:45 PM	#17 (permalink)
KillerBee370 A True Z Fanatic Join Date: Mar 2009 Location: So Cal baby! Age: 52 Posts: 5,964 Drives: with passion Rep Power: 321	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.

02-22-2010, 03:09 PM	#23 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 18	UPDATE: Just took it to the dealer, and was able to re-enact the issue with a tech in the car. One thing I didn't think about was putting my foot in the clutch when it happens. He suggested it, and what do you know, the car went to 4500 rpm and maintained that rpm through the turn (or until I touched the brake or the turn straightened out). So, it was definately maintaining a throttle. Those with this issue should try the same thing. Anyway, the car is in their hands now; and hopefully they call with a option/solution.

02-22-2010, 03:39 PM	#24 (permalink)
Premo34WV Base Member Join Date: Jun 2009 Location: Morgantown, W.Virginia Posts: 68 Drives: PW '09 370z Sp. 6mt Rep Power: 16	glad to hear this was reenacted with the dealer present. Please update us as this is still happening to me. And i agree it only happens at the "sweet spot" of the gear.

02-23-2010, 07:38 PM	#25 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 18	Quick update: They couldn't find any obvious issue to cause the problem (checked all wiring and sensors, and found nothing). They have a call into Engineering, and are awaiting an answer of what to do next - they will have the car for a few more days. Its supposed to rain around here the rest of the week, so no biggie for me. I also put in a complaint on the PW sideskirts not being a perfect paint fit (like all of them). Again, they will be reviewed by a corp representative when they are back in town (the run around on that one).

02-25-2010, 06:56 PM	#26 (permalink)
speedworks Track Member Join Date: Jan 2009 Location: Boston, MA Posts: 550 Drives: PW purchased 01/09 Rep Power: 18	Well, they called today, and said I can pick it up. The dealer said that Engineering (Nissan) came back saying they are working on it, and will let me (the dealer) know when they have a fix - timing unknown. Hmmm, disappointing.

02-26-2010, 04:03 AM	#29 (permalink)
IMWEZL Track Member Join Date: Apr 2009 Location: HNL Posts: 603 Drives: 370Z/MKVII GTI Rep Power: 17	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, 08:07 AM	#30 (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).