Question for 5AT owners!
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From: Salt Lake City, UT
Question for 5AT owners!
As of lately, I've discovered something in my '06 Enthusiast 5AT. At first, I thought it was kind of cool - that was three seconds after I did it. However, the fourth or fifth second after, I realized that it probably shouldn't do that. What happens is when I'm in standard drive mode (D), every once in a while when I tap the gas very quickly and swiftly, the motor will jump up to about 5,000 RPM and then drop before letting the transmission grab again. What's that about?
Well, my hypothesis is this. Due to the quickness of my foot when I do that, and how slightly I hit the pedal, I believe the car thinks I'm about to do a kick-down. Naturally, it will disengage the transmission and proceed to shift to a lower gear. However, it doesn't have time, because when it's about to shift, my foot's already off the gas. So, the RPMs lower to what they were, and the car continues driving in the previous gear. Personally, that's what I think. Of course, I also think I'm probably absolutely wrong. Anyone else got experience with this?
Well, my hypothesis is this. Due to the quickness of my foot when I do that, and how slightly I hit the pedal, I believe the car thinks I'm about to do a kick-down. Naturally, it will disengage the transmission and proceed to shift to a lower gear. However, it doesn't have time, because when it's about to shift, my foot's already off the gas. So, the RPMs lower to what they were, and the car continues driving in the previous gear. Personally, that's what I think. Of course, I also think I'm probably absolutely wrong. Anyone else got experience with this?
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From: Interwebz
I have hit the gas quickly while driving and yes, the RPM's will kickup and if I left off the gas that quickly thats all it will do. I believe its in the timing lag and the internals of the AT Tranny. It cannot play "catch-up" quick enough. Kinda sounds like you have a manual and have droped it into neutral and are reving. I try not to do it, usually happens when I see an opening to pass someone and then think twice or something deters me from flying by.
***Just a guess**
***Just a guess**
Last edited by trodis; Sep 25, 2007 at 10:39 AM.
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From: Salt Lake City, UT
Hah, so I was right! Thanks, guys. I did it the other day when I was in the car with my dad, just to see what he said. He was quite surprised and wondered how I did it without shifting into neutral. When I told him what it was (and I was right), he said that was ridiculous and that I should bring it to Nissan. Anyways, I won't do it anymore anyway, because it's kind of like confusing the car. The verdict here is that it's normal, but then again not a good idea. If you want to play with your RPMs, shift into neutral!
Let me just get something straight...the car goes to 5000RPM because you're stomping the pedal right? You said that you're quickly tapping the pedal and it does that. I assume you meant that when you floor it briefly, and let go it drops the revs a lot, and then picks them up again.
I mean, the engine revving to 5000RPM with a quick tap and back down isn't normal.
I mean, the engine revving to 5000RPM with a quick tap and back down isn't normal.
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Ok, I don't know if I am going to explain this completely right but am going to try. Rev matching in a manual is done when you are in a higher gear and going to shift into a lower gear. Obviously in a higher gear the rpm's are lower so when you are planning to down shift before putting it in the lower gear you slightly tap the gas pedal enough to raise the revs to match what they will be once you engage the lower gear to get a smoother shift and transition.
The newer Z's have rev matching technology built into them. So, when you slightly tap the gas it thinks you are going to downshift and raises the revs to match what gear it thinks you are going to shift into for a smoother shift.
Its completely normal and is designed that way. Nothing wrong with the car except adding a performance feature you don't need to work so hard to obtain in a completely manual way.
I am sure if I didn't explain that completely right others will correct me. Gets flame retardant suit on...
The newer Z's have rev matching technology built into them. So, when you slightly tap the gas it thinks you are going to downshift and raises the revs to match what gear it thinks you are going to shift into for a smoother shift.
Its completely normal and is designed that way. Nothing wrong with the car except adding a performance feature you don't need to work so hard to obtain in a completely manual way.
I am sure if I didn't explain that completely right others will correct me. Gets flame retardant suit on...
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From: San Francisco Bay Area
It's not rev-matching unless you are downshifting.
The 5AT will torque multiply in gears 1st through 3rd while upshifting and accelerating.
The proper way to upshift the 5AT is to shift with a level or accelerating throttle. This is opposite of what you would do in the 6MT. Don't lift off of the throttle while you are upshifting. You are not helping the transmission to shift and you are actually causing it to shift sloppy or slower because now the tranmission has to correct your error.
The Z's 5AT uses a torque converter. One of the advantages of using a torque converter is it's ability to convert excess velocity into more torque. The Z's TC can almost double the torque input from the engine to the driveshaft. Pro dragsters run 4x to 6x multiplication. A lot of people think that a torque converter loses power but they are actually wrong. A TC actually can create more power on the turbine side (driveshaft) than the impeller side is putting out (engine) as long as the impeller is spinning faster than the turbine. As the impeller and turbine approach similar speeds the TC will begin return the torque for more velocity until it fluid couples. Fluid coupling is not quite as efficient as using a mechanical clutch so the 5AT uses a mechanical lock-up clutch in the 1:1 (4th) and overdrive (5th) gear to achieve the same efficiency as the 6MT. When you shift aggressively and properly in the first three gears it will feel like the transmission didn't engage when in fact it hooked up in less than 200ms. During torque multiplication the impeller will be spinning faster than the turbine and it will feel like it didn't shift until the transmission couples or locks. The RPMs will be up on the engine while torque multiplying. While torque multiplying the stator is returning excess fluid back to the impeller so that it can be re-accelerated back to the turbine until the velocity of the impeller and turbine are almost equal.
http://www.acceleratorhighstall.com....rters_work.htm
http://www.acceleratorhighstall.com....ter_torque.htm
The 5AT will torque multiply in gears 1st through 3rd while upshifting and accelerating.
The proper way to upshift the 5AT is to shift with a level or accelerating throttle. This is opposite of what you would do in the 6MT. Don't lift off of the throttle while you are upshifting. You are not helping the transmission to shift and you are actually causing it to shift sloppy or slower because now the tranmission has to correct your error.
The Z's 5AT uses a torque converter. One of the advantages of using a torque converter is it's ability to convert excess velocity into more torque. The Z's TC can almost double the torque input from the engine to the driveshaft. Pro dragsters run 4x to 6x multiplication. A lot of people think that a torque converter loses power but they are actually wrong. A TC actually can create more power on the turbine side (driveshaft) than the impeller side is putting out (engine) as long as the impeller is spinning faster than the turbine. As the impeller and turbine approach similar speeds the TC will begin return the torque for more velocity until it fluid couples. Fluid coupling is not quite as efficient as using a mechanical clutch so the 5AT uses a mechanical lock-up clutch in the 1:1 (4th) and overdrive (5th) gear to achieve the same efficiency as the 6MT. When you shift aggressively and properly in the first three gears it will feel like the transmission didn't engage when in fact it hooked up in less than 200ms. During torque multiplication the impeller will be spinning faster than the turbine and it will feel like it didn't shift until the transmission couples or locks. The RPMs will be up on the engine while torque multiplying. While torque multiplying the stator is returning excess fluid back to the impeller so that it can be re-accelerated back to the turbine until the velocity of the impeller and turbine are almost equal.
http://www.acceleratorhighstall.com....rters_work.htm
http://www.acceleratorhighstall.com....ter_torque.htm
Last edited by Aggro_Al; Sep 26, 2007 at 12:18 AM.
350Z-holic
Joined: Mar 2007
Posts: 6,912
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From: Interwebz
Originally Posted by Aggro_Al
It's not rev-matching unless you are downshifting.
The 5AT will torque multiply in gears 1st through 3rd while upshifting and accelerating.
The proper way to upshift the 5AT is to shift with a level or accelerating throttle. This is opposite of what you would do in the 6MT. Don't lift off of the throttle while you are upshifting. You are not helping the transmission to shift and you are actually causing it to shift sloppy or slower because now the tranmission has to correct your error.
The Z's 5AT uses a torque converter. One of the advantages of using a torque converter is it's ability to convert excess velocity into more torque. The Z's TC can almost double the torque input from the engine to the driveshaft. Pro dragsters run 4x to 6x multiplication. A lot of people think that a torque converter loses power but they are actually wrong. A TC actually can create more power on the turbine side (driveshaft) than the impeller side is putting out (engine) as long as the impeller is spinning faster than the turbine. As the impeller and turbine approach similar speeds the TC will begin return the torque for more velocity until it fluid couples. Fluid coupling is not quite as efficient as using a mechanical clutch so the 5AT uses a mechanical lock-up clutch in the 1:1 (4th) and overdrive (5th) gear to achieve the same efficiency as the 6MT. When you shift aggressively and properly in the first three gears it will feel like the transmission didn't engage when in fact it hooked up in less than 200ms. During torque multiplication the impeller will be spinning faster than the turbine and it will feel like it didn't shift until the transmission couples or locks. The RPMs will be up on the engine while torque multiplying. While torque multiplying the stator is returning excess fluid back to the impeller so that it can be re-accelerated back to the turbine until the velocity of the impeller and turbine are almost equal.
http://www.acceleratorhighstall.com....rters_work.htm
http://www.acceleratorhighstall.com....ter_torque.htm
The 5AT will torque multiply in gears 1st through 3rd while upshifting and accelerating.
The proper way to upshift the 5AT is to shift with a level or accelerating throttle. This is opposite of what you would do in the 6MT. Don't lift off of the throttle while you are upshifting. You are not helping the transmission to shift and you are actually causing it to shift sloppy or slower because now the tranmission has to correct your error.
The Z's 5AT uses a torque converter. One of the advantages of using a torque converter is it's ability to convert excess velocity into more torque. The Z's TC can almost double the torque input from the engine to the driveshaft. Pro dragsters run 4x to 6x multiplication. A lot of people think that a torque converter loses power but they are actually wrong. A TC actually can create more power on the turbine side (driveshaft) than the impeller side is putting out (engine) as long as the impeller is spinning faster than the turbine. As the impeller and turbine approach similar speeds the TC will begin return the torque for more velocity until it fluid couples. Fluid coupling is not quite as efficient as using a mechanical clutch so the 5AT uses a mechanical lock-up clutch in the 1:1 (4th) and overdrive (5th) gear to achieve the same efficiency as the 6MT. When you shift aggressively and properly in the first three gears it will feel like the transmission didn't engage when in fact it hooked up in less than 200ms. During torque multiplication the impeller will be spinning faster than the turbine and it will feel like it didn't shift until the transmission couples or locks. The RPMs will be up on the engine while torque multiplying. While torque multiplying the stator is returning excess fluid back to the impeller so that it can be re-accelerated back to the turbine until the velocity of the impeller and turbine are almost equal.
http://www.acceleratorhighstall.com....rters_work.htm
http://www.acceleratorhighstall.com....ter_torque.htm
Yeah what he said
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