RPM jump when upshifting
 

Hello guys,

I picked up a 2009 370z touring with Sport Package 6MT 2 weeks ago and am loving it. I came from a G37 sedan with the buggy 7AT so it has been a huge change. I am still pretty new to driving a manual so please bear with me.

Like the title says, when I try to upshift from 3-4, 4-5 or 5-6, when I engage the clutch and about the shift, I notice the engine RPM jumps up about 500-1000 rpm. So it goes like clutch in - shift 3 to neutral position - RPM jump - neutral position to 4 - clutch out - gas. Is this normal? Or am I doing anything wrong?

Thanks a bunch. Great forum by the way.

Sometimes the ECU will rev the engine a bit for emissions control but a 1000 rpm jump when up shifting sounds weird. You're off the gas pedal when shifting right?

Maybe not 1000rpm, more like 500rpm. But yeah I am off the gas pedal when shifting.

It doesn't do it all the time thought. It happens less when I shift faster. So should I shift faster? Or should I go to neutral, then wait a tiny bit, then shift to 4?

It's synchro rev kicking in. It thinks you're about to downshift. Shift faster.

That happens to me when the car hasn't warmed up.

Yeah, that happens to me on 4-5 shift only and it is becuase it thinks I am going down to 3 so the syncro rev match is kicking in. It does not happen a lot but does happen. I think it might have to do with how close you are to the gate of the downshift gear.

im pretty sure thats the normal thing for syncro rev match to do guys cause it work on upshifts too not just downshifts. mine does this same thing also when i go to upshift, completely normal when you have syncro rev match on.

I have had this happen will shifting from 4th to 5th and it is just the rev match. I guess the ECU thinks I'm trying to go to 3rd....

this happens to me sometimes. in my experience its because im very, ever so slightly touching the gas as im clutching in.

try this, completely let off the gas a second before you even engage the clutch and then shift up. i doubt you'll get the RPM uprev. the gas pedal is pretty touchy on our cars

Ok thanks a lot guys. Such a great forum :)

I'll try to let off the gas a sec before engaging the clutch and see if the rpm jumps.

Happens on 5-6 sometimes

I am very pleased with the Rev match... EXCEPT... i put the car into neutral a lot while driving (dont ask)... and every time i go to neutral i get a throttle blip.

I don't apply presure to the stick so it doens't know what gear i want, simply move to N and it blips. Stupid thing. :shakes head:

I have to ask -- why do you go into neutral so often?

Coasting in neutral isn't the safest thing you can do.

push the stick towards 5/6 to avoid the blip

If you're getting an SRM throttle blip on a 4-5 UP shift, you're being very sloppy. SRM blips under two circumstances: 1) moving horizontally across a gate in the neutral position between 5-6, 3-4 and 1-2 in a leftward direction or 2) moving 'up' into a gear within the same vertical gate (6->5, 4->3, or 2->1).

If you're in 6th with SRM on and just shift to neutral (between 3-4) you'll get a blip for 4th gear rpm. If you then push 'up' into 3rd, you'll get a second blip for 3rd gear rpm.

Shifting up the gears (1->2->3->4->5->6) should never give blips if done properly and cleanly. However, SRM will hold a proper lower RPM for an upshift if you shift very slowly. This RPM will be lower than what you had for the lower gear though so it's not a blip.

If your car is increasing RPM during an upshift (eg 4->5), you're either being sloppy with your shifting motion or your SRM is f'd up.

When i'm coming to a stop or know i have "exceeded" the posted limit, i like to coast back down to the limit.

Or also, when i'm bored... I kinda drive stick like the car is a skateboard...

kick... push... then coast....

Just trying to mix it up a lil bit on the daily commute.

:iagree:

Very good explanation of what is going on. For anyone getting a throttle blip on up shifts, just practive making smoother shifts and it should go away.

Thank you so much for all the inputs guys! Practice makes perfect.

i notice i get the blips too even when warmed up and am quickshifting from gear to gear. It happens all the way up to 6th, its just the ecu deceleration speed that nissan has it set to. I wonder if anyone out there who has had the ecu re flashed or uprev'd has had the deceleration rate modified? Anyone please chime in if you have had it changed and the responsiveness?

its been stated before that coasting is bad for the transmission.

?????????????

Could you point me in this direction please?

http://www.the370z.com/engine-drivet...-downhill.html

http://www.the370z.com/nissan-370z-g...abits-m-t.html


theres others but you can search the topic on google and so forth. ;) a quick google search brings up TONS of car forums debating the same issue.

someone in here said they had a nissan master tech ride in their car to diagnose a problem. the tech noticed the guy coasted up to stop signs and lights. he advised the Z owner that it was bad for the transmission and to just leave it in gear. whats the technical reason, i duno..

Hey guys,

I am the OP and have another question: with SRM on, when I upshift not from stop but from 1-2, 2-3, etc., is it ok to let the clutch out immediately after shifting? Or should I gently clutch out?

Thanks.

if you drop it out it is considered "dumping" I find that when i glide it and not "dump" it my shifts and actual acceleration is better. You'll know you didn't dump it when you don't get a engine shudder

ewww roy keep the forum clean...

lol always!

OP, I had the same observation/question a few years ago when this forum was pretty new... I thought, no way could this be my sloppy driving, but it was... work on the timing of how you come off the throttle vs clutch in timing... the engagement point of this clutch is different than other cars IMO and if you are coming off another manual it takes some getting used to... and btw, you can adjust the engagement point of the clutch if you continue to have problems (ie put it closer to the floor)

Thank you for the advice. I am still working on my timing and this is my first manual anyway.

Do you know if it's ok to "dump" the clutch when up-shifting from 2-3, 3-4, and so on with SynchroRev Match ON on this car? Will that damage anything?

@Roy: I don't feel any engine shudder when I clutch out. So basically, what I do is essentially clutch in - upshift - clutch out - gas. I don't have to rev match because the SRM does that for me. Is this bad?

srm doesn't match up shifting, i don't know why people are thinking that it does. If you aren't getting a shudder from the motor ( sounds like a f1 car going through the gears) then you are doing a good job also.

it doesn't match on upshifts but it does hold the revs from dropping too low if you're slow to shift

Incorrect. Simply get in the car, turn on SRM, start driving and rev to 4k, shift from 1 to 2 and don't release the clutch. You will notice the RPM's do NOT drop back to idle. They hold considerably higher somewhere near 3k.

That is rev matching.

Now do the same thing except with SRM off. Notice how the RPM's drop back to idle.

That is NOT rev matching.

Also called rev matching....





Rev matching has nothing to do with downshifting or upshifting, but is simply about matching the engine rotation with the rest of the drivetrain. It just does not happen as much on the upshift because if done properly, you can basically "catch" the engine as it slows down. Done properly will allow for a smooth shift, done less than properly will provide a rougher shift.

[QUOTE=Spikuh;1619759]Incorrect. Simply get in the car, turn on SRM, start driving and rev to 4k, shift from 1 to 2 and don't release the clutch. You will notice the RPM's do NOT drop back to idle. They hold considerably higher somewhere near 3k.

That is rev matching.

most of the people on this forum would agree that what you have just stated is incredibly false. When you drive do you hold the clutch down and wait for the speed to match the gearing in your car for the correct shift? I didn't think so. It doesn't work with up shifting. If you read the owners manual and understand that the purpose of srm is for the lazy way of "heel to toe" the brake and gas when downshifting and matching rev's with gears while DOWNSHIFTING, not upshifting.

For the bolded part. It is a very oversimplified example, which I probably should have stated. Of course there is more going on with an upshift, but unless you want to wear out your clutch super fast, letting the RPM's drop some between upshifts is a good idea.

For the rest of what you said, I am going to have to back up to your first quote and restart there.

You said:

The part where you say SRM does not match upshift is categorically wrong. It says so in the manual:

http://i142.photobucket.com/albums/r...m/40edd030.jpg

SRM does not think, "Is he downshifting or upshifting?" It thinks, "Is he shifting?". Look at it this way. If you are upshifting from 1st to 2nd going from 4k RPM's to 3k RPM's, then SRM is going to hold the throttle at 3k RPM's while the clutch remains engaged. Similarly, if you are downshifting from 3rd into 2nd from 2k RPM's to 3k RPM's, SRM is once again going to hold the revs at 3k RPM's while the clutch is engaged.

Her is a youtube video of it in action on both upshift and downshift. Start at the 50 second mark if you want to skip his little intro. No idea who this, I just did a quick search.



So TLDR:

-I should have given a more thorough example.
-SynchroRev Match does work on upshifts.

As for whether or not SRM is the lazy man's heel-toe? This is irrelevant to the point you made in your first quote and is therfore...still irrelevant. As to the purpose of SRM, that is also irrelevant to the point you made as we are talking about how and not purpose.

So can you someone answer the question I've been trying to get an answer:

With SRM on, when I upshift not from stop but from 1-2, 2-3, 3-4 etc., is it ok to let the clutch out immediately after shifting? Does that damage anything?

I've been doing that and have not seen/heard anything weird. And yes, I read the manual which says the SRM helps upshifts as well.

Looks like some people have either gotten used to SRM or drive with it off. I guess I was dumb for reading the booklets that came with the car, lol. I normally turn SRM off for normal driving and turn it on when I want to be spirited (not always though).

OP......you will get used to it. She can be kinda finicky sometimes!

no it does not, he doesn't know how srm really works. You are fine, srm will hold the revs when upshifting but you have to wait a couple of sec to shift into another gear. It is somewhat normal to get blips on a quicker upshift because the ecu doesn't now know what it is that you are planning to do when you are on and off the throttle. IN conclusion change your timing with your foot work on clutch and throttle and you should notice the changes in shifting.

New370Z 3.SynchroRev Match - YouTube


like i stated before spikuh, it is a "lazy" way of heel to toe. here is the demo video that supports my statement before. Enjoy!

Trollololo. Glad to see you agree with me now. :happydance:

Like I said before, you are making an irrelevant point, which I am not saying is wrong, just that it has nothing to do with anything... Go read what you first wrote...

Do you have any idea what you are saying at this point or are you just digging in? :confused:

So long as you are not beating on the car, I doubt you are doing any amount of meaningful damage. For normal daily driving, I find I can let the clutch out in a fairly normal manner immediately after the I change gears. However, I do not force a gear change and I do not dump the clutch, it is all very controlled and "effortless" for lack of a better word. I will try to describe it a bit better.

Whenever I am instructing someone new to a manual car, I tell them that they should be able to shift the car with either the palm of their hand gently resting on the shift knob or with two fingers. That gets them familiar with how the transmission likes to work and the speed at which it likes to shift.

For clutch control, the whole idea is smoothness so I start out telling them to get a feel for the engagement point and work on learning that point. It will be rough starting out as the motion gets commited to muscle memory, but after a couple days it should get pretty second nature. From there it is just a matter of refining the process and learning what to do and not to do with the clutch.

So long as you can make the whole process smooth, wear and tear should be fairly minimal, but ultimately it boils down to practice and learning the car.