15000 miles later

[ChristianAB]

Ever since I got delivery of my 370z two years ago, the upshift from first to second as been problematic. When the car was cold, sometimes second gear would simply not engage, sometimes the rev-matching was off. When the car was warmed up, success rate increased but it was still hard work. I tried holding the gear lever differently, changing at various rpms, and even adjusting my seat position. All of these helped but still, shifting smoothly into second was hard work, and required a lot of brain space to be done right every time. I had reluctantly resigned myself to this state of affair, accepting that it was a quirk of the car and that hopefully, in time, I would get better at very precisely nailing the rpms required for smooth upshifts.

However, today, on my way back from getting my winter tyres installed, I was in a good mood, and blipped the throttle on the upshifts just for the hell of it. To my surprise, this produced the easiest, smoothest, almost creamiest upshifts from 1st to 2nd in a very, very long time. After experimenting with it for a couple of miles, I can confidently declare that I have cracked it! Finally, I know how to perform that upshift perfectly every time: simply give a small blip worth about a thousand rpm, which results in the gear knob going into 2nd almost of its own volition and simultaneously smoothly release the clutch as the gas pedal is gently pressed.

It’s just taken me 15000 miles to figure it out.

Has anyone else experienced something similar? (please note that my Z is slightly tuned - ECU, exhaust, cats - so may not be representative)

[Gareth]

DDC for upshift can help with difficult boxes - no blip.

[Pyrolol]

Were you releasing the accelerator entirely while upshifting before?

[ChristianAB]

Were you releasing the accelerator entirely while upshifting before?

Initially, yes. Then I found out that you could maintain a constant throttle, but if your foot wasn't dead still, the car would lurch, which meant doing extra carefully, then lately I was partially releasing the accelerator (by which I mean release entirely for about 0.1 sec and immediately apply a light pressure back on the pedal) as I pressed the clutch.

None of the above were entirely satisfactory, with the result of needing around 2 seconds minimum to change gear smoothly.

[devonutopia]

Most upshifting I'll blip the throttle in my derv - its more a rev matching thing than a dodgy gearbox thing though, but it does seem to make it a little smoother.

[Strangely Brown]

Do you let the clutch in while you blip the throttle? If not, what does it achieve?

[superplum]

??? Are we still talking about fixed throttle/increasing engine revs “blipping” to achieve a smoother change into a higher gear (?); that seems to fly against the norm. What sort of car/gearbox is being discussed – could it be something with an exceptionally light flywheel?

[ChristianAB]

??? Are we still talking about fixed throttle/increasing engine revs “blipping” to achieve a smoother change into a higher gear (?); that seems to fly against the norm. What sort of car/gearbox is being discussed – could it be something with an exceptionally light flywheel?

The stock flywheel is not super light, as it was made heavier than necessary by Nissan to smooth out some of the transmission vibrations. This is not to say that it is heavy and when the engine is warmed up, the revs rise and fall at a decent pace, but there are plenty of sport cars out there with lighter flywheels. Makes me think, the revs rise very slowly and but fall really quickly when the engine is cold.

To make it slightly clearer: there are two difficult points when I upshift from 1st to 2nd in my Z. The first is physically moving the gear lever from 1st and into 2nd, with the clutch pedal fully pressed. This is what blipping the throttle helps with. Then, once the gear level has moved, the clutch pedal needs to be gradually released, at which point rev-matching would need to be done very precisely to avoid any shock.

Thus, it will go like this: press the clutch, blip the throttle and simultaneously move the gear lever. Then quickly lightly press the throttle as you release the clutch pedal.

[ChristianAB]

Do you let the clutch in while you blip the throttle? If not, what does it achieve?

Not sure if I make sense, but it's as though the throttle blipping is helping the synchromesh to do its job (see my previous post also).

[ChristianAB]

Most upshifting I'll blip the throttle in my derv - its more a rev matching thing than a dodgy gearbox thing though, but it does seem to make it a little smoother.

I knew I could not be alone in this.