SA_992SMT

I recently purchased a CPO 2021 C2S MT a few months back and am slowly getting acclimated to its “quirks and features”. On few occasions, I noticed that when in sport mode and slowly upshifting from 1st to 2nd or 2nd to 3rd, there seems to make an auto blip/rev match like sound. It’s not as dramatic as when downshifting. It doesn’t happen all the time nor does it happen in Normal mode. I notice more in the morning when the car is cold, but recently noticed it when the car was fully warmed up as well. Just to reiterate, it only happens when upshifting slowly.

For those that have a manual, have you noticed this? Is it normal?

Thanks in advance!

aggie57

Can't say it's something I've particularly noticed unless I take my foot off the clutch in the middle of the shift. Then it does do this, for sure.

rk-d

If you're upshifting slowly, its probably rev-matching the upshift since you're allowing the revs to drop to much between shifts.

woobiee

This happens to me if I'm shifting lazily or imprecisely, giving too much time midshift. It feels like autoblip happens around the gate area right before you slot into gear.

SA_992SMT

Exactly how I would describe it. Glad to see it's not an anomly.

BillyX

I notice the same thing on rare occasions from 1st to 2nd in Normal, but only before engine warm up. It has not happened in any of the rev-matching modes.

rouxeny

Mine does this. I have not known why, appreciate the explanation.

dmbryson

My guess is that it is intentional rev hang initiated by the ECU under certain operating conditions. Helps to reduce NOx emissions that occur when suddenly running lean from throttle lift during gear change.

CanAutM3

Rev matching has a rather simple logic, it opens the throttle to match the engine revs to the road speed of the gear being engaged. This is always active be it on upshift or on downshift. On a normal upshift, the revs have to drop anyhow, so no throttling up is needed. However, on a very slow upshift, where the revs are allowed to drop beyond the next selected gear, rev matching comes in action.

You can do an experiment to test this, coasting with the clutch in, move the shift lever from gear slot to gear slot, you’ll notice the engine revs being adjusted for each selected gear.

SA_992SMT

Thank you all to those who chimed in. The various explanations make sense. This is the first manual I've owned with auto rev matching, so I just wanted to make sure what I am experiencing is normal.

woobiee

To revisit this, there is another 'phenomenon' that could be what you are experiencing outside of the auto-blip feature. I noticed if again, I upshift slow, sluggish, and lazily, sometimes my foot releases the throttle just a touch too late. This causes the revs to stay put (or increases slightly) during an upshift. Happened to me just earlier tonight. It could be because in Sport mode, the throttle input is more sensitive than the other modes.