Greg D.

Well that's new... I noticed a faint rattle-like noise at exactly 3100 RPM for the first time yesterday, on the way up the range - very gradually (not down)... it's gone by 3200 or with a stronger application of power..
Sounds like a heatshield rattle but who knows... If you rev thru the range you can't notice, it's only noticeable when cruising and going up the range very slowly in a higher gear...
I found a thread on this very thing on 6speed online but not here, surprisingly, unless that is the stumble y'all talk about, but no stumble at all for me - just a buzzing sound... Of course my entire trip after that seemed to be at 3100 rpm after I picked up on that ;-( I'd never noticed this before in almost 2 years of ownership... Manual, 3.4, no PSE... No codes, can't always reproduce it, but when you do even my wife can pick up on it and she's got zero mechanical sympathy...

I'm going to try and ignore this, just wondering if anyone else got it to go away - apparently it's not heatshield or muffler and it won't make it blow up, just harmonics... Wish I wasn't so attuned to little crap noises, I'd be a lot happier overall ;-) My old 911 is so damn loud in comparison that I could never hear something like that over the bleeding in my eardrums !

991carreradriver

Well documented on 991.1 & S. Spend some time researching and you find numerous posts on this variocam issue.

stealthboy

In my humble opinion this is not the well-documented variocam issue. This is a resonance of *something* back there at 3100-ish RPM. I get it too. It's like a heat shield or something just shaking. I know what he means, and I get it on my 991.1.

991carreradriver

It has nothing to do with a heat shield, tests have been performed by members to eliminate it, including by me. I removed the right rear shield, test drove and it was still there on both my 2014 and 2016 C2's.
There are two threads on Rennlist just search vibration and a very extensive threads on 6 speed. This vibration at 3100-3200 is caused by the variocam transition.

GregD

That's good enough for me... Thanks !

Searching was not obvious on 3100 rattle -> nothing... If you don't know it's variocam you get nothing... I knew it wasn't the stumble...

I'm surprised I never noticed it before, honestly... I will file under Porsche idiosyncrasies and try to ignore it henceforth.