fast lane

I have a base 997, and I've noticed a "flat spot" between 4800 - 5000 rpm's when I'm accelerating hard. This is the first 911 I've owned and I'm not sure if this is normal or something that I should be concerned about. Has anyone else noticed this? Btw It's most noticeable between 2nd and 3rd gear. Any feedback would be greatly appreciated!!

holminator

Haven't noticed.

JohnnyBahamas

If you're using less than 93 octane that COULD be the knock sensors detuning the engine as the predetonation begins. If you're using 93, don't mind me....

rss997

not here......

PV

Very good catch. I notice something similar. I was planning to put it on the forum, but didn't came to it, yet.
Sometimes I have the impression that the fly by wire mapping isn't flawless. Picture the situation that I'm accelerating starting around 2000 rpm and around 4500 rp I'm starting to back off. When close to no acceleration anymore, I sometimes feels a last additional little unexpected push, as if the controller to the fuel valve is making a last little move to its final position while my foot was already steady for a second or two. Also during fast acceleration I sometimes have the feeling that the fuel system is changing its mapping behavior, such that you feel a short change in the acceleration curve (indeed around 3000 - 3500 rpm).
I have to say that I can't put my finger on it, whether it is consistent or just imagination, but it happened already more than once.

Gary R.

No, but a couple guys here (me included) noticed that if you accelerate slowly, at around 3600RPM there is a little "burp" for 200 RPM or so. If you are hard on the throttle it doesn't seem to be there..

Or maybe it's around 3200...

CO997

I see the same thing Gary sees however mine is right at 3000 not 3600 liike he says.

Weissy

I have a S and no doubt at 3k rpm there is a burp for about 200 rpm if I am not leaning on it.

tagheuer

I have the c2 as well and I have a very noticeable "burp" at 3k which I only noticed after installing my headers and bypass pipes.

jcm

Around 3 or 3500 the Vario cam is changing....

PV

OK, where can find some info on that?

MMD

Any chance it is the normal flattening of the power output curve? Just guessing.

TT Surgeon

Might that be the variocam?

fast lane

So I guess I'm not the only one. I brought my car in for service today to fix the system fault hood latch problem, and decided not to mention this acceleration concern until I was able to check back and see if anyone else had experienced it. Knowing the service department at my dealership it almost seems like a waste of time to have them check it, the ansewer will be "we didn't notice anything". What are you guy's planning to do about this problem?

Gary R.

I fixed mine. I simply accelerate harder and there is no "burp". It only happens to me during a slow acceleration and even then not all the time...