Engine rev flutter sound on upshifts

[autogyro]

So you wont talk either. Know how you feel.

The difference is he hasnt looked for attenion by telling us about what he doesn't want to talk about at every available oppertunity.

Hmmm, interesting use of English.

[Giblet]

I'm not 100% sure exactly what you are refering to.

Probably the sound of un-burnt fuel in the exhaust when driver shifts and ignition is cut or retarded for a split second to reduce torque?
Listen to the cars at the track when they use pit-lane limiter, when its activated initially you get a lot of un-burnt fuel before the real limiter kicks in.

Some posts are getting very close to information I don't want to discuss, otherwise I would say some more.

Some very random theories.

I will try to find a video clip of the in car view, over Schumi's head, looking at the airbox.

To be clear, it was at the top of 6th gear, right _before_ the shift. 7th never made the noise, but the engine was probably not winding as high RPM wise. It sounds similar to the popping on downshifts.

I think you could be right about the unburnt fuel in the exhaust. That would explain why it happens at very high revs, where the engine might not be as efficient at burning.

Is that correct, that the engine would have more unburnt fuel pass through at higher RPMs?

[Giblet]

[youtube]http://www.youtube.com/watch?v=XGM2X3MiKrY[/youtube]


This clip I didn't hear the noise before shifting into top gear, but it is in top gear.

Watch from :50 seconds in it is heard a lot.

After listening to it a lot, it might n fact be another trancever thing.

[F1_eng]

It doesn't sound right in my oppinion, but I have never worked for Ferrari so I don't know about their engine strategies.

It's could be an acoustic issue.

I'm afraid I can't give you a definite answer, the quality of the audio trasmission doesn't sound the best.

I sneaked the transmission word in, but in a slightly different context.

[RH1300S]

I hear the flutter a couple of times in top gear too....end of the pit straight just before he brakes, also just before Ascari.

Are we sure it isn't just the rev limiter beginning to cut in?

Apart from that I'm amazed we have all talked so much about something pretty inconsequential - me included

[CMSMJ1]

Listening to that video says to me it is not a car thing at all..

just an electrical transmission/buffering kind of deal - like when a PC locks up and skip skip skips before catching up.


EDIT- what a cool track Monza is..

[Giblet]

Yeah I think I was wrong that it wasn't broadcast related. The new oddball audity where the engine note gave the illusion of pitch change through jumping from transceiver to tranceiver.

This flutter actually is two engine notes alternating very quickly until the new transceiver takes over.

If you listen closely, there is an audible click right before the flutter. As well if you if you watch suzuka 2006 you will notice it happens at the tunnel, where in onboards since the eighties have blinked, same thing.

I guess the click has been digitally replaced with "engine note - KERS ?" green video artifacts.

[autogyro]

Thanks for the video and sound track, brilliant.
I think I know what it is.
It could be the Ferrari Kers maximum speed limiter cutting in.
Would that equate to the sixth gear peak revs approximate speed?
If it is then Ferrari are probably adding Kers power more generally rather than at specific times, which I believe is when McLaren use it.
It is of course, useless going by the BBC Kers battery thing.

[xxChrisxx]

Thanks for the video and sound track, brilliant.
I think I know what it is.
It could be the Ferrari Kers maximum speed limiter cutting in.
Would that equate to the sixth gear peak revs approximate speed?
If it is then Ferrari are probably adding Kers power more generally rather than at specific times, which I believe is when McLaren use it.
It is of course, useless going by the BBC Kers battery thing.

If you are talking about KERS in relation to that video above. Look at the timestamp and the man driving the car .

If you aren't ignore the above.

[autogyro]

Thanks for the video and sound track, brilliant.
I think I know what it is.
It could be the Ferrari Kers maximum speed limiter cutting in.
Would that equate to the sixth gear peak revs approximate speed?
If it is then Ferrari are probably adding Kers power more generally rather than at specific times, which I believe is when McLaren use it.
It is of course, useless going by the BBC Kers battery thing.

If you are talking about KERS in relation to that video above. Look at the timestamp and the man driving the car .

If you aren't ignore the above.

OOOPS I was way out there. That is what it sounds like though.

[Giblet]

No there was another thread where we talked about the "New Improved Digital" transmissoin, and the way the engine sounded like it sped or slowed rapidly was thought to be KERS, but I, and many others researched until what was found was a plausible and likely answer.

Oh an Captain Obvious wants his cape back

[autogyro]

I suppose Ferrari did not have some sort of hidden electrical boost back then?
Interesting thought.

[GeeJay]

I've heard this flutter in sound recorded on a test bench, so I don't think it's tyre deformation.

I could be wrong, but I think the engine 'gearchange' flutter is an artifact of several things that are all dynamically linked. For example;

a) the engine management system control strategy coping (via negative feedback loops which have a time constant) with what is basically a step change in engine revs at full load;

b) torsional responses from the driveline components in response to the step change in torque input.

2c

[alelanza]

I've heard this flutter in sound recorded on a test bench, so I don't think it's tyre deformation.

I could be wrong, but I think the engine 'gearchange' flutter is an artifact of several things that are all dynamically linked. For example;

a) the engine management system control strategy coping (via negative feedback loops which have a time constant) with what is basically a step change in engine revs at full load;

b) torsional responses from the driveline components in response to the step change in torque input.

2c

I had forgotten about this topic, coincidentally i was just rewatching the 05 french gp last week and Brundle did state tyre wall flexing as the source of the noise. It makes sense to me, but then again i've never been to a test bench such as the one yo umention.