Drunk argument question

[Bigiggs]

What makes the PE exhaust burble off throttle?

[Deutsche-Broke]

Not having the PE but heard a few, I would say it has to be....

[pj.rodriguez]

Funny. Just had a Newcastle.

[lakylester]

Originally Posted by Deutsche-Broke

Not having the PE but heard a few, I would say it has to be....

+1
For Newcastle.

[pj.rodriguez]

I hear a burble in the stock exhaust also btw.

[CAVU]

Originally Posted by Bigiggs

What makes the PE exhaust burble off throttle?

I believe the burble is coded into the engine software and would otherwise not be a characteristic of the engine. The PPK factory tune adds more burbles, or more pronounced burbles. The PE makes any burbles that exist due to engine software more audible.

Is the creation of artificial burbles sort of a poseur-ish thing for BMW to do? Maybe a little bit. However, it's all about driver enjoyment of the car, just like the replication/amplification of engine/exhaust sounds by the stereo in the M5.

Bottom line: I absolutely love it!!! I can't wait for warm weather to return so I can blast around with the windows down and enjoy the full sound of the PPK2 with the PE!

[MightyMouseTech]

Having done both in stages, the PE does not change it much, just makes it a bit louder. The PPK is what makes the difference. So it is engine tuning that does it, and in fact is listed as a "feature" of the software upgrade.

[Solo_M_Tech]

Mechanically it's caused by valve duration overlap. As you let off the throttle and the engine revs down, alittle exhaust gas gets sucked back into the combustion chamber. This "burble" is the change in exhaust pulse. Performance exhaust makes it louder and cars with valvetronic can be programmed to leave the exhaust cam timing alittle retarded longer. By product of the exhaust cam timing is more top end power.

[Bigiggs]

Originally Posted by SinisterBlack128

Mechanically it's caused by valve duration overlap. As you let off the throttle and the engine revs down, alittle exhaust gas gets sucked back into the combustion chamber. This "burble" is the change in exhaust pulse. Performance exhaust makes it louder and cars with valvetronic can be programmed to leave the exhaust cam timing alittle retarded longer. By product of the exhaust cam timing is more top end power.

Very interesting...thank you sir and thank others for the very insightful and entertaining responses

[Tomas]

Originally Posted by SinisterBlack128

Mechanically it's caused by valve duration overlap. As you let off the throttle and the engine revs down, alittle exhaust gas gets sucked back into the combustion chamber. This "burble" is the change in exhaust pulse. Performance exhaust makes it louder and cars with valvetronic can be programmed to leave the exhaust cam timing alittle retarded longer. By product of the exhaust cam timing is more top end power.

I think it's correct, except that it is the Vanos that change the valve timing, not valvetronic.

[Suhb]

You mean when you accelerate, or let off the throttle?

[Solo_M_Tech]

Originally Posted by Tomas

I think it's correct, except that it is the Vanos that change the valve timing, not valvetronic.

Yeah the vanos is the part that changes the cam timing and " valvetronic" is the program on the ecu, that controls the vanos. And he's talking about deaccelerating.

[Tomas]

Originally Posted by SinisterBlack128

Yeah the vanos is the part that changes the cam timing and " valvetronic" is the program on the ecu, that controls the vanos. And he's talking about deaccelerating.

No. Valvetronic is a system that controls the valve lift. The N54 engine for example does not have it. N55 have.

I thought you just got the two system mixed up?

[Solo_M_Tech]

Originally Posted by Tomas

No. Valvetronic is a system that controls the valve lift. The N54 engine for example does not have it. N55 have.

I thought you just got the two system mixed up?

Thanks for the clarification!

[jsmonet]

It is the reduced amount of sound dampening allowing you to hear the afterfire a bit more clearly.

[ASPEC135i]

Originally Posted by jsmonet

It is the reduced amount of sound dampening allowing you to hear the afterfire a bit more clearly.

[e36addict]

Ahh Newcastle.. I'm thirsty. But what I really wanna know is, what's the internal difference between the regular muffler and the "Performance" muffler? I mean, they're externally identical with the exception of the tips and the plaque.. Anyone know the answers?

[Deutsche-Broke]

Originally Posted by e36addict

Ahh Newcastle.. I'm thirsty. But what I really wanna know is, what's the internal difference between the regular muffler and the "Performance" muffler? I mean, they're externally identical with the exception of the tips and the plaque.. Anyone know the answers?

In my, "uneducated" opinion, I believe that it is the simple concept of resonance.

The same in building a well made speaker. You would never make a speaker yourself by throwing, "any large cone driver" into a general box and plugging it in...

A lot of people do just that, but the results generally suck.

The folks at BMW know every single note that comes out of the motors that they produce at every RPM and load. This would also make it quite easy for them to make a similar sized exhaust chamber that found that, "sweet spot" that makes everyone around here giggle like a school girl.

It's as easy as using a frequency analyzer and finding that "sweet spot" and adjusting Q, giving the important frequencies some boost and, "room to breathe" and working through the power band to continue the intent throughout the exhaust..

I've seen custom exhaust shops do this with minimum effort and have no doubt that the BMW mothership has any problem doing this with their massive resources.

I still say Newcastle..

[Andrewcoja]

It's unspent fuel getting into your exhaust and combusting causing little popping sounds.