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Crackle & Pop

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
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ronk
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Crackle & Pop

Post by ronk » Tue May 23, 2017 8:26 pm

Why does the 35is crackle and pop?
it won't do incognito fast will it?
You don't stop playing when you get old - You get old when you stop playing!
So I bought a 35is with all the toys to play with. :thumbsup:

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sunnydays
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Crackle & Pop

Post by sunnydays » Tue May 23, 2017 9:14 pm

ronk wrote: Tue May 23, 2017 8:26 pm Why does the 35is crackle and pop?
it won't do incognito fast will it?
They took the guys that made "Rice Crispies" from the Kellogs team and said to them they want the "Snap, Crackle and Pop" sound for the exhaust,

Lol on a serious note i dont know but it sounds fantastic!

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Crackle & Pop

Post by Maniac » Tue May 23, 2017 9:21 pm

35i/iS are programmed to make the noise. You'll note more noise in sport than comfort mode due to such programming.

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ronk
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Crackle & Pop

Post by ronk » Tue May 23, 2017 10:03 pm

I suspect that it must bleed air or air and fuel into the system ?
You don't stop playing when you get old - You get old when you stop playing!
So I bought a 35is with all the toys to play with. :thumbsup:

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Nictrix
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Crackle & Pop

Post by Nictrix » Wed May 24, 2017 8:37 am

On some motorbikes there is a device that lets air into the exhaust system to help cut down on emissions. This also creates popping and crackling on the way down the revs as a by-product.
It used to be on mine but I removed it when I had the bike tuned as it can mess up the fuelling readings and also adds unwanted weight.
E89 2014 35i M Sport Black with Black leather :)

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Crackle & Pop

Post by lordgrover » Wed May 24, 2017 2:53 pm

Heavy air?

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buzyg
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Crackle & Pop

Post by buzyg » Wed May 24, 2017 3:46 pm

For the same reason the ///M does. It has a wicked streak. :evil:
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Crackle & Pop

Post by R.E92 » Wed May 24, 2017 3:50 pm

The air that gets pumped into the exhaust is secondary air injection.

Our cars keep injecting fuel on overrun, this combined with ignition retardation during shifts is what causes the pops and bangs.
Most others cars cut fuel injection during overrun.

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Crackle & Pop

Post by ronk » Wed May 24, 2017 6:43 pm

Apart from being theatrical, does it have any benefit? Does it help keep the turbo vanes spinning for instance?
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So I bought a 35is with all the toys to play with. :thumbsup:

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Crackle & Pop

Post by R.E92 » Thu May 25, 2017 8:48 am

ronk wrote: Wed May 24, 2017 6:43 pm Apart from being theatrical, does it have any benefit? Does it help keep the turbo vanes spinning for instance?
I don't think it has any anti-lag effects. The only benefit I have heard is that it provides cylinder cooling as the fuel is still washing through. That's the purpose of injecting fuel in over-run in race car applications.

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