2005 MCS popping noise

[royevans]

Forgive the newbie question...but what causes this? I love it, just curious!

[beken]

MCS is supercharged. When accelerating, you get boost. The intake air is compressed into the cylinders. When decelerating, you get a bit of vacuum, which causes what seems to be a bit of backfiring. Hence the popping noise.

It's quite normal.

[royevans]

Thanks!!

[Kaelaria]

OMG what body cavity did you pull that answer out of! !

The popping is 100% from the design of the exhaust system and it's backpressure.

[jon vital]

Yeah, especially as it does it at very low revs too.

[Restyle]

...and it never did it on the previous Cooper S`s prior to the 2004 makeover

[Lee Bradshaw]

Quote: Originally Posted by Restyle

...and it never did it on the previous Cooper S`s prior to the 2004 makeover

Mine does.... Maybe the exhaust is blowing!

Not getting it checked though, it sounds lovely.

It is a prefacelift March 04' though???

[laura f]

Quote: Originally Posted by Restyle

...and it never did it on the previous Cooper S`s prior to the 2004 makeover

i thought it was an 05 model year thing I am willing to be wrong on the timing.... but it sounds fantastic

[Lee Bradshaw]

Quote: Originally Posted by villa mini

i thought it was an 05 model year thing I am willing to be wrong on the timing.... but it sounds fantastic

You're welcome to come and have a listen to mine! Everyone round these parts is forced to listen to it anyway!!!!

[kapps]

The earlier models do it, just not nearly as much. You'd have to rev up to 3k rpm (or very close to it) and quickly let off. Anything more or less than 500 rpm off 3k and it won't do it. I took a test drive in an '05 and I could hear it on every shift...even as low as 2k rpm. It sounds sweet. Aftermarket exhausts increase it's presence.

[laura f]

http://www.mini2.com/forum/general-discussion/84809-pop-pop-pop-pop-pop.html

this thread makes me grin

[RenaultF1]

Quote: Originally Posted by Kaelaria

OMG what body cavity did you pull that answer out of! !

The popping is 100% from the design of the exhaust system and it's backpressure.

...what a great response...

[Parc77]

Was going to say both my 2002 S and 2004 S have always made the noise, but I know it happens alot more with the 05 cars since the slight power increase/mild makeover, wonder if the next model will have flames coming from the exhaust

[djbohne]

Quote: Originally Posted by Parc77

Was going to say both my 2002 S and 2004 S have always made the noise, but I know it happens alot more with the 05 cars since the slight power increase/mild makeover, wonder if the next model will have flames coming from the exhaust

I'd trade my 05 in for a 06 in a heartbeat if it ever did that... how friggin cool would that be...haha..

[beken]

Quote: Originally Posted by Kaelaria

OMG what body cavity did you pull that answer out of! !

The popping is 100% from the design of the exhaust system and it's backpressure.

Nice response....and back pressure is cause by ....?

I remember lots of popping sounds from Mazda's RX-7s as well as other turbocharged cars. All engines internal combustion engines have back pressure when decelerating. However, you get a lot more of it in boosted engines. Of course I agree with you that the MINI's probably tuned to exaggerate the noise and I rather like it.

I pulled the information from some cavity where I worked on a thesis on fuel additives for increasing the speed for flame expansion in various forms of fuels.