Why does a Porsche Macan have a flapper valve in the left tailpipe?
I could see it opening and closing while I was behind the car (?) In slow traffic.
Why does a Porsche Macan have a flapper valve in the left tailpipe?
I could see it opening and closing while I was behind the car (?) In slow traffic.
BMW has done this on a bunch of models as well. It's to direct all of the exhaust out one tip under light engine load, presumably for noise reduction or something like that.
A lot of German cars have this and yes, it's to comply with some German regulations about allowable noise levels.
Some American cars have this too, like many Camaros for example. (I have only seen it on 6.2l models)
Acura had a pressure based system in the early 90s that did the same thing.
In reply to Noddaz :
Now I'm looking...
It's the optional adjustable Sports exhaust. Normal mode is valve closed which uses the regular mufflers, and when you hit the button the flap opens allowing a more straight through exhaust that's louder / sportier. Super common option on Porsches and Audis, though you can't always see the valve. It's like old school cutouts, but with an electronically operated flap.
Pete. (l33t FS) said:Some American cars have this too, like many Camaros for example. (I have only seen it on 6.2l models)
Acura had a pressure based system in the early 90s that did the same thing.
It's why only two of the four exhaust tips on a c7 get dirty. I forget if it's the inner two or the outer two that are normally closed.
It's so you can feel like Sonny and Will with some cool ass exhaust stack flap.
5the generation (00-03) Maximas had that on their stock twin-pipe muffler as well, though the flap usually rusted and was non-functional after a few years from new.
My B9 S4 has it but it and the Macan probably share a ridiculous amount of parts between them.
My c6z has it and they, unsurprisingly, sell a device that allows you to choose open or closed.
open and they are almost straight piped. With cats and the perforations in the pipe it's not obscene at all. And closed they're pretty quiet.
i modified the straight pipe section to be true 3" all the way and eliminated the perforated section but left the muffled section alone so mine is a bit louder (and faster!!) open but still super quiet closed.
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