What is this sound??? exhaust question

[Roosell]

Originally Posted by tommy986

This is what i want:

http://www.youtube.com/watch?v=1Gk5y_mpOW0

Make that two, please! Very nice.

[jhandy]

looking at the picture of this muffler from the bottom, it is easy to make.
I think that that is the best sounding muffler I have heard yet.

look at the picture. Maybe 100$ in parts.

[Cloudsurfer]

Great for a track car.... I'd be money it drones like mad under 3k however...

[23109VC]

http://www.youtube.com/watch?v=s9poqfZ4m2I&feature=related

here is another youtube video of a different boxster with an aftermarket exhasut, this one is speedart, and if you listen VERY carefully, you hear that EXACT same sound as the engine nears idle as it's decellerateing..

WTF is this sound? my car with a pedro does it, and these two cars do it, both with different exhausts...leading me to believe it's NOT "the exhaust" but rather some sort of sound the motor is making, and it's just audible coming out the exhaust , but it's not a sound that per se was NOT there, and then "there" once the exhasut was added...it's got to be something else making the sound.

is it just a characteristic of some MY boxster motors? my car is a 2000. judging from the fact that these cars on youtube appear to b e"S" models, and have the pre-03 rear bumpers, they are either 00-02 models...... maybe those particualr MY cars had some sound to the motor that was not as audible on later MY 886?

or is there something out of adjustment on the car that is causing it to make this rattling type sound at low rpm....????

here is another one I found....

http://www.youtube.com/watch?v=v7A44uhtu58&feature=related

if you look in the comments to THIS video, someone, 10 months ago, posted "whats the sound, when the rews goes down?like crapy valve sound.."

even some other person noticed it..... so it's not just ME, it's n ot just MY car, and I don't believe it's my exhaust...this is something with the car or the motors..

i'm hoping it's something else on teh car that is worn or in need of replacement that is making that sound.

this is off the wall, but I know my water pump is failing..it leaks when the car shuts off and is cooling and it's gotten progrssively worse over hte past few months.... I have an appt to have it fixed next week... i am doubtful that this is the problem..but wondered if the failing impeller or sometjhing like that could be making a rattling type sound as the revs drop and you just hear it coming from the engine bay area and it sounds like it's the exhaust but it's not?? i know water pumps go bad on a lot of these cars and for all i know, these handful of cars have a similar failing pump?? not all the 986 boxsters with exhausts make this weird sound....

so it must be something besides the exhaust. now maybe it's an inherent characteristic of the motor...but given that it sounds so $hitty... i can''t imagine Porsche would have designed the car to sound lke that.... so my gut tells me that this is something that is "wrong" with the car, or out of adjustment, or worn, that could be fixed. it doesn't sound like something as simple as a loose heat shield or some kind of loose bolt...but who knows....

when the car goes in for hte water pump i'll have my mechanic look at it... and hopefully he can figure out what it is... but since this sound is prevealent on at least a handful of boxsters that are on youtube...i have to imagein someone here has heard this...or can listen to these clips and tell me WTF this sound is...

or is this how it's "supposed" to sound???

[Boxtaboy]

My Dansk exhaust does not exhibit that raspy sound as the revs come back down, but it is also not as loud as a lot of these aftermarket exhausts. I think that noise is a byproduct of having less baffled mufflers, and is a character of the sound the car gives off if you don't have a muffler that is tuned specifically to cancel out that noise.

As you noted, the noise was not present when you had the stock, unmodified muffler on. I think the stock muffler does a great job of canceling out annoying drone and rasp, but as most people find, is too quiet. The factory PSE sounds nice, but also doesn't exhibit that annoying noise as it unwinds, so it's just a matter of finding another set up that gives you exactly what you want.

[BoxsterS21]

It won't harm the motor, it is just the way the fuel changes are.... Also I think it sounds great!

[Roosell]

I don’t know ****************e from Shinola, but that won’t stop me from offering an opinion. I think that sound comes from the throttle body closing the rest of the way. The throttle is electronically (as apposed to mechanically) articulated, no? I’ve noticed that my car has very little engine braking immediately after closing the throttle, but the braking increases if I stay out of the throttle for several seconds, like when coasting to a stop sign. My wild and unsubstantiated guess is that rattle is a harmonic phenomena having to do with the throttle body closing the rest of the way.


Or, it could be the muffler bearings.