[Vwdiesel] Muffler or Streight pipe

[Chris Geiser]

I ran a straight pipe out the back for 3-4 years on my 92 Jetta; finally sprung for a muffler when the pipe broke, and I think its actually louder IN the car with the muffler now.  Of course behind the car where the cops listen, its quieter now...


Chris 




-----Original Message-----
From: Tad <tadc at europa.com>
Sent: Wednesday, December 09, 2009 5:15 PM
To: William J Toensing <toensing at wildblue.net>
Cc: vwdiesel at vwfans.com
Subject: Re: [Vwdiesel] Muffler or Streight pipe

I took the muffler off my TDI years ago, and haven't really missed it.
 There is a bit of a 'drone' at certain RPMs that some (on the forums, not
anyone I know personally) find annoying, but I would certainly not call it
loud.  It passes the 'mom test' - my 65 YO mom rides in my car without
complaining about the noise, as well as the 'wife test'.  Although my wife
actually says that she likes the sound, because it 'sounds manly'! :P

Bear in mind though that I kept the stock pipe diameter and routing (up and
over the rear axle beam, which the muffler guy found to be a PITA) which may
help keep down resonant sounds.

I used to have a rally-prepped Audi 4000 with a large-diameter exhaust and
minimal mufflage, and it would regularly set off car alarms and whatnot.
 The TDI is about 10 times quieter than that.

All that being said, there was minimal power or MPG gain from the mod.
 Maybe the turbo spools a little quicker - but with the VNT there can be too
much of a good thing with that.  I had to install a boostvalve to arrest the
big overboost spikes.

On Wed, Dec 9, 2009 at 3:23 PM, William J Toensing <toensing at wildblue.net>wrote:

> Here is something that might make for an interesting discussion. I used to
> own an Argosy (Airstream)motorhome that the previous owner had installed an
> Isuzu 6 cylinder industrial turbodiesel. The engine had no muffler, only a
> straight pipe. I was told that the turbo reduced the noise level enough to
> be legal & with no muffler, would get better MPG. I wished I had kept it as
> at times, it got 17 MPG! This on a 26 foot motorhome on a 1&1/2 ton Chevy
> chassis with a THM 400 Hydromatic plus a Gear Vendors  gear spliter. But my
> wife didn't like the noise.
> Become of my prior experience with the Argosy, I wonder if replacing the
> muffler with a straight pipe on VW & Mercedes turbodiesels would
> significantly improve MPG? Also, does the turbo quiet the engine enough to
> be legal? I suspect someone out there has experimented with this. I also
> know that some engines have tuned exhausts & that decreased or increased
> back pressure could decrease MPG. The Panhard PL-17 was one such car.
> Bill Toensing, Nevada City, CA.
> _______________________________________________
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> Vwdiesel at vwfans.com
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>
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