[Vwdiesel] Caddy Exhaust

[Tad]

Hey Bill - I did a "mufflerectomy" on my 01 Golf TDI not long after I bought
it new.  I had a shop press-bend a new pipe from just in front of the rear
"axle", up and over (following stock routing), terminating just behind/below
the rear bumper cover with a 45 degree downward bend, barely visible from
behind.

Obviously it must have increased the sound level somewhat, but not so you'd
really notice.  Between the turbo and the cat, not much makes it out.  There
is a slightly noticeable "drone" sound at certain RPMs, and other people
(with other muffler-free TDIs) have complained about that sound being
irritating... but I suspect theirs is worse due to the way they chose to
route the pipe - straight back rather than the up-and-over-the-axle
configuration.  there's also been some discussion of noise varying depending
on where the pipe terminates.

If the older TDs don't have a cat, I assume the noise would be a bit
louder... but as Doyt said, the OEM muffler was a massive 40-lb boat-anchor.

As for performance/MPG improvements... I wasn't keeping meticulous records
at the time, but I'd say "not really".  Probably quicker turbo spool, but
with the VNT it's easy too get too much of a good thing in that department
(see: boost overshoot).


On Wed, Aug 3, 2011 at 4:36 AM, William J Toensing <toensing at wildblue.net>wrote:

> I think I raised this question before but I don't recall all the answers.
> Has anyone tried putting a straight pipe on a VW turbodiesel & if so, what
> were the results? Any MPG improvement? Was it to noisy? I have heard that a
> turbo quiets the exhaust enough to make it legal. I had an Argosy Airstream
> motorhome powered by an Isuzu 6 cylinder turbodiesel. It had a Chevy
> motorhome chassis, Turbohydromatic 400 transmission, also a Gear Vendors 2
> speed over/under drive. The prior owner had installed a straight pipe. With
> that 26 foot Argosy I got as high as 17 MPG!  Wish I still had it. My
> Mercedes 300SD is only averaging around 25 MPG. Around 17 years ago I had a
> Peugeot 604 turbodiesel with an automatic which was a real underpowered slug
> but otherwise was a nice luxury car. Its top speed was around 60 MPH & only
> got around 20 MPG. I never tried it but have wondered whether a partially
> plugged muffler could have caused the poor performance? I had a Peugeot 505
> TD with automatic, s
>  ame engine which would top out around 80 MPH & averaged around 23 MPG in
> LA traffic, as I recall.
> If you go the straight pipe route you could use a copper straight pipe from
> a hardware store if you don't have to do any bending. Should last forever.
>
> Bill Toensing, Nevada City, CA
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