Date: Fri, 28 Sep 2001 13:26:51 EDT
Reply-To: WarmerWagen@AOL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Keezer <WarmerWagen@AOL.COM>
Subject: Re: On exhaust cracking,vibration and noise(not short)for
converted vgons
Content-Type: multipart/alternative;
Frank,
Forget that trip to the Moon-wer'e going to Mars!!
I have been experimenting myself with exhaust configurations however without
the advantage of a state of the art laboratory!
I have arrived at similar conclusions with regard to muffler, pipe,
suspension and length. Here is a chronology:
1995-first muffler:
The vehicle, a 1982 Vanagon Westfalia diesel converted to gasoline 91 Jetta
engine. The exhaust manifold, Diesel-the muffler-Diesel.
The results-loud, and the expensive muffler mounts broke. It was decided that
the pipe diameter was to small for the larger displacement gas engine. Before
changing the exhaust manifold to the 88-92 Jetta one, I replaced the muffler
with a high volume and loud flowmaster, and 2 1/2 "downpipe.
The results: the muffler got so hot it melted a hole in the Diesel oil filler
pipe, stranding me on the freeway. At the time I didn't realize that the
engine was experiencing a false air or unmeasured air condition.had to be
towed home, (three days later I discovered the melted hole that prevent the
engine from starting)
Replacing the tube and improving the heat shielding for the tube and the
engine ran again.
The second arrangement was to use a 88-92 G-J exhaust manifold and a smaller
2" downpipe was settled for. I got rid of the flowmaster and replaced it with
a cheap 20 dollar muffler. The results? noise is inexpensive!
I got rid of that muffler, and added a cat, and used a Walker oval muffler.
It was quieter, but not between 55-65 mph. Over 70 mph, it became quieter.
resonance was worst right where average speeds were driven. So then I tried
using two mufflers end to end-it quieted down, still, there was not enough
length of pipe to cool the exhaust gases.
I am now ready to finish the system-it's take 5 years. In the I-4 scratch
conversion, the Tiico, and others, the muffler gets the least attention.
the Tiico gives you short pipe and a muffler-and it is loud.
What I have now is real funny, but it shoed me something-long pipe is good.
I have a custom made Jetta or Golf dual down pipe-it starts at the exhaust
manifold as two pipes the collect four feet down into one. This is routed
directly under my oil pan diagonally to the right rear where it makes a bend
to the left a goes into a stock 2.1 vanagon muffler in the stock location.
Since there is only one muffler and no cat, it is not as quiet as with the
two mufflers-but the resonance is gone. There was a power and mpg increase,
and it sounds a little racy. I know a shop in a county who will finish my
system like you have described.
I will use the 1993 G-J manifold with dual down pipes that are run rearward
about three feet. Will connect with a muffler that has inlet/outlet on the
same end, and then return back on the right side to the rear and into the
second muffler in the stock location. Six feet of pipe, dual downpipes too
cool the exhaust, and two mufflers to scrub the noise. All without
sacrificing flow, but increasing the backpressure some and helping to retain
low end torque are the other benefits.
Now to deal with sound deadening the body from road noise.
Robert K 1982 Westfalia 2.0 Golf lll powered
Seattle
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