Date: Tue, 17 Sep 2002 10:41:23 -0700
Reply-To: warmerwagen@HOTMAIL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Keezer <warmerwagen@HOTMAIL.COM>
Subject: AW: A Vibration Free TIICO Exhaust System - A Successful Work in
Pro
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My guess from personal experience is the location of the engine mounts on the WBX and the Diesel . The WBX and Air-cooled have the mounts above the muffler. The mounts for the Diesel (and Tiico) are farther back from the muffler. So the engine "pivots" so the rear of the I-4 engine has more undampened movement.
Also, the WBX doesn't have as much tendency to spin as the flat four design is self balancing. The I-4 engine exerts a lot of sideways force, this is why such large rubber mounts are used.
The Diesel uses a small and light weight muffler.The Tiico header , cat and muffler all add extra weight. Even still, the rubber mounts always break, and I don't think they are big enough. They used them because the engine vibrations are so strong in a Diesel that the muffler and pipes will shake apart otherwise.
I had my 2.1WBX muffler rigidly mounted on my I-4 engine- I had to go back to the Diesel rectangular mounting, the vibration sounds were very loud. So the rubber mounts ae need between the muffler and the engine unlike the WBX, or else the muffler becomes like a engine vibration amplifier or sound box.
Any better guesses than mine are welcome-
Robert K
1982 Westfalia 2.0 Golf powered
--- Re: A Vibration Free TIICO Exhaust System - A Successful Work in Progress
Ed, any pictures would be helpful. I have always thought that rigidly
mounting the entire exhaust system (like they did in the waterboxer) would
be the way to go. I guess it isn't but I wonder why? Any ideas?
Thanks,
Ken Wilford
John 3:16
http://www.vanagain.com
Phone: (856)-327-4936
Fax: (856)-327-2242
-----Original Message-----
Wrom: TLBXFGGMEPYOQKEDOTWFAOBUZXUWLSZLKBRNVWWCUFPEGAUTFJMVRESKPNKMBIPB
Of Ed McLean
Sent: Monday, September 16, 2002 11:40 PM
To: vanagon@GERRY.VANAGON.COM
Subject: A Vibration Free TIICO Exhaust System - A Successful Work in
Progress
Several in the "headers are headed south (TIICO)" thread have referred
to the "steel mesh section" in the TIICO header. Actually, this is a
steel bellows flexible section that has a braided steel protective outer
layer. This section will flex in a bending mode but it will not twist.
These are available from Exhaust Productions Inc. (
http://www.epiflex.com/ ) or the same item from JC Whitney for about
half price (~$22).
It seem that several people are having serious problems with the exhaust
system on the I-4 conversions. I feel I have made significant progress
in addressing the problems with the TIICO exhaust system and I would
like to share my observations with the list.
Although the TIICO header has a flexible section, this section is
located in the wrong place to do any good in reducing the vibration. As
a result of its location, the flexible section is asked to twist to
adsorb the flex when the muffler moves up and down in the rubber
mountings. The flexible section will not twist at all and the motion is
taken up by bending the exhaust header pipes. This consequently makes a
nice vibration harmonic oscillator using the spring of the header pipe
as the force and the muffler as the mass. The resonant frequency
happens to correspond to the ~3600 to 4200 rpm range of the I-4 engine.
It is this vibration that is breaking the header pipes.
I have built an bolt on exhaust system to address this problem. The
only welding required is the attachment of a 3-bolt flange to the
flexible exhaust section and the total cost is about $80. While it is
not a perfect solution at the moment, I find it totally acceptable in
reducing the vibration and noise of the TIICO exhaust. I think there
still is a little more improvement available so I am not really ready to
recommend this to others. However, if I am not able to do any better, I
will still be totally satisfied with the results. I really don't know
how to describe the reduction in vibration except to say at all engine
speeds the stock speaker grills in the front doors vibrate more from
music than the gearshift lever does from the engine. At 70 mph there is
no vibration from the gearshift lever. One other contributor to the
list has ridden in the bus and I would invite him to share his comments
with the community on the reduction in vibrations.
I assembled the exhaust system using a 5" exhaust clamp and a piece of
1.5" angle iron to solidly mount the catalytic converter to its shock
mounting. This fits neatly around the stock converter and attaches to
the TIICO original bracket, replacing the wasserboxer muffler bracket
that never actually fit the converter. Attached to the converter is a
6" flexible exhaust section followed with a 4"x9" oval muffler 18" long.
The outlet end of the muffler is attached to the right frame rail with
a traditional muffler hanger. The exhaust hanger attached to the oil
pan is removed entirely. This system eliminates the vast majority of
the vibration and noise from the exhaust system by allowing the engine
and the converter to move while the muffler remains essentially
motionless, isolated from the vibration by the 6" flexible section. I
currently have about 2000 miles on the system with zero problems and no
change in vibration or sound.
I still have a little investigation of the system to complete.
Specifically, I find the shock mounting of the converter allows a
little too much motion and, under some temperature and rpm conditions, a
small harmonic oscillation can develop. I plan to modify my original
design to allow the converter to be mounted solidly to the left motor
mount to reduce it's motion. I have the necessary angle iron cut and I
only need time to make the modifications. I also want to investigate
the addition of the updated 1 piece left engine carrier and some less
compliant motor mounts. When I've investigated these options, I'll
provide to all some pictures and diagrams with a parts list and assembly
instructions.
If anyone wishes to correspond by p-mail, I'll be glad to supply a few
pictures and diagrams of the work in progress.
Ed McLeanHolen Sie mehr aus dem Web. Unter http://explorer.msn.de/intl.asp#de gibt es einen KOSTENLOSEN Download von MSN Explorer.
