Date: Mon, 15 Oct 2001 09:25:06 -0400
Reply-To: Gary Stearns <gstearns@OPTONLINE.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Gary Stearns <gstearns@OPTONLINE.NET>
Subject: TiiCo Vibes, Flex joints, etc.
Content-type: multipart/alternative;
Hi Gang-
My efforts toward eliminating inline 4 vibrations of the TiiCo kit became an
obsession; but did produce some results. First, regarding exhaust vibes,
flex joints etc., I see by posts here that some kits had flex joints
installed in the downpipe as delivered, some didn't. Mine did. Though it
had a flex joint, it was very stiff, couldn't possibly dampen vibrations. I
had a race type ball & socket exhaust flex joint (btw:the typical VW
connection w/the iron donut can't be made into a useable flex joint) kicking
around (came from Techtonics, couldn't fnd it in thier online catalog though
http://www.tttuning.com/index.html). I removed the flex joint that came
installed, and found it to be a type I had never seen before. Outside is
the same stainless wire mesh as usual, inside is spiral wound tubing like
electrical BX cable. Every flex joint I've seen is seemless corrugated tube
on the inside like an accordian. No wonder it was so stiff. Anyway, the
ball and socket joint has been successful at interrupting the the
transmission of vibes to the rest of the exhaust. Problem is the joint is
mild steel and will rust and seize sooner or later. I plan to recreate the
entire exhaust in stainless at some point and will use a stainless ball
joint from Wicks http://www.wicksaircraft.com/showPage.phtml?pagenum=241.
Last tip for exhaust; I found that I had not used a "spacer" that TiiCo
provided to move the right side exhaust mount more toward the center of the
Van. I installed it and found another improvement. Something to do with
frequency, vibration period etc.
My last and strangest discovery was Sorbothane. Yup, the stuff in the heel
of your expensive running shoes. When I had posted to the list about trying
stuffing the gaps in the motor mounts with foam, polyurethane etc., one
response came back saying try Sorbothane. Absolutely amazing stuff. Couldn
t find it for sale in raw form, so I bought a Bell bicycle seat gel pad and
cut 'er open. To install it the mounts have to come out. On the bench, I
used a flywheel puller to open the gaps in the mounts. This allowed an
easier install of cut-to-fit pieces, and allowed the mounts to squeeze the
Sorbothane a bit when released. Sorbothane is strange stuff. It could make
very convincing "alien flesh" at halloween. I had some fun grossing out my
kids.
All of the resonant buzzing is now gone. It's still an I-4 back there for
sure, but the sound is consistent throughout the rev range. No more brain
scrambling peak at 4,000 rpm. A side benefit of the Sorbothane: no more
engine continuing to bounce after you hit a bump. The rear end feels much
tighter and more "tied down".
I did do some temperature extreme checks on this stuff. All afternoon in
our freezer didn't change it's consistency at all...ditto a drop into
boiling water. Should be OK year round.
Now our TiiCo install is really fun. I can wail it up to 5,500 rpm without
wincing as I pass through 4k.
Gary
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