Date: Thu, 20 Mar 2003 22:15:34 -0800
Reply-To: Alistair Bell <albell@UVIC.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Alistair Bell <albell@UVIC.CA>
Subject: new exhaust system (I4) - prelim report
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Finally got the revised exhaust system in my '82 Westy finished.
*background, diesel motor replaced with 1800 8v back in '94, retained stock
diesel exh... due to cheapness on my part. Finally, last summer, the stock
muffler (which I suspect as being the original!) "wore out" ie no more inner
baffles..
I parked the van during the winter and slowly tinkered with a new exhaust
set-up.
I made a muffler "hanger" from 2 1/2" aluminium angle bolted to the stock
muffler mount locations, and 2, 1" box section aluminium tubes that run from
one Al angle to the other. The tubes are spaced about (can be adjusted) 4"
apart, one above the other . The muffler is held to the box section tubes by
SS T-bolt hose clamps.
I made the hanger assembly such that I could strap up pretty well any
cylindrical muffler.
(will take pics sometime)
The muffler is a used (found it at a junkyard and the price was right) Volvo
245Turbo muffler (only a single muffler on that particular Volvo, mind you
the exhaust has to go through a turbo then back to the very rear via 2 1/2"
dia.. tubing) which is about 6 1/2" diameter and 23" long. Has a long input
tube with a '90 that ends up pointing forward in the right direction.
The "new" manifold is from an Audi 80 (4 into 2) and I modified the driver's
side engine carrier to fit.
(see: http://www.members.shaw.ca/bilbo/mount%26man.html)
I also used a section of Audi 2 into 1 exhaust pipe.
I took the van to a local service station that had a good reputation for
pipe bending, (Claire Downey Service), and Jay bent 2 pipes to bring the
exhaust around 180 degrees to fit the "Y" which then fitted into the Volvo
muffler input tube.
The curves were very well made (tight radius) and look much like the Tiico
set-up but bent more in a single arc rather than the 2 arcs of the Tiico.
I was going to put some kind of flex joint in the system, but didn't :),
just a slip joint to connect to the muffler input tube.
The upshot of all this is that the van is *much* quieter now (doh! the old
muffler was really shot), and, wait for it, there are absolutely no
resonances. Mind you I haven't driven the van more than 5 miles, but the
resonance that was there at 3500 rpm and was getting very annoying due to
the bad muffler is gone.
Interior noise is much lower than before, wind noise now predominant, more
transmission noise noticeable in 1st gear. Outside noise? Certainly not a
Lexus, but quieter too.
What I can hear is a bit of what sounds like sheet metal noise, or a belt
rubbing, bit of a "chirp". I wonder if there is a baffle loose in the
muffler or maybe my cam belt is rubbing on the plastic cover. Can only hear
it when standing at the back revving the engine by hand.
The combination of the new manifold, muffler, and injectors bench cleaned
makes the van seem much nicer. Idle is much smoother and I think I have a
little more power.
I need to accurately time (ignition) the beast and to play around again with
valve timing - I replaced adj. cam sprocket with stock sprocket when I
replaced cam belt and got two of marks on the intermediate shaft sprocket
confused and had to "retrace my steps".
Oh, one more thing. I did a compression test on the engine and I got a low
(#2 cyl) of 195# and a high (#1 cyl) of 225#. The figures seem amazingly
good for an engine that has been pushing a brick around for close to 9 years
and 110k miles - and pushing said brick via the low geared diesel
transmission.
"wear indices"? ha!
Alistair
--
'82 Westy -> diesel converted to gas in '94
albell@uvic.ca
http://members.shaw.ca/albell
