Date: Fri, 21 Dec 2012 13:59:00 -0800
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: [Diesel-Vanagon] Re: Diesel Vanagon Exhaust Design
In-Reply-To: <CAB2RwfgMYNMK+=q-sTahGskLf3-+=+tNO4KQo=+nzceQtt8LLw@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi Neil,
'usually' ...the catis mounted to the upstream side of the muffler..
and the whole works, cat , muff, and tail pipe go across the back of the
van.
It may be necessary to have the pipe leading to the cat to curve
outboard more..
the 2.1 waterboxer pipe does, compared to the 1.9 system before it ..
the whole cat/muffler is longer ..so the pipe going to it curves more
from outboard.
or you could havea short cat running fore-aft ...then the pipe coming
out of that curves to meet the muffler across the back.
or even a short cat mounted vertically below the manifold..
though that doesn't sound practical.
so why not copy FAS's system ?
true you don't have engine-mounted muffler brackets spaced far apart
like diesel vanagons and oppossed engines do.
So does FAS hang their muffler from the body for that reason ?
I didn't study that picture too hard.
That can be valid ..
like that smallcar system I mentioned...their muffler is really
body-mounted, since it's clamped to the mustache cross bar, and that's
body-mounted.
And they have a robust flex section in the header pipe ..about a foot
forward of the line of cat-muffler.
Nothing wrong with that as long as it works well.
I'd say your essential problem is not having a good widely spaced engine
bracket places.
Re that comment , 'newish territory' ..
as I said, it's not. VW built Bay Buses in Mexico with absolutey upright
inline four engines in the back.
I have seen one in person in Mexico, new at a dealership in Peurto Vallarta.
Those are no longer in production.
So ..go online ....and find diagrams of how VW did inthat vehicle.
I would not be suprised if they transisioned from 'engine-to-body' the
the exhasut ...muffler and cat being body mounted ..or hung from the body ..
though I'm not a big fan of rubber donuts to hand the exhaust from ...
though many manfufacturers do ..even Mercedes.
There is also the common heavy duty rubber/canvas strap from any ole
muffler shop or even FLAPS ..
kinda crude ..but it allows support form above and isolation of vibration.
but see what VW did with that mexican bay bus. I'm sure that's online
somewhere.
If I didn't get some insight there..
I'd probably go with flex section ..
then hang muffler/cat from the body with either rubber donuts or those
rubber/canvas like generic exhaust hangers .
Typically amuffler shop just mounts those to the frame/body with a large
hex head sheet metal screw.
All inline fours without balance shafts have a very buzy period right
around something like 3,800 to 4,100 rpm.
I had a front engine Renualt 16 ( fantastic car ) and some muffler shop
had welded a tab to the back end of the exh pipe..thatscrewed that
directly to the body back there..
no rubber.
It would buzz like hell right at 67 to 71 mph.
yeah ..I think you are in the 'flex section' and 'hang muff/cat from
body with rubber' thing ..
do to nothing convenient, or widely spaced on your engine.
if you find a diagram of the Mexcian Bay Bus exhaust system layout I'd
like to see it.
I don't know the production dates ( ended about 6 yrs ago maybe )
...Those must have started in the 90's I'd think,
quite some while ago.
scott
www.turbovans.com
On 12/21/2012 12:07 AM, neil n wrote:
> Thanks for your thoughts and comments Scott.
>
> Yah I know; don't reinvent the wheel. < grin >
>
> I just don't want to have to do this exhaust "design" and build job a 3rd time.
>
> My engine is mounted at 15º, and I'm running a cat so the space
> between the driver and passenger side "DV" brackets isn't as wide as a
> 50º diesel Vanagon engine. The arm I built off of the driver side
> bracket, Image: http://tinyurl.com/9ythuq5 (uses a 5" muffler
> clamp) was an add on redesign done shortly before the down pipes
> finally cracked. I might keep this cat support design but don't really
> like the idea of running one the driver side exhaust support to the
> cat.
>
> Neil.
>
>
>
> On Thu, Dec 20, 2012 at 10:23 PM, Scott Daniel - Turbovans
> <scottdaniel@turbovans.com> wrote:
>> hi ..
>> as I said, stock DV exhaust systems don't have a problem with cracking.
>>
>> on the two DV systems I have laying around that have a flex junction in them..
>> the muffler is still mounted to the engine with rubber mounts.
>>
>> the stock system is So Good that I have reproduction left and right muffler brackets that I had made.
>> Nice 'n heavy duty too.
>> Have a few sets left.
>>
>>
>> I get them cut out by a computer controlled machine ..
>> very simple to order say 5 more , at any time. - as they aleady exisit in a computer program at my fabricator's.
>
>
>
>
> --
> Neil n
>
> 65 kb image Myford Ready For Assembly http://tinyurl.com/64sx4rp
>
> '88 Slate Blue Westy to be named.
>
> '81 VanaJetta 2.0 "Jaco" http://tubaneil.googlepages.com/
>
> Vanagon VAG Gas I4/VR Swap Google Group:
>
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
>
