Date: Sat, 8 Mar 2008 23:39:42 -0800
Reply-To: neil N <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: neil N <musomuso@GMAIL.COM>
Subject: Re: I4 conversion exhaust - some comments
In-Reply-To: <c35.2c33e51e.3504df80@aol.com>
Content-Type: text/plain; charset=ISO-8859-1
Thanks Frank.
I have yet to mount the Jetta engine. It's a 15* mount, though I'm
sure the angle of the engine won't make a huge difference in terms of
choosing between running it forward/back and out the side, or using
the more common approach.
When it's roughed in, I'll have a much better idea of how to run the exhaust.
It'll be mounted soon though. Soon...... :^)
Neil.
On Sat, Mar 8, 2008 at 10:36 PM, Frank Grunthaner <FrankGRUN@aol.com> wrote:
> In a message dated 3/8/08 8:05:41 PM, sfcompost@YAHOO.COM writes:
>
>
> > Neil, with my I4 vanagon I had 2 different exhaust designs with radically
> > different results. The first set up I had built at a exhaust shop using an
> > old Dasher dual outlet manifold, which angles toward the front of the van. I
> > had the shop follow the example I had seen on a German engine conversion site
> > which ran the exhaust forward through the aircooled heater tube hole, forward
> > to a muffler hung under the center of the van, into a 180 degree bend back
> > toward the rear and then out to the driver side ahead of the rear wheel. This
> > required a simple layer of sheet metal as a heat-shield to keep the heat away
> > from the floor, but worked very well and was almost too quiet. No vibration
> > problems whatsoever. My only concern was that the cat was a bit too close to
> > the transaxle. And, I liked having the exhaust coming out of the side of the
> > van, as it told those discerning van-heads that this was no normal
> > air-cooled van.
> >
> Sam and other interested parties,
>
> When I developed the Audi 3A turbo, I used a run to the front-then turn
> around and go back approach. The Audi 80/90 manifolds are definitely the best for
> the I4 gas system. Alistair had to do some clearance nibbling on the 4 to 2
> manifold and I didn't have to on my version. For the Audi turbo, I used the Audi
> 80/90 CA (for California) 4 to 1 version, since it matched the turbo inlet
> well. For the exhaust, I used the Saab turbo flex downpipe (stainless net wrapped
> bellows) then went through the air-cooled heater port and up the drivers side
> to a large bore muffler I studied the VW Golf mufflers with the 90 degree
> offset of inlet and outlet. I liked the idea of coupling two of them together
> to build the 180 degree reversal to run the pipe back out to the rear. In the
> end, I couldn't fit them in place so I went to a large oval muffler (Dynamax I
> think) that had inlet and outlet on the same side. So 2.5 inch pipe in and out
> with the outlet running back to the rear. I used a long and round resonator
> at the exit, passenger side running along the side of the sound-deadening pan.
>
> The muffler and exhaust pipe was supported by universal heavy duty truck
> muffler supports. My space limits were given by the propane tank on one side and
> the auxiliary diesel/fuel tank on the other. I also encountered some floor
> heating and added a heat shield. My target was quiet and this system has certainly
> delivered. I had engineered out vibration previously and no new vibration was
> introduced by this system. No breakage either, but the expansion/contraction
> lever arm (also vibrational and torsional stress) was resolved over a distance
> 5 to 8 times longer than the stock system.
>
> For the TDi, I left this system in place. When I get back to California, I
> try to get some pictures, if there is interest.
>
> For the I4 gas, the Audi 80/90 and Alistairs approach should be fine. I went
> from the Audi 2 port flange to a 2 to 1 collector then to a bellows and out.
> All hanging from the original muffler mounts. Details on Bell's website and
> these comments from faulty memory while feasting on Nürmberger Bratwurst and
> Augustinerbrau.
>
> Frank Grunthaner
>
>
>
> **************
> It's Tax Time! Get tips, forms, and advice on AOL Money &
> Finance.
> (http://money.aol.com/tax?NCID=aolprf00030000000001)
>
--
Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
http://web.mac.com/tubaneil
http://tubaneil.googlepages.com/
|