Hmm.... didn't know that.

Not a bad idea. Keep it all 1 5/8".

Thanks Jake!

On Thu, Mar 27, 2008 at 9:36 PM, Jake de Villiers
<crescentbeachguitar@gmail.com> wrote:
> If it were my van I'd make the whole exhaust out of 1 5/8" tubing. Your runs
> are shorter than the originals and the 2" pipe will only serve to make it
> noisier and to raise the RPM at which max power is developed, neither of
> which will help your German Driving Apartment get down the road 'better'.
> :)
>
>
>
> On Thu, Mar 27, 2008 at 8:58 PM, neil N <musomuso@gmail.com> wrote:
> >
> > I wrote:
> >
> > >  The only real technical stumbling block right now, is that the
> > >  collector will be shorter than the stock Jetta.
> >
> > Oops.
> >
> > meant to say "length of pipes to collector will be shorter than the stock
> Jetta"
> >
> > Neil.
> >
> >
> >
> >
> >
> > On Thu, Mar 27, 2008 at 8:50 PM, neil N <musomuso@gmail.com> wrote:
> > > Thanks for the info Kim. I suspected it would be a poor idea to reduce
> > >  the ID of the Jetta pipe down to a Vanagon cat/muffler.
> > >
> > >  I will stick with a 2" ID on pipes after collector. The collector
> > >  itself (Jetta) has 1 5/8" pipes.
> > >
> > >  The only real technical stumbling block right now, is that the
> > >  collector will be shorter than the stock Jetta. The overall length of
> > >  the system will likely be shorter than the stock Jetta, so that
> > >  technical aspect I have to ignore.
> > >
> > >  At this point, I'm flying blind in a way. I'm sure I could weld the
> > >  parts together, but collector length, well I'm learning. Next thing to
> > >  find are some 90 mandrel bent elbows. I was able to save the flange
> > >  from the Jetta down pipe, so I'll weld the 90's to that then to the
> > >  collector, and so on.
> > >
> > >  Maybe Mr. Google will yield some info on collector lengths etc.
> > >
> > >  Neil.
> > >
> > >
> > >
> > >
> > >
> > >  On Thu, Mar 27, 2008 at 8:16 PM, Kim Springer <kimspringer@rcn.com>
> wrote:
> > >  > Neil,
> > >  >
> > >  >  Pay attention to the stock system and consider using the same
> diameters and
> > >  >  lengths of pipe.
> > >  >
> > >  >  Exhaust systems are designed for length to the collector, from the
> collector
> > >  >  to the end of the exhaust pipe and the diameters of each of these
> pipes. For
> > >  >  that matter, the length of the intake is designed to tune the engine
> as
> > >  >  well.
> > >  >
> > >  >  I have book on tuning 4 stroke engines and another on engine design.
> The
> > >  >  second is extreemly engineering technical, the first has pretty
> basic
> > >  >  formulas for designing an exhaust system based on displacement,
> valve size,
> > >  >  etc. If anyone is interested, I'll dig it up. In my aircooled days,
> I used
> > >  >  the books to compare off the shelf exhaust system and to choose
> velocity
> > >  >  stacks for my Weber carbs.
> > >  >
> > >  >  Maybe, for a stock engine, this is overkill, but if you are going to
> go
> > >  >  through the process of building a custom system, you might as well
> enhance
> > >  >  the system or build like stock.
> > >  >
> > >  >  Kim
> > >  >
> > >  >
> > >  >
> > >  >
> > >  >  ----- Original Message -----
> > >  >  From: "neil N" <musomuso@GMAIL.COM>
> > >  >  To: <vanagon@GERRY.VANAGON.COM>
> > >  >  Sent: Thursday, March 27, 2008 8:01 AM
> > >  >  Subject: Vanagon exhaust diameter? + Custom exhaust fabrication
> questions.
> > >  >
> > >  >
> > >  >  > Hi all.
> > >  >  >
> > >  >  > I'm gathering parts to fab up the exhaust for my Jetta conversion.
> My
> > >  >  plan:
> > >  >  >
> > >  >  > Short run of 1 5/8" 90 degree pipes from manifold to collector,
> then a
> > >  >  > "J" pipe forward, around, and back to stock Vanagon cat and
> muffler.
> > >  >  > OR an aftermarket cat and muffler with 2" inlets/outlets.
> > >  >  >
> > >  >  > After the collector, the Jetta is 2" pipe.
> > >  >  >
> > >  >  > What is the diameter of exhaust pipe on the Vanagon?
> > >  >  >
> > >  >  > Can anyone direct me to a quiet good sounding, good fitting after
> > >  >  > market muffler?
> > >  >  >
> > >  >  > And how "tight" a bend can be made (mandrel bent) on 2" aluminized
> steel?
> > >  >  >
> > >  >  >
> > >  >  >
> > >  >  > Thanks!
> > >  >  >
> > >  >  > Neil.
> > >  >  >
> > >  >  >
> > >  >  >
> > >  >  > --
> > >  >  > Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
> > >  >  >
> > >  >  > http://web.mac.com/tubaneil
> > >  >  > http://tubaneil.googlepages.com/
> > >  >  >
> > >  >
> > >
> > >
> > >
> > >  --
> > >
> > >
> > > Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
> > >
> > >  http://web.mac.com/tubaneil
> > >  http://tubaneil.googlepages.com/
> > >
> >
> >
> >
> > --
> > Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
> >
> > http://web.mac.com/tubaneil
> > http://tubaneil.googlepages.com/
> >
>
>
>
> --
> Jake
> 1984 Vanagon GL
> 1986 Westy Weekender "Dixie"
> Crescent Beach, BC
> www.crescentbeachguitar.com
>  http://subyjake.googlepages.com/mydixiedarlin%27

--
Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"

http://web.mac.com/tubaneil
http://tubaneil.googlepages.com/