Frederic Breitwieser/turbo discussion, design Q's

[Clarence Wood]

  I would like to inject a bit of information here:  The banjo turbine discharge.  "Turbochargers" by H.MacInnes, pg.72-73.  Stating that the banjo-type fitting worked at least as well as a straight exhaust.  I mention this because of the way the turbo spins the exhaust it is important to change the swirl into turbulent flow "as soon as possible".  I have been trying to find a Banjo but have not had any luck.  I think it is really slick the way it works.  
  And, I quote from the text: "A slight restriction in the exhaust pipe can be an effective high-speed boost control.  An exhaust restriction can be used as a fail-safe method to limit manifold pressure without low or medium rpm power penalty."

At 02:22 PM 3/17/99 -0500, you wrote:
>> Turbo engines respond to all the same tuning tricks as atmo engines.  Tuned
>
>yes they do.  The only thing I would append to your comments if I may is that
>with a turbocharged system, you want the exhaust system to have as little
>restriction as possible, because the turbo itself is a big spinning CORK.  You
>want little, if any back pressure pre and post turbo, especially with the larger
>turbos.
>
>> headers included.  Conventional wisdom states that a 4-2-1 header gives
>> better mid range and a 4-1 gives better top end.  There is lots of racing
>> engines that use 4-2-1 designs  With largish tube diameters and appropriate
>
>What would you recommend for low to mid end then?  I am curious, for I'm
>building a 383 Mopar B block stroked to 431 cubes (or more if I can figure it
>out), using the EEC stuff to manage it.
>
>What I ended up with, since the vehicle is a truck and not a race car by any
>means, was either to make shorty exhaust manifolds that go forward, attach the
>turbos there, and blow up into the intake system I'm almost done fabricating.
>
>Also, even with turbos, and H-Pipe offers better performance.  I am clueless as
>to why this is the case, I believe it has to do with exhaust pulse
>reverberation, however the H pipe does make a difference.  Original testing on
>the Buick before we ended up with bizarre headers, the tried the H pipe before
>the turbos, and after the turbos.  Post turbo offered slightly more power and
>less turbo lag from idle.  We used a 3" H pipe.
>
>BTW, I had called up to the shop, and found out that I was completely mistaken.
>The 180 degree headers are in fact 3 to 1 headers, however underneath the dry
>sump oil pan there is an "X" where the left side feeds the right side, and the
>right side feeds the left side, in conjunction with their own side.  My friend
>said conceptually, its the same advantage as an H pipe, however being an "X"
>rather than an "H" the crossover points are somewhat aligned with the airstream
>versus the H pipe which is a 90 degree bend of course.
>
>See, I made this and I didn't even know what it was LOL.  Hope that clarifies
>what we did, and makes sense to some of the discussions.
>
>Hey Bruce, can I borrow your cone shaped hat for standing in the corner for 15
>minutes?
>
>
>--
>
>Frederic Breitwieser
>Bridgeport CT 06606
>
>1993 Supercharged Lincoln Continental
>1989 HWMMV w/turbocharged 500cid Caddy
>1975 Dodge D200 Club Cab soon to have 431 stroker + turbos
>2000 (I hope) Buick GTP (Mid-Engined Sports Car)
>
>
>