Intake manifold construction, intercoolers

[Bruce]

Speaking from experience or from theory?.
While you can ignore other issues, when you're discussing an individual
item, when you do put it into practice thou, what happens?.   There is alot
more going on, when you crack the gas then the intake valve looking at the
manifold.
   Your multi butterfly set up *might* have better transistional stuff.
But,  if you  compromise it's plenum area then you'll fall down *big time*
on WOT.

Then we get into air calculations.
  If we're using any plenums, then we're going to have a *choke point*
somewhere anyway.  For either a MAF or MAP system.  the MAP spikes are so
serious that you need averaging of them to make a worth while signal out of
them anyway.  The MAF is self explainatory.
  Then comes into issue are the matters of AE.  With a longer column of air
the lesser the need for AE.    That can be a good thing, since we get more
to give the engine what it needs, rather then a calculaton based on TPS.
But that leads to fly by wire throttles which have to be a better answer
anyway.  With them you can keep the airflow optimised per rpm, per rate of
accleration.  Hmmm, maybe a (3-4", pre turbo) slide like an old SU has isn't
such a bad idea after all............

Then we have to figure in the various drivetrain issues.  Autos being alot
more forgiving then manuals.  With the converter to act as a huge dampner,
we can get the slippage to work for us.  Given enough slippage to get us to
peak torque, where would all this lag even be an issue.
Bruce
    Still cruising in 80s (and earlier) technology......
    Still looking for this *new* stuff everyone's talking about.



From: "James Montebello" <jamesm at undeadminion.bom.conru.com>
Subject: Re: Intake manifold construction, intercoolers
> This is true, but with one big caveat, already mentioned several times:
> throttle response with one "big-arsed" plenum and one throttle will be
> pretty awful.
> james montebello

> On Wed, 5 Dec 2001, Bruce wrote:
> > I was trying to find it, but there is a net site where they get into
> > Hemholtz and manifolding.  On the V6s they contend that two groups of 3
are
> > the best answer.
> >    Needless to say, I'm of the single plenum thought pattern.
> > The closer the runners face an volume of air approaching atmospheric,
the
> > better they will flow.   Of all the manifolding available which
generates
> > both the best torque and HP numbers?.   The lowly Independent Runner.
> > There are several jillion theories as to why, but IMO, it's just a
matter of
> > the air not having to snake around at all to get to the intake valve.  I
got
> > to work with alot of IR manifolds, and engines, and have yet to see
anything
> > approach them.  Now, they use individual butterflies, but the answer to
why
> > is that they have too.  Now how would one try to approximate an IR with
> > Simplicity in mind? (No Correction Needed).   Use your runners and tie
them
> > to a big arsed plenum, and single butterfly.  the large plenum will
> > approximate the atmosphere, or in this case, be the atmosphere, and with
the
> > single butterfly the entering air will have the least inertia, and so
will
> > be able to bend around to  best fill the plenum.
> > Bruce
> >
> >      Note:  The sender is not responsible for your interest or lack
thereof
> > in the contents of this posting.  This Warning is included as part of to
> > ensure that people who ARE NOT LIKE ME are in no way offended or
> > disadvantaged.
> >
> >
> >
> > > Additionally, why two plenums and two TBs?  I can see it if you're
doing
> > > twin turbo but otherwise I don't see it.  I'd just go for the most
direct
> > > means of delivering the air to the cylinder, trying to line up the
port in
> > > the head with the runner as well as possible.
> > > Craig Dotson


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