Intake manifold construction, intercoolers

[Bruce]

From: "James Montebello" <jamesm at undeadminion.bom.conru.com>
Subject: Re: Intake manifold construction, intercoolers
> Thanks for completely omitting the section of my post where I discussed
> the other compromises, Bruce. :-)

Was just trying to tighen up what I wanted to blather about.
Hmm, I thought I had included a brutal snippage comment, but in double
checking, it's not there, that was an error.

> Yes, all things include compromises.  My point was, ONE tradeoff in the
> "one big plenum" approach v. an IR setup is simplicity v. throttle
> response.  There are other tradeoffs.  One big plenum not only makes the
> throttle construction easier, but it also allows you to use MAP without
> heavy filtering (or a MAP plenum).  It allows you to use MAF if you
> desire, unless you make another plenum "above" the throttles in the IR
> setup, where you get the nice airflow without the compromise of losing
> throttle response.
> None of this is new.  IR setups were around decades ago.  I've driven cars
> that were swapped between single plenum/single-throttle setups and IR
> setups.  Throttle response is most definitely improved, so it's not just
> theory.  However, the IR setup is more complicated in many ways.  Whether
> its all worth the effort is up to the guy spending the money.

But, when worded like this it apprears you stating it as a universal truth.
I have no doubt that in some applications there perferred compromises.

> And while you're blathering about drivetrain theory, you should mention
> CVT, where you can tune for a very high but narrow torque peak using 30-50
> year old knowlege to get >150hp/liter out of a two-valve setup, and let
> the CVT hold it on that torque peak.  Nice, once someone figures out how
> to deliver 500+lb/ft through a CVT.  Audi seems to have figured out
> 250lb/ft.  Of course, now we've traded off a simple engine for a
> complicated transmission.

I just find myself limited to what's actually available.  Life's just
complicated enough handling what we have already without further
complicating things with what ifs.
Bruce

 Note:  The sender is not responsible for your interest or lack thereof in
the contents of this posting.  The Warning is included in part to ensure
that people who ARE NOT LIKE ME are in no way offended or disadvantaged.


> james montebello

> On Wed, 5 Dec 2001, Bruce wrote:
> > 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


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