Intake manifold construction, intercoolers

[Bruce]

From: "Bernd Felsche" <bernie at innovative.iinet.net.au>
Subject: Re: Intake manifold construction, intercoolers
> Bruce tapped away at the keyboard with:
> > From: "Kevin _" <kiggly at hotmail.com>
> >> And when you're making a high rpm engine you keep the valves
> >> unseated for over 300 cranshaft degrees.  Usually about 250 to
> >> 260 degrees for 0.050" valve lift or more.  The more/less air
> >> being packed at a certain time during the intake stroke is no
> >> different at all for a turbo or non-turbo engine.  The only
> >> thing you design slightly differently for a turbo is the speed
> >> of sound is higher because the intake air temp is higher in a
> >> turbo application.  Thus, you need slightly longer runners for
> >> the same Helmholtz rpm, but its nearly inconsequential.
> > Higher rpm, OK, how high are you talking about.  The thread
> > started with street cars, are you still working the street or
> > moving into the race field I'd hardly call 250d at .050 as a
> > street engine.

> Depends on number of cylinders and method of induction.
> My 4-cylinder car's NA with 270 degrees and more than 10mm lift.
> It's only a bit lumpy at idle.

270d @ .050 clearance?
270 @ .005 maybe.

> >>>If atmospheric pressure doubled, I don't think it will make an
> >>>appreciable difference in the way an intake manifold worked.  The
> >>>whole question still seems inconsequential to me, since by tuning
> >>>an intake you are trying to increase intake air pressure by a
> >>>small number of pascals.
> >> Have you ever datalogged and seen pressure pulses at the back of
> >> a valve?  When its all tuned right with the proper sized runners
> >> it can be over 20% beyond atmospheric pressure during valve
> >> closing.  We're certainly not talking single Pascals here.
> > At the back of the valve, OK, and how fast does that decay as you
> > move back from there?
> Doesn't matter. It's the pressure at the back of the valve that acts
> to fill the cylinder.
> >> BTW - Bruce said he was looking for 'new' stuff in engines.
> >> Check out F1 stuff before you call everything old and pushrods
> >> good.  Approximately 300hp/liter naturally aspirated on gasoline
> >> (yes, I do use that term loosely) and revving to near 20k rpm
> >> isn't trivial.
> > To whom?
> > I haven't seen any of that wizz bang technology filtering to
> > anything on the street yet.  They still have reached any level of
> > performance that can't be done with engines that would have
> > transferable technology to the street.  The rules in F1 are just a
> > game anymore to see who can spend the most for something that can
> > win.

> Same in all motorsports.

So we're again going off on tangents.

> If you want to see how much of that technology is filtering down
> into production cars, I suggest you browse through SAE's Automotive
> Engineering magazine occasionally.

> Cars built on space-frame: yes - FIAT and Audi
> Multi-valve engines with variable manifolds: yes - most manufacturers
> Dierect gasoline injection: yes - Toyota, VW-Audi, Mitsubishi
> Turbo-multivalve engines: yes - Volvo, VW-Audi, Subaru, etc.
> Independent cylinder throttling: yes - BMW (3 series and 7-series)

We were talking engine technology.
F1 didn't discover multi valves.
Direct injection has been used for years in IH tractors, and the 300SL did
also.
2 models of one manufacurer, OK, but big deal
Bruce


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