1.8 Vs. 2.0 Revisited AKA why 1.8 instead of a 2.0 head

[SCIROCCO_SPEED@msn.com (Brandon Smith)]

That's why I said shape is important.  Much like Carburator Spacers on V8s,
to make the flow turbulent, if you will.

-Brando


----- Original Message -----
From: "T. Reed" <treed2@u.washington.edu>
To: "Brandon Smith" <SCIROCCO_SPEED@msn.com>
Cc: <scirocco-l@scirocco.org>
Sent: Friday, January 17, 2003 4:42 PM
Subject: Re: 1.8 Vs. 2.0 Revisited AKA why 1.8 instead of a 2.0 head


> I feel like I should interject here..
>
> > And yes, I do agree that smaller ports mean a faster air velocity, but
look
> > at the big picture and take into consideration Volume of air moved.
When
> > the exhaust valves are closed, the slight increase in "how quick" the
air
> > reaches the combustion chamber isn't as important as "how much" air gets
in
> > there.
>
> In a normally aspirated motor, velocity is just as or more important than
> flow. The speed of the air coming in is what mixes the air and fuel
> together for good combustion. Accounting for this is what makes the
> difference between a good port job and a bad port job. People that just
> hog out as much material as possible to get the biggest opening will
> probably get more flow but they will decrease the air velocity so much
> that the car will actually make less power because the air doesn't swirl
> around in the chamber when it "hits a brick wall" and mix properly with
> the atomized fuel.
>
>