Tapered intakes, port velocities etc.

[Frank/G.speed]

> One "rule" about flowing heads is that you want as much low-lift flow as
> possible. I never came across any reasoning behind the statement. The
> way I saw it was that you have the smallest pressure differential when
> the valve is first opening, and thus, the least potential to flow a/f.
> What I didn't take into consideration was the flow through the valve
> while it was closing, when the interia of the a/f mixture is probably
> close to its maximum. It sounds like a large part of the cylinder
> filling may happen when the valve is closing/near closed.
 
[tech-wannabe-with-no-credential-opinion-mode-ON]

A main factor is because the valve remains open longer at the lower lift
(the valve opens and closes).  The time spent at maximum lift is much
shorter than at low lift. 

PS, Much thanks to Todd for the article.  I have had a chance to read it
yet...  only caught part of it at a quick glance.  A friend of mine is
doing some experimental port work and I'm sure he'll appreciate some
insights from this paper.

Any of you have experience with Honda B16A3 engine?  1.6 DOHC VTEC...
Seems like some of you had played with Toyota 4AG(E) a bit.  Maybe
you want to share some secrets?  :)

-- 
Frank M. Lin	   | G.speed - Z.Speed Trust HKS DC-Sports Razo/Carmate Soei
fmlin at ccnet.com    | Web page - http://www.winternet.com/~fmlin/gspeed.html
EG2, 15.3 @ 91 MPH | Info sheet - "finger fmlin at ccnet.com > gspeed.info"
u ssim I enirehtaC | Wanna try road racing with your car? http://am.net/nasa