Date: Wed, 13 May 1998 05:09:32 -0700 (PDT)
From: Dufus McDummy 
Subject: 6 Cylinder
To: dave.williams@chaos.lrk.ar.us

Advanced Engine Technology - Heinz Heisler (SAE Press Paperback)
ISBN 0-340-56822-4   Verrra Good Read - obtain ILL and then buy.

"5.4 Induction valve overlap between cylinders

Induction valve overlap between cylinders occurs when the induction
period of once cylinder commences (IO) before TDC, just ahead of the
induction period completion (IC) on the return compression stroke of a
second cylinder. If the cylinders are joined by a single induction
manifold, the the second cylinder to commence its induction period
interferes with the first cylinder induction period and therefore will
be responsible for the uneven filling between cylinders.

5.4.1 In-line four-cylinder engine

Cylinder interference can be explained by considering a four cylinder
engine having a single riser four branch manifold.  The filling of the
cylinder towards the end of its induction period relies on the kinetic
energy  inertia effect to complete the filling process; its movement is
in opposition to the returning piston at the beginning of its
compression stroke.  If a second cylinder sharing a common induction
manifold commences its induction period slightly before TDC, then the
opening of its inlet valve provides an alternative and easier flow path
into its cylinder due t the partial vacuum created by the outgoing
exhaust gases int the TDC region  just before its exhaust period
terminates.  Consequently, the commencement of the induction period of
the second cylinder, before the first cylinder has completed its
induction period, robs the first cylinder of some of the incoming
mixture column at a critical time just before its filling period ends."

Another excellent reason for the IR system (this time mid high end
power) that has absolutely nothing to do with atomization.  Vizards
exhaust robbing at low rpm + inertia charge robbing at medium / high
begins to explain some of the observed (William O. Mullen) effects of IR
systems.  Let the EFI dweebies try to come close to his numbers and
still idle.  OBTW, a six split into 2 3 cylinders for manifolding
"However, dividing the manifold in half so that a separate riser feeds
adjacent groups of three cylindes completely eliminates induction period
overlap interference".  Does a 300 six or a big bore stroke V-6 begin to
intrigue you?  All the benefits of IR plus helmholz (also explained
complete with formulae and Intake and Exhuast tuned length formulae in
the book).  Wouldn't it be hell if a V-6 or I 6 stomped low mid and even
upper range shit out of a 302?? How could anyone live with that - no
5.0ML content whatsoever.

Any semblance of expertise is an illusion
Habeneros - not just for breakfast anymore!!!