Re: cheap power

[QSHIPQ@aol.com]

In a message dated 97-05-09 00:39:09 EDT, you write:

<< Not sure I follow the logic behind the reasoning of another valued lister
on
 the problem of "ram" ing the CIS. 
 Assuming all the air going past the flap/metering head goes into the
 cylinders, the flap isn't going to just flap open at high speed. Unless, of
 course, that ram-air is _really_ working well :) 
 In other words, intake valves and/or throttle valve shut, _no air flow_.
 
 Steve Bigelow 
 Ottawa Ontario
 84 5ks, happier this week with a good servo and another (after 4 months!)
 bomb.
  >>
The air flap is drawn open by vacuum, and the demand of the motor is the
"draw"...  Think of (it is) a lever, air demand pulling up the flap, fuel
delivery on the other side of the lever.  Opposite the vacuum is atmospheric
pressure and counter weights that drop the flap by gravity.  When you change
the opposing force to Ram air, you have vacuum on one side and pressure on
the other.  Not the way CIS is designed.  What happens then is the vacuum
actuation on top is lost in favour of pressure actuation on the bottom, by
definition varying by the speed at which you are travelling, always richer,
than what would normally be demanded.  Hardly a accurate fuel metering
method.  The accuracy of that is like sticking your thumb on the bottom of
the flap and guessing where you should hold the flap for a given engine rpm.
 This is a known no-no for years on CIS systems.  You want cold air
"available" not rammed into the flap.  So make a scoop or a dam for getting
cold air TO the air horn.  Ducting it to the flap is not safe at all, O2,
your cat, and backfire forward or into the turbine are risky ways to learn
the wrong way about rich fuel spikes.  

HTH

Scott