batch vs. sequential

[eric schumacher]

Hi Bill
The numbers are something else, but the principle is that you want to
control the amount of fuel going to each cylinder.  Presumable you will get
max power when it is optimum/the same for each cylinder.  The problem is
that the contents of the intake manifold ane moveing back and forth as the
valves open and close.  We like to think that the air flows from the outside
world past the butterflys the the manifold in one clean flow.  Such bis not
the case.  The "charge " is moveing inand out like the air in a pipe organ.
Obviously more goes in than comes out, but the second order motion must be
accounted for.

If you use timed injection the runners can be very short because you can
control the fuel very well.  If you use batch injection (Bosch CIS is the
ultimate in this regard) you need long runners to prevent the mixture intend
for one cylinder from being sucked into an adjacent cylinder.

Some of the Bosch books explain this very well.  For a CIS injection system
They state that as a rule of thumb the runner volume of a runner should be
about 1.5 times that of the cylinder it feeds.
Lotsa luck

At 02:38 AM 2/14/97 +0000, you wrote:
>At 02:18 PM 2/13/97 -0800, you wrote:
>>
>>Hello
>>
>>Does anybody have any info as to how much hp gain there is an a normally 
>>aspirated motor with sequential vs. batch injection?  I've heard of 
>>significant gains for emissions and slight gain for fuel economy but is 
>>the a significant gain in performance?  If so how much?  Anybody got any 
>>numbers?
>>
>>thanks 
>>jw
>>
>I currently run a DFI in my 18 ft flatbottom runabout.  Its batch and it
>works well.  I'm considering an FI system for my 454 '74 'vette and I've no
>reason to go with anything else but DFI.  I can't speak for milage or
>emissions as I'm strictly into brute force.  Good luck....
>
>
>                                                                            
>                  Bill
>
>