034 EFI

JShadzi at aol.com JShadzi at aol.com
Wed Dec 5 01:05:45 EST 2001

Don't make me repeat my "knock-sensor-saftey-device-bandaid" speech, you
don't really need it to get started...


Ok, not sure I followed your whole though process, but basically each
injector opens once each time each valve opens.  That is what Sequential
injection is all about, and what makes it advantageous over batch fire
systems is that enough fuel is injected for _each_ valve opening.  The timing
is not really critical, especially at high RPM, as the injectors are open
most of the time anyway, so fueling starts becoming continous in nature (as
in all EFI systems).  EFI injectors have very good atomization of fuel, so
things like pooling etc. need not be worried about.

Now, the newer EFI systems like Motronic time the injector with the valve
opening, but it does not mean that the injector is necessarily opening when
the _valve is_, that is a very big misconception.  Proper atomization,
tumble, injector placement, and actual fueling can vary greatly per the

Valve-timed sequential injection is advantageous in very low speed engine
operation (like idling) and in reducing emissions by more tightly controlling
how much raw fuel will actually make it into the combustion chamber.

To program a system like Motronic, especially the newer versions, is more
complex that even what most of the big tuners make it seem.  A valve-timed
system like Motronic has layers and layers of maps, which can only be tuned
after thousands of hours of testing.  One change in a variable will affect
hundreds of other map-layers, taking into account all the changes is a very
big job.  Basically, a true timed system is out of the range of expertise
that I have or most people who do not have education and experience to do so.

BUT, you don't really need to worry about any of that, my 50k+ miles of
testing along with many other cars on the road, plus the many factory EFI
systems show that non-timed sequential injection is a very good way to fuel



In a message dated 12/4/2001 7:28:39 PM Pacific Standard Time,
auditude at neta.com writes:

<< Maybe I can get a J&S Safeguard and run the stock 4ksq ignition
 with it?  That could be where the money not spent on a MAC11
 chip mod can go.

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