No subject

Thu May 30 05:48:45 GMT 2013

(I did some measurements of an aftermarket computer, and the pulse time
the injector was on for did not vary with RPM (Well, when under engine
vacuum. When under boost it did)

The 32 load points is what several well known computers use (EG
If you're using interpolation 32 wouldn't matter, you might even get
away with something as low as 4 or 8. I'd say 17x17 w/interpolation
should be more than adaquate.
In the initial stages I won't be using interpolation, hence using 32

> >I'm un-decided if an 8 bit injection time will have enough 'dynamic
> >range' from idle to full throttle, though it's probably easier to >deal with
> an 8 bit number.
> My 4 bit linear interpolation code returns a 16 bit result.  I'm sure that 16
> bits is more than needed, and would not be suprised if 8 bits is enough.  I'm
> not that far along to decide (yet...).

I think that the 16bits you get out of interpolation from 8 bit numbers
can still only really be considered to be 8 bit accurate.
HOWEVER, I might well be missing something here (Take the above comment
as being possible/probably incorrect).
If 8 bits is accurate enough for fuel metering there won't be a problem

Anyone else on the list like to comment about their fuel mapping ideas?


pugsley at

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