[Diy_efi] Flap-type Airflow Meters/Data logger

[Steven P. Donegan]

Funny how great minds think alike :-) Take your typical shop vac - use
the 'blow' side of it as input to a throttle body, followed by MAF#1,
followed by MAF#2 - log both... Given a known table for MAF #1 (the GM
one) you can build a reasonably accurate starting point set of tables.

The re-design (circuitry) of the MAF translator to serve as a really
cheap data logger is 95% complete. C (I finally settled on the CCS C
compiler - 145$ for those that want to work on this hands-on) code for
5(ea) A/D channels, 2(ea) frequency/period channels (one for MAF
frequency, one for capture of injector pulse duty cycle) is ready to
test on my proto board this AM. The final data input for this board
which is 'wired' so to speak but not C coded is the interrupt which will
capture RPM/Crank TDC events. This is all based on my original PIC
16F876A microcontroller. I may just use it as a front-end to my bigger
EFI project - but for now it can just be a data logger. One more thing -
it has the outputs wired for RS-232 (for data logging) and LCD (for
in-car real-time display). The RS-232 is coded, the LCD output is not.
Initial board layout had the whole thing at 1.4 by 2.3 inches. I will
check my Jameco catalog for a good board size to fit an all-metal
enclosure and then use that board size...

Adam - this logger should be of equal use on the Bike project - ie go
ride the heck out of the bike and you capture all sensors/all outputs
and build a 'stock' set of maps...

On Tue, 2007-01-23 at 21:21 -0800, Adam Wade wrote:
> --- "Steven P. Donegan" <steve at donegan.org> wrote:
> 
> > I am adding an RS-232 port to the MAF interceptor so
> > folks can customize this mapping any way they wish.
> 
> I was actually hoping for separate tables, one for the
> actual conversion numbers and one for "trimming"; that
> way you can set the device back to "zero" (same
> response as the stock flapper) without needing to
> re-load the calibration.
> 
> FWIW, I intend to write software for your box that'll
> let you wire both the MAF and the flapper at the same
> time, so you can put the MAF before the flapper and
> then just data-log and build a conversion table for
> your particular flapper from that.  Should be
> relatively simple to do, and I could even have it
> automagically make the finished table for use in the
> working converter device, saving a lot of muss and fuss.
> 
> | Kawasaki Zephyr 615 (Daphne)       Kawasaki Zephyr 550 (Velma)|
> | "It was like an emergency ward after a great catastrophe; it  |
> |   didn't matter what race or class the victims belonged to.   |
> |  They were all given the same miracle drug, which was coffee. |
> |   The catastrophe in this case, of course, was that the sun   |
> |     had come up again."                    -Kurt Vonnegut     |
> | M/C Fuel Inj. Hndbk. @ Amazon.com -  http://tinyurl.com/6o3ze |
> 
> 
>  
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