My EFI is alive!

[Chris Vondrachek]

Dimers,
	Well I did it!  My totally homebuilt EFI project lives.  After fouling 3
sets of plugs, the engine fired early friday morning, and boy does it purr.
 I still have lots of tuning to do...the fuel map is really rough and the
O2 sensor correction doesn't work right....oh yeah there is no acceleration
enrichment...yet.  But other than that it is totally functional, it really
does work well.  So like I promised...here are the details:

Engine:
 Block/Head-
	Z-22S block (+0.020), U67 head, 270/0.450 cam, ~10.6:1 
 Intake/Exhaust-
 	280Z intake cut and welded, Z-22E throttle body, L-16 cast manifold (O2
sensor in down pipe)
 Ignition-
	stock breaker points - a really wacky distributorless igntion is in the
works though

EFI System:

TYPE:
Batch firing Speed-Density (uses manifold pressure and rpm w/ air temp to
get mass air flow....no MAF box needed, 2 injector events/revolution, all
four injectors go at once (soon to be changed))

COMPUTER:
custom designed by me, based on Motorola 68HC912B32 16 bit/16 MHz MCU
32 kbytes Flash EEPROM, 2 kbytes RAM, 768 bytes EEPROM.

SOFTWARE:
also written by me, over 5 pages of assembly code plus 2 fuel maps

SYSTEM HARDWARE:
Motorola MC33293 quad fuel injector driver, misc signal conditioning, power
supply and filtering circuitry all in a Radio Shack metal project box :)

SENSORS:
manifold abs. pressure (MAP), manifold air temp (MAT), coolant temp, Lambda
(O2) system triggering/rpm signal from coil.  (MAP, MAT, and CLT are GM, 02
is Bosch)  

INJECTION STUFF-
4 Bosch injectors out of a Z-22E, also a cold start injector in the plenum,
Nissan fuel injection pump (~60 psi), system pressure 40 psi, pressure
regulator, custom tube fuel rail, idle air valve set for about 5 minutes
from cold.

FUEL MAPS:
2 maps: base map and correction map, user defines base map used for open
loop, computer modifies correction map to compensate for above map and
"other" factors when in closed loop operation. user can modify and reload
base map in 10 minutes max. allows sloppy rich or lean and clean A/F
settings.  10 MAP levels, 15 rpm levels (will be 15 map levels and 10 rpm
levels soon), maps stored in EEPROM for easy modification.  lots of changes
to come in this area....
  
Next step is finshing/refining the system including testing, bashing,
dropping etc to see if I can get the system to hicup.  If not the next
phase is to pull the engine off the dyno and drop it into my 2dr for some
serious performance analysis :)  It will be at Shasta...heck, I might even
have the turbo on then too...ah we'll see (10.6:1 + 7 psi = knock, knock,
clank!).

Well those are just a few of the details :)  If anybody has any questions,
comments, political statements etc I'd be happy to hear 'em.  And yes I do
have some pictures of the more important processes...when I get them
developed and scanned....I'll post.
	
Chris "EFI'd" Vondrachek
  

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Chris Vondrachek  
chris at egr.up.edu

winter: EE student (junior), University of Portland 
	 President & Founder of the U of P Formula SAE Team
summer: Datsun 510 nut, in my garage: Newberg, Oregon	

'70 2dr 510 - (soon to get a EFI'd LZ-22)
'71 4dr 510 - (will get hand me down L-20B from above)
'71 2dr 510 - (race car project...someday)
'73 2dr 510 - (parts car)
'85 VG30E - (twin turbo EFI engine by Shasta '99.....or I own Kelvin a pizza)