DIY_EFI abilities and older engines

David Doddek pantera at dris.com
Tue Nov 28 04:17:17 GMT 1995


>	I am fairly new to the list and have read with interest the discussions 
>about diy_efi and older engines. I am currently working on a senior design 
>project to design and operate an injection system on my 1963 Corvair. The 
>Corvair currently has the original dual carb setup. I plan on replacing the 
>carbs with throttle body units from a General Motors 1.8 or 2.0 engine. I do 
>have a microprpcessor unit made by a company which is no longer in business 
>( which may not bode well for my system but we'll see...) it is based on the 
>Hitachi 64180 (a z80 clone??) it has 24 I/O lines with an 8 input A/D 
>convertor on board as well as the ability to burn eproms. The questions I 
>have are: how much will I have to worry about ignition noise ( I plan on 
>leaving the current timing setup alone that will have to be dealt with 
>outside of my project). Also I plan on using a MAP sensor to determine 
>engine loading. The information for the fuel map came from a General Motors 
>Stock Engine Test Report that I obtained from an aftermarket Corvair parts 
>vendor  ( the same reports may be available for older V8 engines but dont 
>ask me where you could look I am strictly Corvair). If anyone has any 
>comments or advice it would be very much appreciated...
>
>
>
Fun project, I did EFI for my senior project.  You did not say if the
processor was a complete board or just the chip.  If it is just the chip,
keep the component count to a minimum and connection paths short to help
prevent noise from the ignition.  Use decoupling caps in several places in
the power supply including one at each chip as close as possible to the
power pins.  About .047uf. If you use low inpedence injectors (2.4 ohm), use
a peak and hold type of injector driver, (Motorola MC3484).  For high
inpedence (12 ohm and up) just saturate with a transistor.  I don't know
much about the your processor, but it may be hard to find an assembler or C
compiler.  You may even want to think about throttle body injection for a
first try.  It makes the manifold simpler and really effects the general
operation of the engine little.(no flames on port vs TBI please, I know the
advantages of both)  Good luck and have fun driving a more pleasurable car.

Hope I was some help.

David J. Doddek                                          |pantera at dris.com
Owner SGD Electronics & Development Engr for Caterpillar |h 309 685-7965
Formula SAE Team Sidewinder 94-95                        |w 309 578-2931
89 T-bird SC,  69 Fairlane w/SGD EFI                     |fx 217 428-4686
74 Pantera w/Electromitive Tec-II Twin turbos and Nitros |
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