I didn’t see this thread until I was just reading over one I started on "projects" section.
I was over reading your guys thoughts about EFI stuff, I wanted share some of my thoughts to. ( Sorry if this might seem long, I think its great information for topic )
On side note I just bought
www.extremefuelinjection.com :weld::weld::weld:
SO haha! , this site will be my EFI project site, anyways...
The system I am designing is simple (so I like think). I would control both fuel and spark. Purpose behind controlling spark, was for fact I can slap a Ford EDIS unit on any motor and get a clean tach single back off of it, plus I can control timing advance/retard by yet another pulse back into the module.
This is optional to do, I wont get into this sense we are talking about just EFI.
What I want share light on is how the Fuel Injection would be working and exactly what hardware I am using.
Hardware:
Fuel Pump/Injectors/Regulator: GO look on ebay for any EFI'ed motorcycle, 1000CC bikes seem have EFI on them, I got my parts off a VR4? Honda something, for 20 bucks I got fuel pump, 4 injectors, fuel rail, fuel regulator. Now you cant beat that!, do math each 4 injectors in a 1000cc 4 piston engine, each injector can run a 250cc size motor no problem, and up to whatever god 10,000++ RPM. And fuel pump draws around ~3 amps? at 30psi...(note the injectors are TINY, great for mounting)
Air Meter: Ford Escort 1.9L (90~95) Mass Air Flow meter. These units come in there own housing, you can unscrew the two screws and take the meter off the housing, Its a 2-wire meter, if you look closely there is a little smaller metal tube the wires plug into besides the main opening on the housing, on my motor I machined my own 1" di housing and made a little 3/8's tube similar to one on real deal. I tested it, works great! on my 6.5 clone I get .8 volts at idle and 2.5 at wide open, what all that means? nothing just gives me analog voltage for measuring the engine load, of course when boosting I still have another 2.5 volts of air flow to go! :smile:
Temp sensors: anything can work here, coolant sensors, air temp sensors, as long as my computer can figure out hot between cold, thats the real main thing. They call this "Enrichments"
Throttle Position Sensor: Optional in my opinion, I don’t think these motors would need this, just richen the mixture a little and any tip-in throttle movements, motor wont lean out, yet you may still need one ...
Oxygen Sensor (O2): Optional, I doubt any O2 sensor could read gas correctly sense you are measuring just one piston, and at lower rpm you might read the atmosphere air outside the pipe and get misleading information.
Exhaust Gas Temp sensor (EGT): This is the way to tune a motor in my little world. You dial your motor to run at a certain temp, plus if you tune it wrong, the temp will be wrong (example run WAY hot). Also different types of fuel will tend to run at different temp's.
That’s it!!! well and fact you need a computer based controller to make it work, I think someone mentioned a analog based EFI controller, GOOD LUCK! BOSCH made one for BMW's and whatever else, monotonic something jet, bunch of transistors and resistors/caps, its not impossible, but I rather "flip bits" then try debug a analog circuit, any day! :hack:
I won’t get into to much detail about how EFI computer could or would work, basically you just have a 2d fuel and or spark map (engine load / engine rpm) and punch numbers in the "map" to tune it. Simple as that, then add your enrichments (throttle position/engine temp).
Agian this is just for information purpose, it sounds great and simple, I guess if I were to do it correctly, make a Clone Bolt on kit perhaps? and package it under 100 bucks ( which was the goal), it might seem attractive, I am leaving out more details about how end user would install/tune it , laptop?, programmer?, pre-programmed?, who knows... And another question might be where get the electrical power to run the system, go Google Li-Po batteries, great source of larger current power for low space/weight applications...
Sean-