don j - hope you don't mind me taken this well written post of yours to help me to help bring this EFI discussion back down to earth. i think not knowing or not understanding it, is what's behind the hesitation to get into it right now, because its one of those deals if you ever got used to it you wouldn't every go back. its a little more cost involved at first but then its almost maintenance free. you will need a good scan tool and know how to read it. ill try to answer some of your ?
dan j- Some folks around here know that I've been lusting for one of those Hilborn EFI’s for some time, so I’ve been trying to figure out all of the ancillary work involved in getting an EFI system to work properly. And from what I’ve learned so far, it’s a whole lot more difficult to convert a carburetor system to EFI than to build your project from the beginning with an EFI system in mind.
mike- if you don't wont to pay for a new system, go to the junk yard a buy the intake, sensors, and wiring harness for about what you would pay for a carb. youll need a good wiring diagram also.
dan j- What I like about EFI (the Hilborn setup is icing on the cake) is that you can accurately fine-tune the system to provide the optimum air-fuel mixture for power (or efficiency) across the entire power curve of an engine. The down side appears to be “that it ain’t simple” for the average person to tune (or program) the system.
mike- that's the whole idea of EFI. there should not be any wasted hp with a well tuned EFI. I'm using a 1993 computer so I can buy a chip to go into my computer that can be programmed to do most anything you wont it to . 1994 up gm computers and most of the after markets computers has to be reprogrammed as a unite.
dan j-But before you even think about the tuning (or computer programming), you’ve got to have the right electrical and fuel plumbing system. There is a computer module and an array of sensors: O2 sensor to read the exhaust and determine if the air-fuel mix is too rich or lean, a manifold pressure sensor, an air inlet temperature sensor, and an engine coolant temperature sensor. And since the EFI system also controls the ignition timing, your ignition system is going to have to be compatible with computer controlled EFI too (no vacuum or mechanical advance).
mike- true, but just think how much better it can get later on down the rd. there is no end to the tuning part.
dan j-What else is unique for the EFI system? You've got to have high-pressure type supply and return fuel lines (50 psi vs. 5 psi for carburetors), a special fuel tank with a sump (or modify your existing tank), a surge tank to help prevent air from being sucked into the fuel line, a fuel pressure regulator, special fuel pump, and special fuel filter. And also, your electrical system and wiring need to be in very good shape... static or noise in your electrical system will mess with the computer module!
mike- don't need a special fuel filter or fuel tank with a sump (or modify your existing tank) a surge tank to help prevent air from being sucked into the fuel line. have not seen any problems with static or noise in your electrical system thatl messed with the computer module yet.
danj-I’m awfully intrigued by the EFI systems, but my ole geezer head has got some more learning to do. Maybe one of the young fellows can help to convince me that it's more simple than it looks
mike (old geezer) i was to, but now im running EFI on everything. what's a carb?????
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