Originally posted by Dan J
Tell me, how do you “tune” with a computer? Do you plug a wiring harness into the EFI’s computer module and then into a USB port on your PC computer? Do you buy software that is specific for a particular manufacturer’s engine, like a small block Chevy? And how do you program the different setups between a radical 383 and a stock 327? Are you optimizing the fuel mixture based upon the exhaust sensor’s readings? I’m assuming you’d need to put the car on a dyno to tune for power.

If you’ve done all of this, give me a brief lesson in what the process is (real world).

And what about all of the wires for the sensors (like Streets complained about)? Are they two wire (pair) connections, or does the setup require a large wiring harness?

If I go with an EFI setup, it would probably be something like this Hilborn setup... and even if I figure the operational stuff out, I’ll still have to convince my wallet that the expense is worth it

Dan J [/B]
Dan you're not going to like this but that Hilborn has a VERY crude control system using very few inputs (2) and cannot be as efficient as it should be. I looked over the control systems specs and even though they are touting it as "simple as tuning a carb" it could turn out to be a friggin' nightmare if you were to change your setup.

Now to answer the basic questions.

How do you tune with a computer?

Each EFI system has it's own interface but generally you run a cable from a port in the car to a laptop PC. The software is not geared toward any specific size of engine but is instead flexible. You can set air and fuel flow rates in proportion to one another and some systems even alter the timing to go alongside the fuel air setup. Specific tuning generally starts with you setting the air/ fuel ratio far richer than it should be and tuning the fuel down until you get a good air/fuel ratio (typaically around 12:1-14:1). This is best done on a dyno using what is calleed a wideband O2 sensor but can be accomplished by good old fashioned plug reading.

Wires:

Most GM style sensors/senders are 2 wire for coolant temp, air inlet temp and in some cases crank position. Throttle position can be 3 or 4 wire (I think). Knock sensor is one wire. Nothing too fancy.


I hope I at least touched on the answers you were looking for. If not ask again and I'll try to zero in.

Abe