What I am wanting to know is What Functions regarding Tuning does and aftermarket Tuner provide, that the ECM does not.
It's difficult to explain to someone what exactly the tuner can do, if you do not know yourself.
You might get better information if you clarify your terms a little. What do you mean by "aftermarket Tuner"? Technically, anything marketed by anyone other than H-D is "aftermarket", and this encompasses everything from piggyback units (things that plug into the wiring harness, usually between the harness and the ECM), to devices with which to reprogram the stock ECM, to complete replacement ECMs (like TMax, DTT).
Naturally, the OEM ECM "provides"
everything, but it might not be correct for any particular situation or combination of parts thrown onto the bike after it left the dealer the first time. No piggyback will bring anything extra to the table, nor will any reprogrammer, while a replacement ECM might if it trades, say, MAP-based fueling and/or ignition timing for extended closed-loop coverage.
Can you balance each cylinder, ie Firing pressure, Fuel pressure and F/A Ratio?
With the second and third possibilities I listed above, you can do all of those things apart from fuel pressure. Nothing will alter that except for a completely different fuel pressure regulator in the fuel tank if you want to increase it, or I suppose inside or outside the tank if you want to
decrease it (though excess pressure would have to be returned to the tank...).
Depending on the complexity, and that varies widely, a piggyback controller might be able to perform anywhere from all those tasks (except fuel pressure) to just some of those tasks.
By doing the above, can you control exhaust temps?
You can control exhaust temperature by altering either the fuel mixture, the spark timing, or both. Again, the reprogrammers and replacement ECMs can handily do this while the piggybacks can variously perform those operations.
What exactly does adjusting those "Pots" do for you?
I haven't a clue what you're referring to. It sounds like simple controls on a simple piggyback
fuel only controller like an early-generation Dobeck or its various other incarnations.
What extra Bells & Whistles does a High Dollar Tuner have over a moderately priced Tuner?
That question is much too vague to answer.
For your situation, your piggyback unit is a decent way to go for the money, no doubt about it. You'd have to invest a fair sum to truly upgrade.
Your neighbor has what is currently "state of the art" for a Harley with his closed-loop Delphi engine control package. If he's running around with intake breather and exhaust changes (especially if it's more than just replacement mufflers) without having reprogrammed his ECM in some way, he's at a minimum leaving a lot on the table and at a maximum bordering on foolishness. How has he determined he's at 13:1 "AFR"? Was it measured or is he merely taking someone's word for it? At any rate, that's a bit rich for "cruising" and a bit lean for "hammering".
I'm a firm believer that if you've got a Delphi ECM (of any generation) on a Harley, the absolute best thing to do is get a kit with which to reprogram the ECM to match your specific needs, and my favorite is the TTS by mastertune.net. Piggyback controllers are inelegant at best and only go downhill from there in my estimation.
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Topic: ECM vs Aftermarket Tuner (Read 3415 times)