Question about timing

[FyreDaug]

Alright before I get on with the question I should mention I have a good background with motors, however I guess I didnt pay too much attention with ignition timing. I know that the "sweet spot" is the highest operating temp idle you can get by adjusting it. Also from what I understand advanced timing helps low end and retarded helps top end. On my car I have it fairly advanced, maybe 4-6 degrees away from the most advanced it can be.

Now that I'ev put an intake on, I wanna tune it up a little more to see what else I can get out of it. I'm considering advancing it some more because that helps my power, but what about efficiency? I dont want to burn more fuel than I have to get that power. So if I have to take a bit of a performance hit to get some milage I will.

Could someone give a brief explanation of ignition timing, on what does what for rpm ranges? I've searched but my search terms were too broad and come up with 13 pages to go through. I'm at work right now and I dont have a whole lot of time to search through if this has been answered, so I apologize if it has. Thanks guys.

[mouchyn]

ignition timing just changes when the spark is delivered to the mixture. It doesn't have anything to do with how much fuel gets delivered.

[FyreDaug]

I know, but if its less efficient it would consume more fuel because it will take more to be efficient. Not so much but where should the timing be set for most power/efficiency. I would like power all throughout the band, but was I right about advanced is for more power low end? Thats what seems to be the case with me anyways

[A20A1]

The efficiency changes and you don't go as far on the same amount of fuel... but the amount of fuel taken in doesn't change because you advance the distributor unless you're creating some stand off in the cylinders with exhaust gasses. You fire too early and you resist the piston movement durring its compression stroke... too late and the piston is alrealy on its way down.

On the stock accord with the distributor advanced I tested trap speed and it was slower but 60ft was faster. 1/4th mile times were only 0.08 - 0.2 difference.

[Vanilla Sky]

on my friend's 87 LXi, we have the timing all the way advanced, and it seems to want more...

[FyreDaug]

Same with me vanilla, I put it back a bit just because it didnt seem right to push it that far advanced.

[mouchyn]

honda designed the engine to have the best power/efficiency right where the manual says it is. 15* BTDC. advancing or retarding past that setting is going to negatively affect either power or efficiency. if you want the best of both worlds, set it to stock spec. if you want better low end acceleration, advance it some.

[FyreDaug]

I dont have a light so I just go by feel/sound/idle speed. If I advance it from stock would that hurt high end power some more?

[mouchyn]

adjusting your ignition idle without a light is pretty stupid. why not rent/borrow/buy a timing light and do it right?

it's possible you could get some knocking or pinging with the timing advanced too far. that, as we all know, destroys rings, valves, spark plugs, and checking accounts.

[FyreDaug]

Yeah I know there would be something wrong with advancing it too much, thats why I backed it off even though it was running fine. I dont want to risk anything, but I do know it would be more advanced than oem