Ok, I have some questions and hopefully you guys can help me out! Bare with me, I'm new to all this economic stuffs..
1. What is timing? How does it benefit FE by advancing it?
2. How does one adjust timing?
3. What is the limit and how do you tell?
4. How much of an impact can it make on FE?
5. Ok, this one might be dumb. Advancing too far will cause detonation, right?
Will using a higher octane fuel solve that problem and thus allow you to
advance more degrees? I might be thinking of that totally wrong though.
Say, +3* 87oct. and +6* 91oct.? Also, will this few degrees more
overcompensate the extra 1.60$ a tank for premium.
Thanks for the information and assistance. This will be for a `95 1.0L manual Geo Metro w/ 120k BTW..
On a metro adjusting the timing is easy, Just twist the distributor housing
This will not actually do much more than move the entire spark table up or down depending on how much you move the distributor off it's factory timing. The cars are set fairly conservatively so you can usually bump the timing up 2-4 degrees with no problems. The only way to find out how much it will help is to test it out. Run a couple of tanks out at 2 degrees advanced beyond factory and if it is better than factory timing. If it is keep adding more timing and testing till your mileage goes down or you hear the car knocking.
You can pick up a few mpg and a bit more power so it is worth doing. It isn't going to make a really huge jump in your mileage unless your timing is already off from the factory settings. To do any of this you really need a timing light and follow the instructions under the hood on the emissions label to set the timing properly.
As far as the higher octane gas, I have tried it and the improved mileage was not enough to offset the cost of the gas, but it was close so it may be dependent on the car and driving style if it works out to be better.
I second your feelings about higher octane gas. I have repeatedly found that in certain engines higher octane fuel pays for itself in better mileage. Everyone should definately A-B-A test that concept on their own engines. Afterward, at least they will know yay or nay.
"You have to know the truth, and seek the truth, and the truth will set you free."
You will have to be the judge of whether you can do this. A timing light is not much money. It really is a very simple operation. I ran my 95 metro at about 6 degrees advance over stock setting. A lot of mechanics won't do this for you. You might have a friend that will.
The altitude and temperature you live at have a significant effect on how much advance you can get away with. Detonation is not always the first problem. Some engines will simply start losing power before they detonate when the timing is advanced too much. I usually try for best power without detonation. I prefer to hear a very slight detonation at hard acceleration with a hot engine. I know that is as far as I can go. That probably produces more NOx than specifications though. Some go to detonation and then back off a couple degrees.
A timing light has a sensor that clips on the #1 spark plug wire. This senor flashes the light when the pulse of electricity is sensed as the #1 cylinder is fired. The timing light then strobes or flashes a light at this point. If you point the light at the crank pully, it will sync with marks on it to show how the ignition timing is set.
Ok, thanks for the information. I might have to wait a few more tanks to see what my max mpg is. If I start doing this now, I wont know how much it effects mpg or if it is being beneficial or hindering me. So, just twist the dizzy? I assume clockwise is advancing and counter-clockwise is decreasing?
Aw damm Sludgy and clencher, you figured me out already? No fun!
Besides advancing the timing, any other simple tricks I can do to the engine?