Vacuum advance tuning to maximize cruise MPG?
Ok,now Im confused. In post 14, you say increase the 22 at the crank you now have. How does that apply to the 18* in the can, now?
EDIT
Ok, gotcha. Still, any idea what that can is out of?
I had a bunch of cans. I sacrificed one of them, and cut it open, to see how the mechanism worked. Theres quite a bit of room to mod the external stop, before running into limits inside the can. I believe my first attempt got me plus 4 degrees. There was a time I went too far and the rotor started to fire to the wrong towers under full vacuum advance. I had to rephase the reluctor. Its a large window but a trick to get centered in it when getting up near 60*. For a while I kicked around the idea of getting a MicroSquirt and support works,to computerize the timing.But in the end I got everything pretty close, and so abandoned the idea.
As I was tuning this can, I discovered that under light loads and throttle settings, the engine responded well to the extra timing while just tooling around.The off idle response was much smoother and the engine became torquier.
Some guys talk about lack of engine braking while tuning this can. Well Im not buying that its can related. Reason being that as soon as the butterflies return to idle the can is out of the circuit. I think they may be starting with too much initial. Thats why I tuned mine from 14*initial. So if you run into that and it becomes objectionable, you might consider backing up your initial some, and filing your stops back. With a manual trans, I really like my engine braking. Passengers hate it.They dont like more than a couple of bunny-hops. I, at least, have the steering wheel to hang on to. My wife wont ride with me much,anymore.