figuring out advance timing
Maybe he'll report back, as my last suggestion was to make tweaks one at a time and see how that effects performance.
By performance many people go seat of the pants but that's not what I mean.
I mean verifyable efficiency; such as
.. best mph in the quarter or power curve on a dyno establishes the best timing at wide open throttle, mid to high rpm.
..lean cruise at steady interstate speeds that runs without issue on the fuel available. (Too lean the engine will surge & too much timing you'll hear a gurgling or light pinging)
In the link above, this one Timing advance guru input needed
is a conversion for MAP to Vacuum. That helps me and maybe it will help you.
In posts #9 and 10 above, the light blue column is the conversion to vacuum.
So yes I think Backalley's post 13 is much closer to what your the engine will want. Copying that would probably be a good baseline.
Some comments about your current timing map:
I don't see any reason why the engine wouldn't start with 12* BTDC
I also think with that setup, its not that efficient at idle more time will be needed to burn. Timing around 18* for the slow idle rpm is probably a reasonable baseline.
The arrow points the rows I *think* are around zero vacuum. From 0 to 3" Hg is the equivalent of the mechanical timing in a distributor.
Standard Chrysler engines like quick advance to 1800 rpm or so, then slower advance to higher rpm.
I've pencilled in some numbers to illustrate.
Below 50 kPa should be the equivalent of full vacuum advance. At low throttle position, depending on the engines part throttle efficiency and how lean the mix is, the flame burns much slower so additional lead time is needed. I've penciled in some numbers to give some idea. (At idle rpm the engne is not making much power and a rich mix can help, so no vac advance is needed. If there are emissions requirements you'll have to make it leaner)
This is just basic concepts to get you in the right direction.
@TT5.9mag can probably provide more specific guidance.
Maybe he'll report back, as my last suggestion was to make tweaks one at a time and see how that effects performance.
By performance many people go seat of the pants but that's not what I mean.
I mean verifyable efficiency; such as
.. best mph in the quarter or power curve on a dyno establishes the best timing at wide open throttle, mid to high rpm.
..lean cruise at steady interstate speeds that runs without issue on the fuel available. (Too lean the engine will surge & too much timing you'll hear a gurgling or light pinging)
In the link above, this one Timing advance guru input needed
is a conversion for MAP to Vacuum. That helps me and maybe it will help you.
In posts #9 and 10 above, the light blue column is the conversion to vacuum.
So yes I think Backalley's post 13 is much closer to what your the engine will want. Copying that would probably be a good baseline.
Some comments about your current timing map:
I don't see any reason why the engine wouldn't start with 12* BTDC
I also think with that setup, its not that efficient at idle more time will be needed to burn. Timing around 18* for the slow idle rpm is probably a reasonable baseline.
The arrow points the rows I *think* are around zero vacuum. From 0 to 3" Hg is the equivalent of the mechanical timing in a distributor.
Standard Chrysler engines like quick advance to 1800 rpm or so, then slower advance to higher rpm.
I've pencilled in some numbers to illustrate.
Below 50 kPa should be the equivalent of full vacuum advance. At low throttle position, depending on the engines part throttle efficiency and how lean the mix is, the flame burns much slower so additional lead time is needed. I've penciled in some numbers to give some idea. (At idle rpm the engne is not making much power and a rich mix can help, so no vac advance is needed. If there are emissions requirements you'll have to make it leaner)
This is just basic concepts to get you in the right direction.
@TT5.9mag can probably provide more specific guidance.
