Help Creating an Ignition Map for a 1965 Corvair (NA)

[mechanicalman]

Hey guys, I just got my setup installed in my car and I've been using it to monitor engine behavior, but have yet to pull the distributor and connect the coilpack to have megajolt start managing ignition.

I downloaded the excel spreadsheet that's supposed to help come up with a table, but I just don't have any good information describing the vacuum curve of the stock engine.

I included a picture of the page from my factory manual that describes the distributor specifications and I came up with the following entries for the vacuum map in the excel spreadsheet


kPa--degrees
24--10
30--10
40--10
50--10
60--6
70--2
80--0
90--0
100--0
102--0


The centrifugal map was pretty obvious and I don't have any questions about that, but I just want someone who knows to tell me if I interpreted the specs from the factory manual properly. It describes vacuum advance starting at 7 In Hg (78 kPa) and full advanced being reached at 15 In Hg (51 kPa).

BTW, the specs for my engine are listed under the last column for the 110 HP version.

[mechanicalman]

Well, here's what I came up with using the Excel spreadsheet to plot it out. I included screencaps of the two curves I came up with that are essentially exactly what the factory manual specified, but it seems really hot in the upper right corner. The stuff in the 800 rpm column I based off of miniman82's map, but his was a turbo and mine isn't. I couldn't really find a lot of guidance in terms of making provisions for the advance at idle, so I'd appreciate some advice toward that end. Just really any advice at all before I burn a hole in a piston.

Idle at 650 rpm produces a vacuum of about 58 kPa.