MSD 6530 with MAP sensor

[DanEC]

Lippy - that sounds like a really nice unit that is easy to play around with. Impressive to the old points and condenser guys like me.

[lippy]

Here are the photos:

(1) My method of locking the distributor, which I think is far easier than what MSD recommends

(2) The MAP sensor, insulated and mounted on the small stainless bracket I welded up

(3) The curves I'm using on the 6530 ignition box. The way this works is that you set the maximum timing, in this case 47 degrees, and the timing on the graphs is taken out of the total. Also note the vacuum curve is in PSIa, and not in Hg. It's easy to convert (e.g., 8.5 PSIa is 17 in Hg and 10 PSIa is 9 PSIa).

Vacuum Conversion Calculator

[Gaz64]

Originally Posted by lippy

Also note the vacuum curve is in PSIa, and not in Hg. It's easy to convert (e.g., 8.5 PSIa is 17 in Hg and 10 PSIa is 9 PSIa).

Vacuum Conversion Calculator

Not quite correct there.

Here is my table:
psia inches Hg
0----- 30
1----- 28
2----- 26
3----- 24
4----- 22
5----- 20
6----- 18
7----- 16
8----- 14
9----- 12
10---- 10
11---- 8
12---- 6
13---- 4
14---- 2
15---- 0

So 8.5 psia is 13 inches Hg, and 10 psia is 10 inches Hg.
By coincidence 10 is 10, but in any direction, the figures are obviously different.

5 inches Hg (typical Holley power valve) would be 12.5 psia.

Hope this helps.

Gary