Pro Flo 4 Timing
Today I finally was able to drive the car, and saw some interesting behavior, similar to the one posted by a member on a video on this thread.
The vacuum readings are off, which confirmed what I suspected in why I had to pull the timing back so much to make sure the engine stays smooth at WOT all the times and avoid thos small hesitations I felt sometimes when getting close to the RPM limit.
When the engine was not running you can see it reading -5.9 of vacuum already. (see attached pic). At WOT the reading is around -7 inches of vacuum, so if I have -5 vacuum advance that is adding 1.2 degrees to my top RPM based advance. when I had that set at 34 or so it was really going to 35-36 or so. At cruising or when releasing the pedal with no load most of the time my vacuum reading is between 15-19 inches of vacuum.
Since gas quality here is not as good sometimes here and my compresion ratio is rather high (12.5:1) I will change the parameters in a way that at WOT I will have around 32 degrees total and plus 10 degrees more at -30 inches of vacuum.
For what I read in the edelbrock forums the vacuum advance is linear from 0-30 inches, so whatever max value you put in there will be applied linearly additively all the time the engine is running as long as you dont have 0 inches of vacuum, so be mindful of that when setting your parameters.
I hope the info helps.
Today I finally was able to drive the car, and saw some interesting behavior, similar to the one posted by a member on a video on this thread.
The vacuum readings are off, which confirmed what I suspected in why I had to pull the timing back so much to make sure the engine stays smooth at WOT all the times and avoid thos small hesitations I felt sometimes when getting close to the RPM limit.
When the engine was not running you can see it reading -5.9 of vacuum already. (see attached pic). At WOT the reading is around -7 inches of vacuum, so if I have -5 vacuum advance that is adding 1.2 degrees to my top RPM based advance. when I had that set at 34 or so it was really going to 35-36 or so. At cruising or when releasing the pedal with no load most of the time my vacuum reading is between 15-19 inches of vacuum.
Since gas quality here is not as good sometimes here and my compresion ratio is rather high (12.5:1) I will change the parameters in a way that at WOT I will have around 32 degrees total and plus 10 degrees more at -30 inches of vacuum.
For what I read in the edelbrock forums the vacuum advance is linear from 0-30 inches, so whatever max value you put in there will be applied linearly additively all the time the engine is running as long as you dont have 0 inches of vacuum, so be mindful of that when setting your parameters.
I hope the info helps.