I'm just curious.
How does advancing the ignition effect horsepower, and fuel efficiency?
It seems to me that a lot of the people here keep recommending over and over to connect the vacuum advance to manifold vacuum. But that doesn't seem right to me.
I was told by someone else that "the vacuum advance is supposed to advance the spark during non-load situations for better fuel economy.
If this is correct, then it means that the engine puts out more power when the spark is not advanced, and produces better fuel economy when it is advanced.
From the page about tuning Holley carbs at:
http://www.bob2000.com/carb.htm
"The other type of vacuum connection on a Holley is ported vacuum, which is weak at idle, strong at cruise, and weak at WOT."
This means that there is no advance at idle, lots at cruise, and none at WOT.
idle - no advance - no load
cruise - lots of advance - low load - good gas mileage
WOT - no advance - high load - lots of power
So, if no advance means more power, then why would so many people keep saying that on a high performance engine with lots of horse power one should connect to manifold vacuum?
Basically I don't understand this crap at all.
How does advancing the ignition effect horsepower, and fuel efficiency?
It seems to me that a lot of the people here keep recommending over and over to connect the vacuum advance to manifold vacuum. But that doesn't seem right to me.
I was told by someone else that "the vacuum advance is supposed to advance the spark during non-load situations for better fuel economy.
If this is correct, then it means that the engine puts out more power when the spark is not advanced, and produces better fuel economy when it is advanced.
From the page about tuning Holley carbs at:
http://www.bob2000.com/carb.htm
"The other type of vacuum connection on a Holley is ported vacuum, which is weak at idle, strong at cruise, and weak at WOT."
This means that there is no advance at idle, lots at cruise, and none at WOT.
idle - no advance - no load
cruise - lots of advance - low load - good gas mileage
WOT - no advance - high load - lots of power
So, if no advance means more power, then why would so many people keep saying that on a high performance engine with lots of horse power one should connect to manifold vacuum?
Basically I don't understand this crap at all.