How much vacuum does a naturally aspirated engine have at idle in the intake manifold?
Normal manifold vacuum at idle for an engine in good condition is about 18 to 22 in. -Hg.
Why are there so many vacuum lines coming off the intake manifold?
So why do I have so many vacuum lines coming off the intake manifold? Well, this is because that is where the vacuum is present. Since the intake manifold represents the area behind the throttle plate, the highest vacuum that the motor produces will be found in the intake manifold.
Where are the outlet ports on the intake manifold?
Because of this, the intake manifold will often have many vacuum outlet ports found on it. Vacuum Accumulator / Vacuum Box Some custom application intake manifoldsor those manifolds equipped with individual throttle bodies, do not have enough room to accumulate sufficient engine vacuum.
Why did Ford use 2 vacuum lines in the engine?
This is ancient history to me but I believe the reason for 2 vacuum lines was because Ford used a dual-diaphragm modulator valve that was supposed to help shifts and in turn aid emissions. This used both manifold vacuum and ported vacuum from the carburetor body and did not work too well.
What does the vacuum line on a truck mean?
The vacuum lines to the transmission tell the transmission’s vacuum modulator how hard the engine is working. Low vacuum means it’s working hard, because you have the throttle open more, high vacuum indicates the engine is not working hard because the throttle is closed more.
So why do I have so many vacuum lines coming off the intake manifold? Well, this is because that is where the vacuum is present. Since the intake manifold represents the area behind the throttle plate, the highest vacuum that the motor produces will be found in the intake manifold.
Because of this, the intake manifold will often have many vacuum outlet ports found on it. Vacuum Accumulator / Vacuum Box Some custom application intake manifoldsor those manifolds equipped with individual throttle bodies, do not have enough room to accumulate sufficient engine vacuum.
This is ancient history to me but I believe the reason for 2 vacuum lines was because Ford used a dual-diaphragm modulator valve that was supposed to help shifts and in turn aid emissions. This used both manifold vacuum and ported vacuum from the carburetor body and did not work too well.
The vacuum lines to the transmission tell the transmission’s vacuum modulator how hard the engine is working. Low vacuum means it’s working hard, because you have the throttle open more, high vacuum indicates the engine is not working hard because the throttle is closed more.