i recentlly got a gauge that measures VAC (Vacuum), but i dont really know what vacuum on a car is, can someone help me?
and how much VAC should my car have?
1991 honda accord lx
2007-02-21 14:47:41 · 4 answers · asked by b3nsonx 2 in Cars & Transportation ➔ Maintenance & Repairs
Simply put, vacuum is the opposite of boost. It is the air that is sucked into the engine by the pistons moving down on the intake stroke. A fairly healthy engine will produce 17 -22 inches of vacuum with a steady rpm. Keep in mind to make adjustments in relation to where your elevation. For ever 1000 foot increase above 2000 feet above sea level, your readings will decrease about one inch. Make sure one your engine (f22a) that you connect it directly to the intake manifold vacuum and not the throttle body vacuum. Make sure that you don't leave any hoses disconnected during the test.
2007-02-21 15:40:03 · answer #1 · answered by I THUMB DOWN N00BS 4 · 0⤊ 0⤋
Here is the short version. See the link for the full explanation. 16-18 inches is average for a good engine at idle.
"Manifold vacuum, or engine vacuum in an internal combustion engine is the difference in air pressure between the engine's intake manifold and Earth's atmosphere."
2007-02-21 23:08:34 · answer #2 · answered by monte 6 · 0⤊ 0⤋
Vacuum is produced when you take your foot off the gas. In the 50s and before, vacuum was used to run the windshield wipers.
In the 70s they would run vacuum driven air pressure pumps (for the suspension)
2007-02-21 22:59:01 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Vacuum is created by the piston moving downward in the cylinder. As for what reading you should get from your car, check a shop manual for your make, model and year.
2007-02-22 11:55:29 · answer #4 · answered by ? 4 · 0⤊ 0⤋