Civic EG

i completly understand boost and the concept and everything and what not

however i have one question concerning my boost guage...

i know the top part (psi) is how much boost im running in pounds per square inch but when im idleing and my gauge is reading 10 to 20 vaccumme whats that mean? does that mean there is no boost or?? idk thats only part of boost i dont understand lol and the only part i have not been able to find through research

you are correct. a normal NA engine produces vacuum. When the cylinder moves down and sucks in air, it creates a vacuum. So when your boosted engine is idling it will produce a vacuum. Then as revs increase and the turbo spools the vacuum will go from -20 and go toward 0. As the turbo keeps spooling the psi will keep building. after 0 psi there is more pressure being forced into your intake than there is in the atmosphere = no longer a vacuum.

ohhhhh i get it! so basically i am correct...when the gauge is at -20 the vaccume is greater than the force the supercharger (in my case) is producing, as i increase the rpm's the boost becomes greater than the vaccumme making the needle go to the + psi side thanks alot i appreciate the help.

the beauty of boosting. Miss bossting