Hi all im new to the forum and new to owning a 05 cobalt ss s/c my question is the boost gauge reads up to 20 psi and 30 vacuum now is it normal for the needle to move into the vacuum zone a lot when im not accelerating? and my second question is im not sure how the car should sound in idle the engine sounds fine but i get a slight grumble from where the s/c is, is this normal? the car has 51,000 miles and the old owner didnt beat on the car at all. thanks for any info any of u can send my way.

 

lol ya def. a nube to the balt world but thats ok everyone was at some point... yes engines create vacume on their own when the blower is not working or your foot is out of it the motor will run vacume when you hit the throttle the blower will create boost in your intake... do some research on how blowers work you will understand. oh ya and a little advice if its your daily driver watch the boost guage as your driving... the more you keep it out of boost the better mpg you will get ... idk about that noise unless i hear it sorry good luck with your modding and congrats on the new toy you will love it

 

so i took a soundclip of the engine during idle u can hear the lifters i believe. what i wanna know is whats that other sound coming from the s/c its kinda like a slight grinding. also my boost gauge sits at around 20 vac when im not gasing the car is this norm.

http://www.youtube.com/watch?v=7xW3vj4debU