I remember when I first bought the car, when I turned it off I can hear a pressure exit noise from the engine bay. But I don't seem to hear that anymore. Is that normal?

 

The sound of your intake breathing a sigh of relief? I don't recall hearing it with the stock airbox, but with the cover off or with an aftermarket intake, you should hear it.

 

yeah that! "sigh of relief" ahahah good choice of words. Actually I heard it with a stock intake air box. Right now I have a Stock Intake airbox with the resonator removed + a K&N filter.

 

Hmm, I don't know why the sound would go away unless you've gotten used to it or your engine has lost compression. Any loss in performance?

 

no clue. should I do a compression check? what are normal compression numbers? and whats wrong if my pressure are low?

 

I was getting 240 psi across the board with my old car after the engine rebuild, so I'd expect yours to get the same or higher. The most important thing is to make sure the compression is consistent across all the cylinders.

If it's low, it could be piston rings or valves not seating properly. The way to check is to do a "dry" compression test, then drop some oil in the sparkplug hole and do a "wet" compression test. The compression should go up. If it doesn't, then I believe the rings are shot ... or is it the valves? I haven't done a compression test in years, so I don't remember the specifics

Anyways, I hope somebody else jumps in here and gives you a second opinion. Maybe you should try taking the cover off of the airbox and see if you can hear the noise. Speaking of which, when was the last time you cleaned the air filter?

 

Thanks for the info~!!! I switched out the old filter with the K&N last month =[