My friend installed a Denzo Blow off valve and whenever I start the car it's really loud, like sucking sounds.. I can't explain how Loud but is Loud. The car normally gets 2-3 rpms when i start it, could it be loose or is that normal?

 

2-3k rpm is normal on start up. The BOV shouldnt have anything to do with your car being loud when you start it because all it does is release the boost pressure.

 

FDs have the accelerated warm up system (AWS) that kicks the rpm to 3k when the engine is cold upon startup. So, it's pretty loud. You can defeat the AWS by starting in gear or just tapping the gas a little.

If your car is still loud and there is a sucking sound, check all the intake hoses and airbox. Maybe one of them isn't fitting perfectly and is leaking.

 

It sounds normal to me. When I had my stock BOV vented before I disabled the AWS system, there would be a huge surge of air rushing out of it, I would call it more of a blowing sound than a sucking one...almost like a hiss.