dime1622

ok im about to buy a new bov, but want to make sure that im making the right decision.

i can make boost, but it seems like im down about 30 hp (butt dyno). at 1.2-1.25 bar, i get a loud rush of air from under the hood (cant listen under the hood as the only time you can make boost like that is under load, and i can just hop on a dyno for free to use its load. anyway, please reassure me that my diagnosis is correct.

i was told to pull the vacuum hose to see if the pressure bleeds down to see if it was the bov, but i have no pressure gauge, and did not really even understand the instructions anyway. if i take it off the car can i tell if its ok or not? like opening it up? and how?

thanks!

adrial

Pull it off the car and have a look at it...

do you have a digital camera?

dime1622

i wish i did, if i pull it off the car, what am i looking for? (not identification of the bov itself, but what about it am i looking for?)

Asarus

You look for a bad BOV as shown on these pictures

Asarus

A good one shoud not have this leak down...

Here is a brand new 993tt model (made of metal) :

dmoffitt

could also be a cracked boost hose (look UNDER the hoses, it's typical that they crack @ the hardest to see places lol)

Waterguy

I second the vote for a loose or cracked intercooler hose. My identical symptoms were caused by a loose hose at the turbo outlet (hardest to see, hardest to get to, highest heat.) Remove and check all four rubber turbo-intercooler-manifold hoses.

To check the BOV, suck or blow on the small inlet port. If air leaks in or out, the valve is bad and needs to be replaced. You may want to do this in the privacy of your own garage!

dime1622

suck or blow on the top nipple where the tiny vacuum hose attaches to?