Andy K said:
...
Vauxhall one way valves are £10 are are usless and break,
Maybe get one from halfords....
Go to a
pet store, and ask for a one-way valve for your fishes' tank. You'll get two for £2.
cheaper than any of the 'tuning' jokers.
Flows better, too (scientifically tested by blowing throughlmao )
A MUST for high-boost turbos

Just make sure you install it the right-way round (or else you'd be boosting your camcover!)
Seriously, it's better
Ain't the internet wonderful?

:beer: