Dumping...

[cornish6544]

So I've noticed when I lifted the bonnet and rev'd it by hand that it seems to be dumping from the air filter? :S 

 

I have a blitz dump valve fitted and it seems to make the noise alright but if I put my hand over it then it's not dumping properly any ideas?

[savage bulldogs]

Most d.v springs will only operate above 0.3 bar of positive boost and above. So the noise you here from the air filter is probably turbo stall or "flutter" when stationery as the dump valve won't be able to get enough vacuum or boost to operate fully without the engine being under load (pulling the cars weight along).

It might be worth getting the mapper to check over the fuelling and boost map though . As you've just fitted a new up pipe and that might change the gas flow a bit and you might need the map tweeking a bit

If it's not broke .....upgrade it 😊