Alright guys. I know this topic has been done to death and I've tried the search function but nothing gives me the simple answer I need.
I'm hearing a slight whistle when applying the throttle - had the sound when I first got the car in April, changed the DV in August and its still there so I am fairly confident this is normal, just need some reassurance.
The whistle is quiet and can only really be heard when the radio is off.
Cheers.
Gaz
When I changed from a split B revision ages ago it was whistling, particularly at partial throttle.
I then changed to a D and it disappeared for around a month and came back again. I didn't rate the D valve for this reason.
In the end I replaced it with a G valve and took the decision to relocate my diverter valve to the front of the engine which is the same as the KO4 setup.
I have had 0 problems since doing this and there is no whistle at all. The only sound I get when driving hard and coming off boost is a whoosh where the excess charged air is recirculated into the air intake which I actually like
.
Access to the valve is awkward but its doable under home ramps or jack stands but if your keeping the car it might be worth considering relocating the DV.