Right, so I acquired a Forge BOV from someone breaking their car. There were no issues with it and got it fairly cheap. When I fitted it and tried it out with the bonnet up made a lovely noise and could hear it functioning as it should be. However, when I have been driving under a lot of boost, towards peak it makes the awful squeaking noise when dumping that I have heard about. I only thought that I needed a stiffer spring as it is not a standard t-jet. It has been remapped and therefore runs more boost. (Around 20-21 psi according to the boost gauge).

So, I messaged forge about this thinking I would only need a replacement stiffer spring and this would be problem solved. But, instead they told me that it sounded like I had the 1st version of the valve and they offer a conversion kit which includes a different type of valve for £72 this would eliminate the metallic sound.

Very curious to see if anybody else has experienced this and what their outcomes were to this.

Regards,
Daniel