Yesterday whilst I had 5 mins spare I fitted my replacement diverter valve as the car when mobile had been showing that the oem dv wasn't holding boost any longer.

The one I've got came with the usual bits to be able to increase the spring load to run at higher boost as I'm lead to believe.

All went fine fitting and all in place as should be. Started the car to check everything was connected and no leaks and was fine. Let the car run for a few mins then gave a brief few revs to check if was doing as it should and to my surprise rather than the normal woosh you get when the car is fitted with a cai I had a little flutter from the cai. I tried a couple more times and every time I let off the throttle it would flutter rather than woosh. Now I love this noise and think its one of the nicest noises turbos make but I wasn't sure why it would now be doing that when all I've changed is the recirc valve??

After leaving it running for a few more mins on tickover I did the same again and it fluttered once more and then reverted to the usual woosh on let off.

Is this normal and why would it have done this?

Would the flutter be a safe thing to have or is it a completely bad thing. It was only very mild until it stopped.

So main things are, is this normal and what could have caused this to happen?

Thanks I'm advance guys

Could be that the dump valve may be leaking slightly internally, what valve have you bought?, do you have a boost gauge in the car to see what is happening at that time?.

Could be that the dump valve may be leaking slightly internally, what valve have you bought?, do you have a boost gauge in the car to see what is happening at that time?.

I bought one off of a friend that had one spare from when he bought a load a couple of months ago. Granted it's not forge but I think it's specR or something similar.

I have just been out to it again and there was no sign at all of flutter today, purely the woosh on lift off.

No I haven't got a boost gauge as of yet, unsure of which one to go for and where to mount it when I do decide on one at present.

Granted the flutter sounded good lol but don't want to cause damage to anything.

That's the spring bedding in. The flutter is where it's too strong for your boost levels and not quite opening so it kind of vibrates causing the flutter. Once the springs bedded and been compressed a bit you'll get the normal noise as it's dumps fully

That's the spring bedding in. The flutter is where it's too strong for your boost levels and not quite opening so it kind of vibrates causing the flutter. Once the springs bedded and been compressed a bit you'll get the normal noise as it's dumps fully

Ah I see, I think that's what's happened then. Sounded great with the flutter in fairness but if it means it's now working properly that's the best thing.

Thanks for the response

You will get flutter from time to time when it dumps just at the threshold of boost but it's hard to nail it lol