I had egr delete fitted on saturday and today was real first time i have driven it since. Did 28 miles to work and just about got home when i started to hear a hiss noise. Definately not turbo sounds more like boost leak, checked the one from turbo thats fine, checked one at bottom of intercooler and thats fine, checked top section and all seems fine.

So basically the only difference on the system is a 90degree silicone bend to egr delete, what are the chances that this is coming slightly loose under boost or that last option there being a hole in the intercooler?

Check for any oil around the 90 degree bend, this would indicate a boost leak.

Havent seen any oil since had delete done. I cant believe intercooler could have sprung a leak. How often does it happen

Do you still have the standard 90 degree elbow? Mine kept blowing off the egr delete, so could be a small leak coming from there?

I got standard one at top of intercooler then the plastic one, i cut off the collar on the top end of the plastic pipe to fit a silicone bend. I am hoping it is like you say and jusy that pipe leaking slightly. Just dont know why it got all way to work fine and it was only near home it started doing it.

The egr delete pipe would have got hot on your drive to work and contracted as it cooled down. May contribute to a boost leak?

Thats what i am thinking, just wish i could pin point it while driving lol.

I am going to pick up new custom pipe tomorrow will see how it sounds once that is fitted.