Hi Adam. Loved your book, "An Inquiry into the Nature and Causes of the Wealth of Nations". Bound to be a big hit.
Running without a dump valve. Well, if it's only the noise you dislike, try improving the soundproofing under the bonnet, and take out any aftermarket air filters (they make almost no difference to performance anyway) and put the oem one in. Generally people complain that the noise is too quiet: myself, I can't understand why they're proud of their cars farting on the overrun.
Chatter on the other hand is the sound of the turbo coming to a halt, spinning up a bit, coming to a halt again, etc, as the pressure in the intercooler pipework (which is now more than the pressure in the exhaust manifold) works its way back through the turbo impeller. Very bad for throttle reaction once the gearchange has been completed and you want to accelerate again.
This is not good for the turbo, which is not designed to take this sudden, vibrating, set of reversals. Whether it will damage it or not is hard to say. I don't expect it will do it any good, almost certainly shorten its life. It's the sound of an engine in pain, crying out for relief: how anyone can stand it is beyond me. The WRC cars, where the sound was first heard, have huge support crews and budgets and can afford to change turbos several times over an event.
I know of no blanking kit for the 1.8T; as said above most people are trying to make the fart louder. There's no performance advantage in removing the valve, indeed as I've said, quite the reverse. So no demand for it.
I wouldn't do it.
