Originally Posted by ///Matt
You should plug them things back in.
The Diverter valves are calibrated to open when there is a specific pressure difference (I beleive .3 bar) between the out let side (which you disconnected) and the manifold pressure side (the small vacuum hose attached to the other end of the diverter.
It's designed to release pressure from the boosted side back into the intake side of the turbos, obviously.
What this does is prevent boost from backing up against the compressor side of the turbo, and causing the impeller to drag. That would cause extra wear (and HEAT) to the turbos. Also, the release of the air back into the intake side performs an opposite function. When the diverter valve dumps back into the the intake side, the extra air supply actually allows the turbos to spin more freely, again saving wear and heat to them snails.
The problem with what you've done is that these diverter valves are NOT properly calibrated for you've done here. As I said, they are designed to open at a specific pressure DIFERRENCE between one side and the other (of each valve). Now you've allowed the dump side to see a constant atmospheric pressure, not the varying intake side pressures.
You could be blowing off too late, allowing backpressure to hit the turbos, and you are definitely not giving the turbos the dump-assist they are designed for.
NOT TO MENTION, you shouldn't be sticking any homeade plugs in a position where they can fall off into your VERY VERY VERY expensive turbocharger.
Unless i'm not understanding correctly what he did, you won't have to worry about anything that you listed there because the diverter valves are still doing the same job that they have been doing except they are just venting to the atmosphere instead of placing that same air back into the intake plumbing. Turbo's don't need that extra air to function, when that air is vented the turbo's are still spinning without any interference. Basically, if you like the sound go for it because it won't hurt anything.