[Joeaksa]

Clowd,

It helps to have some background with turbo's to understand why they work it this way.

Turbo lag is something that the earlier systems had, where the turbo would spin down a bit inbetween shifts. Lower RPM means lower boost and you want all the boost you can get for more power. After shifting to the next higher gear you would then at times have a slight wait for the turbo compressor to spool up and be able to provide boost.

Enter the pop-off valve. It opens when a pre-set limit is reached and dumps excess pressure out of the system, saving the airbox, pistons, rods etc from overboost and damage. It ALSO keeps the turbo spinning at a higher RPM which then means that its ready to provide boost faster with each shift.

You are correct that you are dumping boost pressure overboard when it hits the max limit pressure but aside from protecting the engine you are keeping the turbocharger ready at a faster speed for the next gear, which means that the boost (read power!) comes on faster.

Hope this helps!

JoeA