Turning low load without boost

How do you guys feel about disconnecting a boost pipe to tune low load areas ?

Heard some tuners doing it.

Could there mechanical problems? Turbo over revving or such?

Regards Sigve

It won't accurately reflect the pressure ratio across the engine under normal running conditions but it might be close enough. I would prefer to run very soft wastegate spring(s), remove them completely or disconnect the linkage of internal gate if you want to progress the tune very slowly/carefully. Even doing that if you intend to run a higher gate spring will likely result in slightly richer running on an intake MAP only SD tune under normal operation but means you don't have to fight trying to hold load points when tuning.

Definitely not advisable. You'll end up with a totally unrealistic map as the turbo and the back pressure in the exhaust it creates, have a large effect on the VE of the engine. Not to mention there is the potential to overspeed the turbo.