My mom has a 2014 gl550 with the 4.7 L twin turbo v-8 and when it goes through its cold start you can hear the turbos spool which I am assuming means that the wastegates are closed (pneumatic)
now is that possible to get a turbo spool when we start up our cars (close EWG)
I have catless downpipes and a custom axleback so I can hear it when in sport + but cold start turbo spool would be nice
(if you listen closely you can hear the distinct turbo spool)