Differences??? how about invalidating the warranty for a start.
Don't need one its a VGT (Variable Geometry) Turbo which alters the pitch of the fins on the turbine to generate what boost is required at x RPM. This negates the purpose of a blow off valve as it will just alter pitch to generate next to no boost and not stall when you close the throttle. They still have a waste gate to expose of 'excess boost pressure'
Erm, no.... variable geometry turbo's do not have a wastegate- the actuator operates on the fins to manage the maximum turbine speed, and even now are only fitted to Fiat's diesel range- none of the petrol T-Jets use them, not even the Bravo 150.
The T-Jets use the common actuator/ wastegate combo, controlled via a solenoid valve. They have a built-in recirculating "dump" valve that runs off the inlet piping to the throttle body and sends the charge air back into the compressor inlet when opened, and is controlled by the ECU. A recirculating valve generates very little noise compared to the aftermarket atmospheric varieties.
cool I stand corrected . Does that mean getting a 'atmospheric' dump valve fitted could actually make the turbo spool up slower as the charged air is getting lost and not shoved back through the intake to spool the turbo up again?. :chin: