I just went around on this on my wife’s turbo gas Peugeot, and I’ve had a turbo diesel Peugeot. A waste gate is an integral part of turbocharging an engine. I’ll admit its more important on a gas than on a diesel. The max boost is designed to happen at medium power and the waste gate dumps anything over that around the exhaust fan. I’ve had the waste gate actuator fail on both the gas and diesel with different results. The gas goes over-boost very quickly and the ignition cutoff interrupts the show and the car in pretty much undrivable that way. The diesel on the other hand had a barely noticeable increase in power. I don’t know why the difference, whether the diesel was under boosted, or didn’t care, or was loosing intake pressure cause of the failure, or what. All I know is that the un-waste gated turbo gas could have chased down a 500e before the boost got cut off.


BTW my turbos have a screw adjust for max boost.