[whackernews]

The only thing I can really think of is a turbo Anti Lag System that you can get in top-end consumer cars like Mercedes AMGs. It’s that popping you hear when coming off the throttle, you’ll also hear it in rally cars. The funny thing is, the same popping can happen with any car if the timing is off so you sometimes get kids driving around with misfiring engines cause it “sounds cool” even though their car might not even have a turbo fan! It’s one of those things that if they were actually passionate about these machines they’d know they look like idiots, but they’re not so they do.

[marklubi]

The popping sounds from a turbo car is from the wastegate (whistling sound for a blow off value) when the system is releasing pressure from the turbo that was built up. It prevents over compression that would damage the engine.

[whackernews]

I’m not talking about a dump valve, I’m talking about an ALS as I’ve mentioned. This is where the engine timing is delayed which results in some combustion to happen in the exhaust (hence literal pops). This is used to keep the turbo spooled by MAINTAINING pressure across the system. It’s a performance system.

If your dump valve is popping I think there’s something wrong!

https://en.wikipedia.org/wiki/Antilag_system