Agree sounds like a region - first thing I notice is the exhaust sounding rather fruity, then the plummet in mpg - usually cured by a steady motorway run at 60mph or above.
My car’s a 2020 Polo GTI+ with the 2.0 litre EA888 Gen 3b engine and a GPF. In the 3.5 years and 15.5k miles I’ve owned it from new there’s been three active / forced GPF regenerations and there are a few noticeable tell tale signs when it’s happening;
- a louder - almost booming - exhaust note
- a slight hesitancy and when accelerating and engine idle lumpiness
- a hot smell
- engine fan running
- stop start is inactive, so the regen process can continue without interruption
- significant worsening in fuel consumption; around a 30-35% deterioration in mpg. The process uses additional fuel to help raise the temperature in the exhaust so accumulated particulate matter in the GPF can be burned off
When I’m aware my cars performing a GPF regen and I’m getting towards the end of my journey, I’ll extend the journey a few minutes / miles if possible so that the process can complete. If not, it will recommence on the next (and subsequent) ignition cycle(s) until it’s finished. Normally with my car, it takes around 25-30 minutes for an active / forced GPF process to run; after that, everything’s back to normal again.
If you’re doing a high proportion of short journeys on an engine that’s not up to optimum temperature, you’ll experience more forced GPF regenerations than if you’re doing mainly long(er) journeys. On longer journeys on a fully warmed up engine, GPF regenerations will be passive and you’re unlikely to be aware of them happening as the exhaust temperatures will be sufficiently high to neutralise accumulated particulate matter in the GPF.
With my car, the process for helping to keep the GPF clear is use the car’s engine braking when the engine’s up to optimum operating temperature. This was recommended by @monkeyhanger (his wife owned a GPF equipped Polo GTI+). Quote from @monkeyhanger’s post on the Polo forum from a few years ago;
‘Engine braking pulls air through the engine that isn’t used in combustion of fuel ("motoring") and ends up in the exhaust where the oxygen is available to burn off the soot as CO2..
I do this periodically on longer journeys - when at cruising speed, drop a gear to increase the engine rpm’s and then let the car decelerate under its own steam to draw air into the exhaust, accelerate back up to cruising speed and then repeat the process a few times. This is actually the officially recommended process for clearing a blocked GPF that’s quoted in some Seat Leon owners manuals.
