Hi All. I have a Range Rover 2012 4.4 tdv8 and when I serviced I’dt the o/a air filter was dirty but the n/s like new. This is after 12 months. The O/s one isn’t filthy but you can see it’s doing its job. Any ideas ?

One's for the primary turbo, the other's for the secondary turbo which only kicks in over 2k rpm. The 4.4's pretty lazy / torquey as you know so it spends most of its time ingesting air to just the primary turbo.

Don't forget to give her an Italian tune up once in a while. Deep piling the right pedal and unleashing the second turbo, watching the dials climb is an impressive event. Shifting 2.5 tonnes like that is as amazing as it is entertaining.
. Cheers, Greg
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2011 Vogue SE 4.4 with lots of toys in Stornaway

Thanks so much for your reply. Makes complete sense now. Must dig out my lead boots and put a smile on my face😊👍

Sorry for bumping this thread to life again.

Just changed my air filters too now after 1 year/20k km and got a bit surprised how much more dirty the right hand side was compared to the left one. Reading this thread made me realize the logic behind that.

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Click image to enlarge