M47 swirl flap removal
Discussion
The OH has an early 2005 E87 120d with the M47 engine. It's done about 100k miles. I'm conscious that the swirl flaps could be a ticking time bomb, so I'm thinking about getting them removed. I have a few questions, though, relating to some info I've found online...
At low engine speeds, these valves are closed which causes air to swirl around the combustion unit and creates a better fuel-to-air ratio.
So there'll be a poorer fuel-to-air ratio at low engine speeds if they've been removed?
An improved fuel-air ratio decreases the emission of pollutants...
So the car might fail an MOT on emissions then?
... and increases the performance and fuel efficiency of your engine.
So it'll lose performance and fuel efficiency?
If they're closed at low engine speeds, and this improves fuel efficiency, does that mean poorer fuel mileage on long A-road/motorway runs at 50-70mph where the engine is usually just under or around 2,000rpm?
I've heard about blanking plates as a replacement. Wouldn't they have the effect of the swirl flaps being permanently closed, so you lose the benefit of them being open at the relevant higher RPMs?
At low engine speeds, these valves are closed which causes air to swirl around the combustion unit and creates a better fuel-to-air ratio.
So there'll be a poorer fuel-to-air ratio at low engine speeds if they've been removed?
An improved fuel-air ratio decreases the emission of pollutants...
So the car might fail an MOT on emissions then?
... and increases the performance and fuel efficiency of your engine.
So it'll lose performance and fuel efficiency?
If they're closed at low engine speeds, and this improves fuel efficiency, does that mean poorer fuel mileage on long A-road/motorway runs at 50-70mph where the engine is usually just under or around 2,000rpm?
I've heard about blanking plates as a replacement. Wouldn't they have the effect of the swirl flaps being permanently closed, so you lose the benefit of them being open at the relevant higher RPMs?
Rover 75 had one (M47R same engine configured for fwd).
Rover, I believe, removed the swirl flaps for the 75 in the factory.
(I believe they can be ingested into the engine writing it off.)
My old 75 never failed an mot on emissions even when I blanked off the egr (which clogged and became a pain)
It also went very well and returned good mpg but can't remember what.
Rover, I believe, removed the swirl flaps for the 75 in the factory.
(I believe they can be ingested into the engine writing it off.)
My old 75 never failed an mot on emissions even when I blanked off the egr (which clogged and became a pain)
It also went very well and returned good mpg but can't remember what.
Oilchange said:
I believe they can be ingested into the engine writing it off.
Yes, that's what I've heard. Either the plastic flaps break and are ingested, or the screws holding the assembly work their way loose and are ingested.Oilchange said:
My old 75 never failed an mot on emissions even when I blanked off the egr (which clogged and became a pain).
The OH's engine light is on which, we're told, is due to a clogged EGR. It was cleaned but in due course the light came on again.The car itself is really solid. She already owned it when we met over 12 years ago and, other than a corroded reluctor ring, it's been faultless.
My missus car is a 2005 120d with the M47 engine, owned for 4 years, 104k when we bought it now on 123k.
I removed the swirl flaps soon after buying it with an ebay delete kit.
It did seem to lose a bit of low down pull below 1750rpm but we soon got used to it and Mrs didn't notice anyway.
It's passed emissions fine in the last three years and mpg is around 40mpg round town and up to 50 on a run.
I removed the swirl flaps soon after buying it with an ebay delete kit.
It did seem to lose a bit of low down pull below 1750rpm but we soon got used to it and Mrs didn't notice anyway.
It's passed emissions fine in the last three years and mpg is around 40mpg round town and up to 50 on a run.
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