Swirl Flaps delete or not N57 30d

[H4MP]

So as some of you know I'm having an engine rebuild, due spun bearings most likely caused by oil starvation although this engine does have such issues at higher miles. Now the indie has recommended I do a swirl flap delete, although he did say he's never seen a failure on an N57. I keep reading that there is reduction in mpg and reduced torque are lower down in rev range. What would you guys recommend?

[X5Sport]

Swirl flaps on the N57 engine are a different beast to those fitted to most M57 engines. They are attached by a continuous rod assembly rather than the M57 system that allowed individual flaps to fall into the engine thus making it much harder unless a rod breaks, and even then you’d be pretty unlucky. I did them on my wife’s E46 M57, and noticed that under power it smokes more. Might be coincidence however. Note to other readers, the E53 X5 was not fitted with swirl flaps despite what you might read on line.

I’ve also not heard of an N57 failure, or at least, none have been reported on here.

Personal choice. As they have the engine apart, ask them to inspect (and clean) your intake manifold assembly to see what state things are in. If you’re that concerned then possibly get a new intake manifold fitted as the flaps are built into it.

[H4MP]

I was reluctant to do it but the mechanic said last thing you want is a failure due to the Flaps although highly unlikely, don't really want a reduction in mpg and lowdown torque. My current X5 the SD or 35d version still has swirl Flaps it's a 2009, I never bothered blanking them.

[Leslie]

Note to other readers, the E53 X5 was not fitted with swirl flaps despite what you might read on line.

Neither was the early manual 330d e46 like I had but the auto was for some reason

I think id get them inspected as said above and if they are in good condition after what I'm guessing is high miles then they should be fine.

[H4MP]

Mechanic did inspect them and said they seem fine and are in decent condition.

[Leslie]

Id leave them in if it was me

[X5Sport]

[Neither was the early manual 330d e46 like I had but the auto was for some reason

The 2005 330d had those spawn of evil! I think they were needed later to pass EU4 emissions, and for the convertible at least, it could not pass without them (and was manual only for the same reason).