Disa removal / delete?

[bcredliner]

As mentioned several times, with the DISA valve flap removed engine performance is compromised since you lose low end torque and high end horsepower. Losing torque and horsepower will also negatively impact mileage. Since you have to remove it to remove the flap, I would rebuild or replace it, no exception. When the flap is rattling it should be addressed ASAP. Currently it is a small low cost problem but could become a huge cost issue at any time. It is likely the reason you didn't notice a lose of performance when you removed the flap on your diesel was because it may not have been sealing for some time. IMO you should fix it right rather do a shade tree work around.

[wpoll]

Originally Posted by bcredliner

It is likely the reason you didn't notice a lose of performance when you removed the flap on your diesel was because it may not have been sealing for some time.

While DISA valves and swirl flaps look similar, they work rather differently. The swirl flaps (multiple) in the diesels do not contribute much to power gain - they are more about engine efficiency. Almost no one has ever noticed the removal of the swirl flaps in the BMW diesels, even if removed when working properly.

But while they work differently, they fail in a similar way, with similar results!

Lots of info. here: -

BMW diesel engine SWIRL FLAPS - all you ever need to know

It's an interesting read, even if you don't own a diesel.

And since I've gone and hi-jacked Shel's thread, I'll mention that Shel is dealing with the DISA flap on a 3.0i (or at least Shel's previous questions have been about a 3.0i so I'm assuming this question relates to the same car...).