Swirl flap issue on BMW engines...

[e34.535i.sport]

I don't know how much this has been covered here but I do know a few of the e34 guys here were looking into buying an e39 a while back and a few guys already own one so I thought I'd copy over this thread I've just posted on the e39 forum. The 'swirl flap' issue also affects other cars too like some e46's and e60's, and even non-BMW cars that use their engines... Might be of interest to someone here. If you need to know what swirl-flaps are to begin with just google it, seems to have caused much controversey.

My Swirl flap experience (2000 530d auto)
I managed to remove the swirl flaps from the intake manifold and replace them with a nice set of much 'safer' blanking plates I purchased from ebay and I thought I'd sum up my experience in a single thread. The main reason for this is that it took me a great deal of time to research this topic and I had to visit many different sites to find out all I needed to know about swirl flaps (some of which are very informative) and to remove them successfully, so I am going to put it all together here to hopfefully help people in future.

Firstly - 'Do I have swirl flaps?'
We'll this is difficult to find out for sure online. Cars affected are diesel automatics, not manuals. I managed to find a thread somewhere that told me to look/feel under the manifold for a bar going right across... This is good advice if you want to know for sure. If you have a thin metal bar, you have swirl flaps. My 530D had the flaps.

Now - 'What size swirl flaps do I have?'
Well from what I can gather there is no definitive list, but it seems earlier cars like mine have the 22mm flaps, and later cars (possibly 2002 onwards?) have larger 33mm flaps. I took a gamble and bought the 22mm flaps as my car is an early model, and it paid off - I was right. Maybe ring the dealer for more info if your not sure.

'Is it hard to remove swirl flaps myself?'
In my opinion, no. There's not much to it really but I have been working on cars for a few years now as a hobby... Still, I'm no expert and if I can do it, most should be able to tackle this job. My advice however is do your reseach. Here are the three sites I used to advise me. The top being the most useful: Untitled Document http://www.bmwland.co.uk/swirl_flaps...wirl_flaps.pdf Removing the swirl flaps in a diesel engine - 5 Series Forums

Follow the instructions and you can't go too far wrong. It took me and a friend (very useful to have two pairs of eyes and two brains to remember where everything goes!) about 3.5 hours start to finish.

'What effect will the removal have on the car?'
Well the obvious effect is the added security that a flap won't fail and cost you ££££ to fix. The flaps I removed seemed in fairly good condition (126k miles on the car) but I feel much better now they're out. Other than that the car is very much the same and I've had no negative effects. MPG has increased a little recently but I also changed the egr thermostat the week before and also blanked off the egr vacuum hose at the same time so these will have had an effect on this.

And finally 'How much will it cost overall?'
Well for me it cost £36 (for parts) and a sunday morning... I bought six swirl flaps from ebay for £6 each and that was it. Cheap cost for peace of mind that's for sure.

Well I hope that clears up a few issues for people searching for this information in future.

[whiskychaser]

I was half way though reading this and thought, 'hey I know somebody who may be very interested in this'. When I got to the bottom and saw your sig I felt rather silly

What do they actually do?

[mikell]

Neat write up.

For a second there I thought we were going to get a sales pitch for the Turbonator of yore - but then, we didn't get BMW diesels in the US for a long time.

[e34.535i.sport]

Haha !

[e34.535i.sport]

Haha I like it! In terms of what they do, to be honest I'm not too sure! I read something about maximising efficiency under light load but after removing them I've noticed no difference at all so they can't do much