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Ocallen

Swirl flaps ?

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Someone asked me the other day if I’d had the swirl flaps removed from my engine and I said no. I’ve seen posts where guys talk about this but they are all relating to diesel engined cars. 

Pleading ignorance, does my petrol 523i have a potential problem here or am I worrying unnecessarily?

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28 minutes ago, Ocallen said:

Someone asked me the other day if I’d had the swirl flaps removed from my engine and I said no. I’ve seen posts where guys talk about this but they are all relating to diesel engined cars. 

Pleading ignorance, does my petrol 523i have a potential problem here or am I worrying unnecessarily?

 

Nope; dirty oil burners only ;) 

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39 minutes ago, Ray112 said:

And only ones with automatic transmission.

 

Ah; never knew that!

Any specific reasoning?

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41 minutes ago, d_a_n1979 said:

 

Ah; never knew that!

Any specific reasoning?

Not sure pal, what I have heard is, that swirl flaps slightly improve low down power, something to do with air turbulence and better combustion, how much of that is true I'm not sure. I deleted them on mine week later I bought the car, two flaps were snapped and holding on a last mm of shaft end not to be sucked into combustion chamber, so quite lucky it didn't happen.

Haven't noticed any running issues or reduced power, smoke opacity at MOT been 0.19 last year and 0.08 this year, so that car is running very clean. 

 

Why on E39 era BMW decided to have them only on automatic transmission cars, is good question, because later years they are using them on every diesel engine.

Edited by Ray112

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12 minutes ago, Ray112 said:

Not sure pal, what I have heard is, that swirl flaps slightly improve low down power, something to do with air turbulence and better combustion, how much of that is true I'm not sure. I deleted them on mine week later I bought the car, two flaps were snapped and holding on a last mm of shaft end not to be sucked into combustion chamber, so quite lucky it didn't happen.

Haven't noticed any running issues or reduced power, smoke opacity at MOT been 0.19 last year and 0.08 this year, so that car is running very clean. 

 

Why on E39 era BMW decided to have them only on automatic transmission cars, is good question, because later years they are using them on every diesel engine.

 

Yeah; they were on my previous E65 730D Sport; had them removed when I had the engine fully serviced by @Mashed Potatoes (although he doesn't come on here any more as far as I can see)

 

They were all intact; but not in good working order (or something like that), so whipped out & blanked off

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On the time swirl flaps were introduced versions with auto gearbox needed them to meet the required exhaust regulations. Manuals just passed without so they left them without. When swirl flaps are closed the shorter straight intake duct is closed and all air is routed to swirl port. Like the name says it will cause a swirl inside the combustion chamber which makes the burning more efficient on low load (fuel atoms meet oxygen atoms more easily).  Also remember the shape of diesel piston and where fuel is sprayed.

 

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Thanks guys. Nothing for me to worry about and useful information for others.

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My 525d manual definitely did not have swirl flaps.

 

My understanding is that the pre-facelift 530d's with the 184bhp engine also did not have the swirl flaps. 

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15 hours ago, E39mad said:

My 525d manual definitely did not have swirl flaps.

 

My understanding is that the pre-facelift 530d's with the 184bhp engine also did not have the swirl flaps. 

 

Swirl flaps only on 3/2000-> models with auto gearbox.

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If you are looking for a complicated innovative device in a similar vein to worry about with the e39 petrol engines then it would be the DISA.  Plenty of info on this and other forums.  Though i have not seen an actual post where one did destroy someone's engine.

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Had these things on our last car, a Mondeo 2.0 petrol auto. So well know for being ingested that there were no repair kits available from Ford at the time so I had to suffer the cost of a complete inlet manifold with 'modified' swirl flaps/shaft. Fortunately (unusual for me !) the garage took pity on me & charged me 'trade' on the component.

Later found out that many people simply removed the flaps (doh) but then I couldn't have done that myself anyway.

 

'Oh the joys of motoring :(

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