[Mr Rauf]

Hi

Was just wondering how many owners have actually removed the swirl flaps from their e90s as I was thinking about doing mine however it doesnt seem like a major problem with the e90s the way the e46's were.

Regards

[stashtrey]

I'm from the US....what is a swirl flap?

[thaking]

Originally Posted by stashtrey

I'm from the US....what is a swirl flap?

+1

[Dsport]

They are small flaps that open and close in the inlet manifold, they reduce emissions on idle
On the E46 they worked loose and go sucked into the engine causing major damage

[Digitalize]

I've considered it as I'm on 173k, and I want to do Glow Plugs anyway so it's sort of half way there.

[BIFCAIDS]

Originally Posted by Dsport

They are small flaps that open and close in the inlet manifold, they reduce emotions on idle
On the E46 they worked loose and go sucked into the engine causing major damage

You're telling me these cars have emotions?

[stashtrey]

Originally Posted by BIFCAIDS

Your telling me these cars have emotions?

lmao x100

[Dsport]

Originally Posted by BIFCAIDS

You're telling me these cars have emotions?

F@@kin iphone

[silver07335i]

Originally Posted by Dsport

F@@kin iphone

lol...

[acerboo]

painful to sit down once removed

[ukbeemerboy]

Originally Posted by Dsport

They are small flaps that open and close in the inlet manifold, they reduce emissions on idle
On the E46 they worked loose and go sucked into the engine causing major damage

Just to add, they were only an issue on the Diesel engines which is probably why it was never a big thing in the US.

[Dsport]

Originally Posted by acerboo

painful to sit down once removed

we both at it now... Sit down

[oldbilly]

This is taken from another forum and I experienced the same problem with the torque at low revs after I had BLANKED the swirl flaps, the paranoia sets in as soon as read anything about BMW swirl flaps, but this is really about the earlier versions and on the e90 the updated cartridge type flaps have cured the problem with no know failures to date.
Swirl flaps have been developed and are there for a reason removal may contribute to dpf blockage and shorten the dpf life, the swirl and tumble technolgy is not just about bwm most if not all diesels have swirl flaps fitted.


My 56reg (reg Nov 2006) 330d E90 with 100k was de-flapped by PMW 2 weeks ago. It was INSTANTLY noticeable, when I was driving out of their car park, that I'd lost some torque. I requested my old parts and after 2 weeks of driving, I'm going to re-install them. They are the cartridge type and look as good as new except for minor deposits which I'll remove before I put them back. I estimate a 50% reduction in torque at c1000rpm and possibly 25% at 1500rpm. I cannot understand people who say they do not feel any difference. They must never drive at under 1500rpm. Also, my fuel consumption has increased markedly, especially around town, where I estimate it to be c5>8mpg worse, and on the motorway, where I generally cruise at 80>85mph, to be 3>5mpg worse. At 80mph the engine is only turning at 2000rpm, so the flaps will have only just opened fully. My job is developing inlet and exhaust ports, and inlet and exhaust manifolds, and I know exactly what the swirl flaps (or port de-activation units as we call them) are for. At low RPM they close off one port which doubles the airflow through the open port which gives much improved air/fuel mixing at low RPM and thereby gives lower emissions, increased torque, and better fuel economy. This is done by changing the in-cylinder air motion from Tumble (with the flaps open) to Swirl - hence the name. I hope this adequately explains their purpose.

[90MSP]

I was offered this by a local garage but declined and just had them cleaned instead. As you say, not really an issue with the E90 plus the school of thought that BMW put them there for a reason makes me keep them in place.