[Closed] Whats a "Swirl Flap"?

It controls the foo foo valve.

BigJohn - Member

It controls the foo foo valve.

Don't you mea the Wah-wah socket?

http://lmgtfy.com/?q=http%3A%2F%2Fwww.swirlflaps.co.uk%2F

🙂

nasty - leads to sludging of the wiffle pits

I thought they were to damp the air flow after SurfMatt's flounce.

Their proper name is tumble flaps, looking at those google results it seems BMW have decided to rename them, because they can. They are inside the inlet manifold and are a valve/flap which directs the airflow to the actual inlet valves, with a profiled runner to introduce tumble/swirl of the airflow, promoting better mixing of the air fuel mixture, and so better combustion.

The more agitated the air going into your engine's cylinders is, the more complete the burn is, and hence it is more efficient and powerful for a given amount of fuel.

Some newer cars have "swirl flaps" in the intake manifold, these are there to introduce more turbulence to the incoming air in order to promote a better burn.

mmmmm not good news i'm afraid ,this is very common on bmw d engines,hopefully it won't have done any serious damage,the good news is you can have the swirl flaps blanked over /removed,it will never happen again and it won't effect your engines performance,
"why are they fitted then?" is a logical question at this point and i can only say it's an e.u emmisions thingybob but your d will get on very well without them.

Thats bad news im afraid. Sounds like the emergency engine management kicked in, due to an engine problem. And if it is indeed a swirlflap failure, the prospect isnt great.

I use to own a 320d touring, and after a few nightmare stories from other owners I had my swirl flaps replaced with blanking plates.

The swirl flaps basically sit at the entrance to the manifold, and rotate back and forth,(not sure of there exact purpose, but believe they are there to help fuel management when idleing. There was no negative impact in the total removal of mine.

Anyhow the flaps have a tendancy on e46 models and earlier, to corrode, break loose, drop into the manifold, and at worst totally wreck your engine cylinders. Which, according to many angry owners reports, results in exactly what you experienced. Ie, no power etc.

Id get it down the dealers/decent independant straight away if you can. It will be easy to see if theres been a swirl flap failure. Literally a 5min job to check.

Good luck!

The garage that removed mine said they had another 4 bmws booked in that week for the same removal process.

Cheers for the replies, it's good to know exactly what they're talking about!

But the plot thickens... it would appear that my car has had the flaps already removed! Weird, anyway, it's still at the menders with the engine all over the floor.

I've just today had the swirl flaps out of my 320cd and PMW blanks put in their place. 320d before 2004 were rife with problems with the screws that secure the flap to the are failing and flap disappearing down the inlet manifold resulting in the the engine going bang. Later models had one piece flaps which cured this

I had the flaps out of my 320d last summer and replaced with screws/epoxy. As I was removing the last one from the manifold, it literally came apart in my hands. Lucky escape 😯

The giggling pin has fallen off the laughing shaft 😯

They are the tonsils of car world aren't they?

Aren't they for increasing EGR? Which reduces harmful emissions. Not like that matters to BMW drivers, that would mean giving a sh*t about someone else 🙂

Get a BMW independent to blank off the EGR, remove the DPF and get it remapped to delete the regen. More power, more mpg and a whole lot less to go wrong...

similar question; is it the same situation with i engines too? I have a 116i and recently the emissions light came on and even after service/MOT it's still there. I happen to drink with the service manager for a large BM dealership and he says "it'll be crappy supermarket fuels you put in it you pikey bastard" (or words to that effect). Basically was told to ignore it as it is there to indicate if you were likely to fail a continental emmissions check.

but I still feel I ought to be worried. should I?

Get a BMW independent to blank off the EGR, remove the DPF and get it remapped to delete the regen. More power, more mpg and a whole lot less to go wrong [b]and more soot and nasty pollutants to mess up the air quality and cause health problems[/b]

FTFY.

So after the best part of 10 days down the garage they say it's the "high pressure diesel pump". At 1500rpm it just gives up and cuts the engine out.

That sounds expensive.

resisted, take your car and cane the absolute pants off it, really rag it. Should help shift the engine scoot etc, gets the cat nice and hot too.
*I accept no liability if ANYTHING bad happens as a direct result of the above*

My Passat is majorly improved by half an hour driving at 100mph 🙂

That sounds expensive.

Is pretty much what I say everytime i'm at the garage!

take your car and cane the absolute pants off it, really rag it. Should help shift the engine scoot etc, gets the cat nice and hot too.

I do a lot of long motorway miles, will that get it hot enough or are we talking "drive it like you stole it" territory to see an improvement?

Get a BMW independent to blank off the EGR, remove the DPF and get it remapped to delete the regen. More power, more mpg and a whole lot less to go wrong and more soot and nasty pollutants to mess up the air quality and cause health problems

FTFY.

Here's the key: 'more mpg' ergo less emissions per mile...

Further, it's the tiny particles which cause the most harm, not the larger sooty ones (although I agree they're not benign); a DPF does not remove the tiny particulate. A diesel running a DPF tends to increase CO2 emissions; don't also ignore the environmental / energy cost in maunfacturing the damn things in the first instance.

HTH

Shouldn't have the issues if you do lots of long motorway miles tbh but a ragging (aka the Italian Tune-up) will always help. Try driving at 80mph in 3rd/4th for 5 or 10 minutes (but don't redline it for that long)

I'm aware of the disadvantages of DPF and EGR. But overall particulates are much reduced with a DPF which coutners a slight increase in consumption I reckon. And what about NOx?

A DPF has an insignificant effect on NOx emissions. More fuel, higher NOx.

aka the Italian Tune-up

LOL, added to vocabulary.

resisted, take your car and cane the absolute pants off it, really rag it. Should help shift the engine scoot etc, gets the cat nice and hot too.
*I accept no liability if ANYTHING bad happens as a direct result of the above*

It doesn't really do much caning tbh, it's only a 1.6 and it weighs about 4 billion tonnes, and it looks like a canal barge. Just trying to figure out why the **** we bought it actually!

A DPF has an insignificant effect on NOx emissions. More fuel, higher NOx.

Yar, I'm talking about EGR - this is a NOx reduction thing.

aka the Italian Tune-up

It's a well known phenomenon and does actually work. Obviously Italian vehicles benefit the most, but it applies to all.

Engines need revving from time to time. Keeps them sweet.

Story time:
I bought a brand new Ducati Monster 696 a few years ago, brand new model, first batch in the country. On picking it up it rode like a dog, snatchy and crude, so I rode it straight back again. 6 miles on the clock. Long story short but it was a fuel injection problem they fixed in an hour or so, and the bike was better. But not perfect. Still hunted on a steady throttle, so I took it back again. They checked it over and declared everything perfect, but the mechanic took it out for a ride to 'put the engine under load'
He came back 1/2hr or so later and said he thought I'd been to gentle running it in, and that coupled with the earlier FI problem had probably left deposits on the sensors. He just said "If it happens again, thrash it. Lots!"
"Ahh" says the manager "the Italian tune up!"

And it worked. That bike ALWAYS felt better after a right good pasting: And I'm talking rev limiter in every gear, up and down the box, slow and fast, for as long as you can get away with it..... 🙂

The EGR valve is the main way of bringing NOx down (unless you have an SCR fitted which little to no passenger cars currently do). Blanking off the EGR valve will have a very good effect on CO2 (and therefore fuel consumption) reduction, but the NOx will go through the roof as they are on a very very steep tradeoff curve.

While your beemers in the garage, can you ask them to fix your indicators? thanks.

A diesel running a DPF tends to increase CO2 emissions; don't also ignore the environmental / energy cost in maunfacturing the damn things in the first instance

A DPF won't increase the C02 per se. During regen it will (to a small or greater extent depending on how good the regen calibration is) but during normal running you should see near zero effect. Also, in removing the DPF, unless you have the whole calibration remapped, then you have just removed a massive lump of backpressure in the exhaust which the engine was calibrated with so your potentially going to upset quite a bit of the cal (can actually lose torque etc). A decent calibrated engine will see very very very minimal performance loss from a DPF.

While your beemers in the garage, can you ask them to fix your indicators? thanks.

Drove a BMW yesterday for the first time ever, weird indicators - I can confirm they do exist, but they don't work like every other car I've ever driven.

How much does EGR affect fuel consumption though, really? It's just replacing some of the air in the cylinder with exhaust, but most of that air you don't need anyway when cruising...?

Speed12 - VW TDIs in the USA have a system for scrubbing NOx - could be similar to SCR.

Will an "italian tune-up" actually help with a sooted up or corroded inlet manifold? Its just air flowing through there and i doubt that would be strong enough to remove the soot.

My car had an engine rebuild for other reasons and i took the opportunity to replace the manifold with swirl flaps for the latest redesigned version. The soot caked on the inside is pretty solid.

(like this (not mine))
[img] [/img]

The EGR valve only recirculates the exhaust gas at partial throttle, which is what gradually clogs up the inlet manifold, so blocking it off or removing it via a remap should help too.

I would say that keeping it clean and tidy inside by a periodic thrashing would help prevent that happening.. but perhaps not fix it. Although on my old Passat the exhaust would've been very hot at the EGR valve cos the pipe was really short, so it might've helped. It was a slow car so got thrashed a lot to make progress, and the EGR was clean as a slightly grubby whistle inside when I removed it because everyone was telling me it'd be gummed up.

But then you are right it only works at partial throttle.. perhaps on my car then the throttle you needed to drive at 70mph was enough to switch off EGR 🙂

They say they've given it a thorough cleaning out at the inlet end so hoping that it'll run a bit sweeter and be a little better on fuel.

xiphon - Member
While your beemers in the garage, can you ask them to fix your indicators? thanks.

In my defence I reckon Audi drivers are the worst.

My vote goes to merc drivers, usually the dimentia setting in C + E class drivers causes them to forget to indicate, likewise the constant re-plastering of lipstick and chatting to gal pals of CLK and SLK drivers distracts them far too easily.

How much does EGR affect fuel consumption though, really? It's just replacing some of the air in the cylinder with exhaust, but most of that air you don't need anyway when cruising...?

Speed12 - VW TDIs in the USA have a system for scrubbing NOx - could be similar to SCR.

Adding EGR lowers the AFR in the cylinder quite dramatically - even with a pretty standard EGRate of around 8-10% your AFR can drop down to 17:1 or so which means although diesels generally are "air rich" you have a lot lot less to play with to get all the fuel burnt. Add to that the combustion temperature lowering effect of adding EGR (which in case anyone was wondering, is the point of it - reduced temperature = reduced NOx) and you get much more unstable combustion which in turn means you need to throw in a wee bit more fuel to ensure you get enough torque. Depending on the combustion bowl design, swirl etc will depend on exactly how much extra you need to put in (i.e. how efficient the combustion system is anyway).

Yeah, the VW system would be SCR. US vehicles are starting to introduce it as the NOx requirements are a lot lower than in Europe. Once Euro 6 comes properly into force you will start to see more SCR on passenger cars in Europe. PSA (Peugeot Citroen) have said that all of their diesel fleet will be equipped with SCR in the coming years. You can also use an LNT (Lean NOx Trap) which is more like a gasoline catalyst, but aren't quite as effective at getting rid of NOx.

Good stuff speed12, always good to talk to someone who knows their stuff 🙂 I read about the VW NOx scrubber, it seemed very complicated.. and people complain about EGR and DPFs!

How does boost pressure affect combustion and swirl? I'm thinking of the VAG 1.6 TDis that presumably use a higher boost pressure to compensate for smaller displacement.

Which reminds me of something.. a while back someone was telling us that their mate who worked for Volvo said that they sacrifice fuel economy a bit to reduce certain particulate emissions of some kind.. any ideas?

Haha, no worries, I'm a diesel calibration engineer by trade so it's te sort of thing I could talk about for hours!

SCR systems are reasonably simple really - it's just like a normal catalyst but needs urea sprayed on it to convert the NOx to NO2. It's a good technology and will actually mean a lot less reliance on EGR valves as they are so effective - which in turn will mean better mpg (CO2) and lower PM. Downside is the control system is quite expensive at the moment but the SCR cat itself is quite cheap as it's a non-precious metal cat (uses Iron or Copper rather than Platinum or Rhodium).

Boost won't affect swirl very much as that is just a function of intake port/cylinder bowl geometry. Combustion wise though, a higher boost simply means more air in the cylinder for a given intake stroke which in a diesel is exactly what you need. It's one of the key parameters we play with to decrease fuel consumption. It has to be calibrated carefully though as higher boost will draw through more EGR and so you could actually end up with higher CO2 and more PM by raising boost. But overall higher is better!

Not too sure about older Volvos, but having just finished the calibration work for the latest C30, S40, V50, V60, S60, S80 and V70 I can tell you they certainly don't now! The cals on those cars are very low PM and with CO2 down to 99-119g/km (very low) and with good NOx as well. It took a bloody lot of work to get there mind!

I did notice that their driv-e or whatever it is eco range looks particularly good (geddit? See what I did there? Particle.. oh well 🙂 ).

Seems to me that most of the wastage in diesels is compressing air that you don't need. So it would make sense to have a small displacement and bigger turbo as seems popular at the moment, so when cruising you can turn off boost and compress less air.

Is anyone working on small 6 or 8 cylinder diesel engines where you can turn off one side by leaving the valves open, like they do on big US petrol pickup engines? Cos I always thought that would be a good idea to reduce wasted compressed air...

[i]I would say that keeping it clean and tidy inside by a periodic thrashing would help prevent that happening.. but perhaps not fix it. [/i]

Hmm. My wife has an Audi TDi and she drives like an old lady. She *never* floors it. When I drive that car it produces masses of black soot. Now I know this is normal for VAG engines but is there actually a sound basis behind ragging it every once in a while. I know knowitall blokes down the pub will say this but what about smart people?

Oh, and swirl flaps. I like it.

When I drive that car it produces masses of black soot

When you granny it, soot deposits build up in the engine. When you thrash it, the deposits get burned up and blown out of the exhaust, which is the smoke you see. It shouldn't do it all the time. And VAG engines do not smoke any more than any other diesel! Take it on a long fast trip and you should be fine at the end. If it's really bad you might have to clean some stuff like the EGR valve out manually, or some sensors might be clogged up so they might need a clean too - but I dunno.

Police officer - Can you tell me why you were thrashing the nuts off your land barge sir?

Diesel Car Driver - Italian Tune Up.

Police Officer - Oh thats fine, nice flaps BTW 😀

ok, ta.

[i]And VAG engines do not smoke any more than any other diesel![/i]

Nah, not all diesels produce smoke. Once my Honda is warm I can cane it with no obvious smoke at all.

My VAG doesn't smoke either.

Sometimes you get a puff from certain cars, this I suspect is a bit of over-fuelling to spool the turbo up as fast as possible. Most produce a very fine blue haze when you floor it which you can't see at all unless it's night and someone's behind you with foglights low down.

Hondas are supposed to be pretty clean tho.

I opened this thread with some trepidation, but find I am bored, not disgusted.

Swirl Flaps, have to like that - are they connected to the Flanges ??

speed12 - Member
Haha, no worries, I'm a diesel calibration engineer by trade so it's te sort of thing I could talk about for hours!

SCR systems are reasonably simple really - it's just like a normal catalyst but needs urea sprayed on it to convert the NOx to NO2.

How do you fill that SCR system up then? 😉

Interesting, you could wee in the tank if you find yourself without 🙂

the reason your diesels don't smoke is because they have a dpf to reduce the smoke. If you whipped that out, you'd see a puff on accelleration like anything else.

My 180,000 mile mondeo is great for leaving a smokescreen. someone a bit too close behind on the motorway? 3rd gear, boot it. Car doesn't actually go any faster (it had all of 88bhp when new. I doubt its got 50 now) but it annoys the guy on your bumper

My diesel doesn't have a DPF, and I do sometimes (but not always) see a puff on acceleration at night. But of course I am not always looking and I also don't have a good view of the exhaust from the driver's seat 🙂 Certainly can't see anything in the rear view in the daytime.

What make of car is VAG??? 🙄
Why not just say VW or Passat, as that's what it is? Or does it make it better by association with an Audi?

VAG is easier to type than "VW/Audi/Skoda/Seat" and they all have the same engines which is what this thread is about 🙂

Yes, I know what it means, but YOU have a VW Passat, so why try and hide the fact.
Actually THIS thread is about BMW's, NOT VAJ's. 😉

Yes, I know what it means, but YOU have a VW Passat, so why try and hide the fact.

If I was trying to hide it I'd lie about it on here and you'd never know 🙂

Actually THIS thread is about BMW's, NOT VAJ's.

I can start a thread about Vaj, I'm away for the weekend so the 3 day ban is worth the laugh. 🙂

At least someone appreciated it!!!

What make of car is VAG???
Why not just say VW or Passat, as that's what it is? Or does it make it better by association with an Audi?

Awesome, inverse snobbery 😀