[Exxie]

Hi all,

I recently made a number of changes to my 2007 E92 330d (M57N2), including blanking the swirl flaps when I had the manifold off for a clean. After some reading, I've now decided to reinstall them in the hope that it will help my primary problem - very stinky (but now smoke-free) exhaust when idling.

Below is a photo of the swirl flaps removed from my manifold (I'll give them a good clean before re-installing). Can someone please verify that they are the newer kind, not prone to breaking off and being ingested? The blanks I purchased were 33mm in diameter.



Secondly, I didn't have a torque wrench when I reinstalled the manifold so I just went by feel, but I would like to torque it up properly this time. Does anyone know the correct torque for the 7(?) large nuts and 12 smaller bolts?

As always, big thanks in advance for any help!

[Ajs_435d]

Yes they look like newer type, 32mm check that orange rubber ain't coming off mine were leaking little bit of boost.

[Exxie]

Originally Posted by ajs_335d

Yes they look like newer type, 32mm check that orange rubber ain't coming off mine were leaking little bit of boost.

Thanks! The rubber gaskets are a bit worn and there was oil leaking from around them. I've read of people sealing them with silicone sealant, is this the same stuff used for bathrooms, etc?

[oldbilly]

Originally Posted by Exxie

Thanks! The rubber gaskets are a bit worn and there was oil leaking from around them. I've read of people sealing them with silicone sealant, is this the same stuff used for bathrooms, etc?

I inspected and re-sealed mine using a good automotive silicone sealant and I've no leaks since.

[tmarshall57]

Those are the new type. Strongly recommend sealing them when you replace. Tiger seal worked for me and recommended by others.

[Exxie]

Thanks for the recommendations, will definitely look into using some sort of automotive sealant.

Any advice on the torque for the manifold bolts or where I might find the specs?

[jimbo666]

Did you find any performance drop with the blanks fitted?

[mistryn]

Can you get the orange rubber seals separately from BMW?

How hard/easy is it to remove the manifold as I want to take mine off clean as one one cylinder is leaking oil

[Ajs_435d]

I'm going to post a thread.

But my 335d was tuned to stage 2,it was originally a smidge under 350bhp/525lb ft, I cleaned out intake manifold and inlet valves though difficult to clean, also fitted swirl flap blanks.

Upon taking the swirl flaps they has some carbon build up but orange sealing rubber was failing o ring were ok but oil on them, I reinstalled all with swirl flaps and car jumped 20 odd bhp and similar torque to a final figure of 371/557 on the 'same' dyno.

I have noticed no drop in performance.
Imo the swirl flap removal didn't contribute too much to perform it was more there was a small boost like around the rings.

[Exxie]

Originally Posted by jimbo666

Did you find any performance drop with the blanks fitted?

Not sure as I changed a number of things together, but the idea behind them makes sense. At maximum load (like when on a dyno), they are fully open so effectively do nothing, however if they are leaking, obviously you will lose boost.

At low loads (like when idling), closing one of the ports should help the air and fuel mix and lead to a more complete combustion. Hopefully I'll notice a bump in low end torque, but really the main issue I'm trying to resolve is the smell.

I'll let you guys know my findings. Nobody has any idea on those bolt torques???

[jimbo666]

Thanks for that. I'm looking to blank mine. In the past, I've just done them up by feel. I've had the mani off 3 times now and have had no issues.

[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.
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.

[mistryn]

Originally Posted by ajs_335d

I'm going to post a thread.

But my 335d was tuned to stage 2,it was originally a smidge under 350bhp/525lb ft, I cleaned out intake manifold and inlet valves though difficult to clean, also fitted swirl flap blanks.

Upon taking the swirl flaps they has some carbon build up but orange sealing rubber was failing o ring were ok but oil on them, I reinstalled all with swirl flaps and car jumped 20 odd bhp and similar torque to a final figure of 371/557 on the 'same' dyno.

I have noticed no drop in performance.
Imo the swirl flap removal didn't contribute too much to perform it was more there was a small boost like around the rings.

do you have any step by step instructions/pics as i plan on removing mine to have a lool/clean?

[Ajs_435d]

Hi i dont sorry

Its pretty straight forward think there is a guide on here.

Like i say to the above, i noticed no reduction in torque or power dyno confirmed this is for a 335d though

[mistryn]

I will have a lok for th guide - is there one specfic for the 335d? I have seen the one for the 530d which I presume is similar?

I dont plan on blanking my swirl flaps but is there a check to see if they are working well?

I just want to take the inlet mani off, clean (any tips on cleaning the inside of the manifold?) and refit with new seals

[Exxie]

Originally Posted by mistryn

I just want to take the inlet mani off, clean (any tips on cleaning the inside of the manifold?) and refit with new seals

It's fairly straightforward to take it off, just make a note of which bolts go where. Make sure you have the new gaskets before you start and take care when you lift it off as if any of the gaskets have come free from their grooves, they may drop into the cylinder.

I cleaned mine with degreaser, bottle brushes and a pressure washer and left it for a couple of days hanging to dry. You don't want any water in it when you refit. If it's full of oil, there's a good chance your intercooler is too (mine was horrendous), so you may want to rip it out and have at it with degreaser while you're at it.

I'll be refitting my swirl flaps this weekend and will report my findings.

[Exxie]

Ok, so I've just completed the job, but for some reason the flaps aren't closing (I could only check at idle) so it obviously has made no difference. Should the flaps close when idling? I would expect so...

If so, what could be the cause of my flaps staying open? The vacuum pipe connects to a little box with a number of connections and what appears to be another vacuum pipe, could this part be faulty or does it start further down?

[oldbilly]

have you made the electrical connection properly on the vac sensor? I tested mine by locating the flap rod under the manifold with my fingers and get someone to give the engine a rev, you should feel the rod move.

[Exxie]

Originally Posted by oldbilly

have you made the electrical connection properly on the vac sensor? I tested mine by locating the flap rod under the manifold with my fingers and get someone to give the engine a rev, you should feel the rod move.

Which electrical connection is this? I can see the front of the rod from the front of the engine just above the EGR cooler and it is fully open at idle. I haven't got anyone to rev it for me but will do in the morning (I'm in Australia), but I would have expected it to be fully closed at idle if it was working correctly.

[oldbilly]

Originally Posted by Exxie

Which electrical connection is this? I can see the front of the rod from the front of the engine just above the EGR cooler and it is fully open at idle. I haven't got anyone to rev it for me but will do in the morning (I'm in Australia), but I would have expected it to be fully closed at idle if it was working correctly.

yes the flaps should be closed at idle, check the vac pipe connection or if its been pinched somewhere.

[Exxie]

Update: the flaps are closing! I believe it was disconnecting and reconnecting the electrical plug on top of the manifold that did it. Strangely, they didn't initially close at idle; only when revved. After messing about for a while, they decided to close and seem to be working properly now.

There is certainly a little more pull down low. I wouldn't say there's dramatically more torque, but I think it is delivered more smoothly making for a more satisfying feel.

Unfortunately, the smell of the exhaust has not improved. I had been using Millers additive prior to the last few tanks but wanted to see the effect of reinstalling the swirl flaps. I think I'll continue using Millers again as I believe the smell got slightly worse after I stopped. Any opinions on this or other fuel additives? I have read good things about dipetane and am considering giving it a go. The diesel quality here in Australia is pretty poor.

One last thing, when torquing up the smaller manifold bolts (I found a DIY that stated 15nm), I actually snapped two of them. The snapped bolts are not next to each other, but they are on consecutive cylinders. Is this likely to cause any major problems? I don't appear to be losing too much boost and it would be a lot of work to rectify this so I'd rather leave it be...

[335DEE]

Originally Posted by mistryn

I will have a lok for th guide - is there one specfic for the 335d? I have seen the one for the 530d which I presume is similar?

I dont plan on blanking my swirl flaps but is there a check to see if they are working well?

I just want to take the inlet mani off, clean (any tips on cleaning the inside of the manifold?) and refit with new seals

Blank them off mate .. could be the cause of poor performance as they are a weak point for boost leaks.
Mine were blanked off last year .. you won't notice any difference .. especially the set up you have !