[Rukka]

So I looked at getting the LH exhaust open all the time with the hope it might sound a bit beefier. On REALOEM it showed a part for use with the MPE which is called a "dummy flap actuator" - in effect, a blanking plug for when you disconnect the exhaust valve.

They were on back order - part number 18302411427 - and cost about £18.

So back in October I ordered one and finally set about doing the job yesterday.

Here are a few snaps of the part and the process to fit it.

I noticed it had a little sticky out bit that looked like it would clip into a hole - more on that later.



First job is to get the flap open. I started the car from cold then after about 5 mins flicked it into Sport+ and blipped the throttle (you can hear the flap open when you do this)


Turn off the ignition and now the flap will stay open.
Next job is to lie on your back and disconnect the servo cable. A small bit of plastic needs to be squeezed in and it come out easily. If you find yourself pulling at it, you haven't released it properly.



Now with the cable disconnected, push the dummy flap actuator into the cable end and I was looking for somewhere to clip it up (using the little fitting on the dummy)

No hole was evident in the immediate area; well, where the cable would reach to anyway so I looked upwards and spotted a piece of plastic covering that stood away from the boot floor. Trusty Dewalt to the rescue and a 6mm hole drilled in the plastic.



And finally, clip it all up neatly out of the way




First Impressions

It certainly sounds better from behind and it's nice to see smoke (steam) coming out of both pipes equally.

Driving it, it *does* sound a little bit deeper in tone but certainly not night and day.

Testing it in the works multi-storey this morning, it did still go louder when in Sport mode so not sure what else is happening as it looks like it's not just the flap controlling the sound.

Anyway, for those thinking about such mods, is it worth it? Well, I would say that for the look of getting both pipes open and equal steam coming out - yes. For additional sound, I would say not.

I also noticed the car took longer to warm up this morning. I'll double check this later to confirm... Update - it takes no longer to warm up than normal.

Rukka

[black stig]

What a nice little mod.

Straight on to my "to do" list.

[Kal101]

Good work dude

Not got a x40 myself but always appreciate it when people put up an easily DIY mod to help others out.

[creepy coupe]

So could you have pulled the original plug out slightly to disconnect the pins?

[Rukka]

Originally Posted by creepy coupe

So could you have pulled the original plug out slightly to disconnect the pins?

I guess so. The dummy plug does have some electronics in it and the connecting pins though (probably just a resistor or two)

Having the cable disconnected won't throw an error light but I believe it stores a code for it.

I wasn't sure if it did something else too - altering any engine parameters so fitting the dummy for £18 just made any niggles go away.

[creepy coupe]

Originally Posted by Rukka

I guess so. The dummy plug does have some electronics in it and the connecting pins though (probably just a resistor or two)

Having the cable disconnected won't throw an error light but I believe it stores a code for it.

I wasn't sure if it did something else too - altering any engine parameters so fitting the dummy for £18 just made any niggles go away.

Ah that makes a difference. The pin(s) most likely prevent a dash warnings.

[Grant_7]

Thanks for posting the DIY Rukka.

I'd say there are 2 stages of x40i exhaust mod.

Stage 1: Do Rukka's mod. Get your hands dirty. Get steam out both pipes (always good ). Decide it's a bit louder but not enough.

Stage 2: Think 'Feck this' and just get MPPSK

One thing; my 340i with MPPSK definitely has vapour coming out of both pipes at idle when in Comfort mode. Not sure once underway however.

[225]

Nice one. I may order this now and get rid of the gaffer tape version!

[Scaleybrat]

Anybody bought one of these online? Rybrook Warwick want £12.64 for p&p (presumably its coming from Germany) and was looking for another option. I know I could order from my local dealer but was hoping there was an ‘easier’ way of getting my hands on one.

[RustyBitz]

Originally Posted by Scaleybrat

Anybody bought one of these online? Rybrook Warwick want £12.64 for p&p (presumably its coming from Germany) and was looking for another option. I know I could order from my local dealer but was hoping there was an ‘easier’ way of getting my hands on one.

Same price as eBay. I might order one.

[Steve_M_Sport]

I've bought from rjberry his 340i exhaust backbox with black tips to fit to my 335D.

I know I need to remove the electric actuator from the exhaust & then open the flap and weld/glue it so the flap remains open - exactly how do I do this (or more likely the chap installing the new exhaust ?

I will contact Phil at Cotswold BMW tomorrow to buy the 340i rear diffuser so once this has been delivered it can be fitted - is this something the exhaust chap will replace or do I need to do it before I take the car - if so how do I remove/refit the diffuser ?

My insurers have confirmed as this does not affect the performance of the car my policy remains the same without any premium increase.

[225]

Originally Posted by Steve_M_Sport

I've bought from rjberry his 340i exhaust backbox with black tips to fit to my 335D.

I know I need to remove the electric actuator from the exhaust & then open the flap and weld/glue it so the flap remains open - exactly how do I do this (or more likely the chap installing the new exhaust ?

I will contact Phil at Cotswold BMW tomorrow to buy the 340i rear diffuser so once this has been delivered it can be fitted - is this something the exhaust chap will replace or do I need to do it before I take the car - if so how do I remove/refit the diffuser ?

My insurers have confirmed as this does not affect the performance of the car my policy remains the same without any premium increase.

Once it's open it stays open once unplugged

[Steve_M_Sport]

Originally Posted by 225

Once it's open it stays open once unplugged

I understood you had to actuate it first to open it , which I can’t do as I have a 335D ?

[225]

Originally Posted by RustyBitz

Same price as eBay. I might order one.

Where on eBay did you see this?

[Scaleybrat]

Originally Posted by 225

Where on eBay did you see this?

Good question - only one I can find on flea bay is north of £40 when you add the p&p.

[Rukka]

After seeing this thread resurrected, and that Photo Bucket had blocked all the links, I have now added the original pictures to the first post for those that like visuals

[AlwynMike]

Originally Posted by Rukka

After seeing this thread resurrected, and that Photo Bucket had blocked all the links, I have now added the original pictures to the first post for those that like visuals

Good man! Thanks you.

[dazwhite]

Originally Posted by Scaleybrat

Good question - only one I can find on flea bay is north of £40 when you add the p&p.

This is the only one i could find.

https://www.ebay.co.uk/itm/Original-...53.m1438.l2649

[paimon.soror]

The only poopy thing is people with F36's be careful. A lot of us have noticed that the F36 flapper doesn't exactly follow the same pattern as the other Fx's . I had to resort to using the steel wire mod since the F36 seems to only open when in motion above 3k rpm regardless of drive mode

[Abzynthe]

Originally Posted by paimon.soror

The only poopy thing is people with F36's be careful. A lot of us have noticed that the F36 flapper doesn't exactly follow the same pattern as the other Fx's . I had to resort to using the steel wire mod since the F36 seems to only open when in motion above 3k rpm regardless of drive mode

Thats interesting. I havent really been monitoring when mine opens, but I did a video the other day and the valve on mine opened up after a cold start, revving it a couple of times, then putting it in sport+ mode.

[225]

Originally Posted by dazwhite

This is the only one i could find.

https://www.ebay.co.uk/itm/Original-...53.m1438.l2649

That's the one I saw. 40 quid is a bit ott when gaffer tape is a quid.

[RustyBitz]

£45.48 for the part was just about to purchase until then. I will wait until I’m in Germany and get it delivered to the office.