[eamon]

Ah I did the trunk cable diconnector thing, but I've read a lot of posts about problems down the road so now I've turned to this.
The problem is I cant get the tube off... And am I supposed to put the BB in the tube or in the metal rod thing that the tube is covering?

Is it hard to slide the tube back on?

[N54bimmer]

I justdid the golf tee mod this morning, it so easy!
Look at your left tail pipe, youll see a arm on top of it, connected to that is a circular thing with a black rubber hose connected to it. The rubber hose is the vaccum, what you want to do is this:
1) spray wd40 around the hose because its usualy stuck into the metal "nipple"
2) with a paper towel twist and pull the hose off of the nipple
3) either use a golf tee to block off the hose from sucking in air, or use duct tape and seal it good.
4) use a zip tie or duct tape to tie to hose onto that metal nipple to avoid having it hang down. When i say tie it I dont mean putting to nipple into the rubber tube lol I mean tie it to it!

[secretsquirrel]

Originally Posted by eamon

Ah I did the trunk cable diconnector thing, but I've read a lot of posts about problems down the road so now I've turned to this.
The problem is I cant get the tube off... And am I supposed to put the BB in the tube or in the metal rod thing that the tube is covering?

Is it hard to slide the tube back on?

There's not troubles with unplugging the trunk cable. LOL.

[racerbruce]

Greetings from Seattle -
I've had my 2013 335is E93 hardtop/convertible for a few weeks; yesterday I ID'd the driver side muffler diverter assembly under the LR corner of the car; I pushed on the valve linkage and could manually actuate the valve; then I removed the vacuum tube easily with pliers and reinstalled the vacuum tube; using a flashlight I looked into the driver side exhaust pipe tip at the rear of the car; I could see the diverter valve "flapper" or "butterfly" and it was in the open or not-closed position with the engine off; I started the engine and immediately looked again and the flapper or butterfly had closed off, preventing any exhaust from existing the driver side exhaust pipe at the rear of the car; appx 30 seconds later I heard and felt exhaust flow and checked with the flashlight and the flapper or butterfly had opened and was allowing exhaust to flow out of the driver side exhaust pipe; I allowed the engine to run appx 15 min at idle and then turned off the engine; I checked again and the flapper or butterfly remained in the open position; my hypothesis is the flapper or butterfly only closes on startup for appx 30 seconds and then opens to allow exhaust to flow from both the driver side and passenger side exhaust tips at the rear of the car; I presume the signal comes from the electronic control unit (ECU) to open the flapper or butterfly occurs appx 30 seconds after startup; other posters say this valve while closed warms the catalytic converter quicker to enhance pollution control of the exhaust gases quicker; if all of this is true, then there is no need to bypass this valve as it remains open all the time except upon startup; I am unsure if the valve actuates and closes upon a warmed up stop/start of the engine; I will continue to monitor and provide additional info to this thread.

[Bimmer_Bro]

Originally Posted by racerbruce

Greetings from Seattle -
I've had my 2013 335is E93 hardtop/convertible for a few weeks; yesterday I ID'd the driver side muffler diverter assembly under the LR corner of the car; I pushed on the valve linkage and could manually actuate the valve; then I removed the vacuum tube easily with pliers and reinstalled the vacuum tube; using a flashlight I looked into the driver side exhaust pipe tip at the rear of the car; I could see the diverter valve "flapper" or "butterfly" and it was in the open or not-closed position with the engine off; I started the engine and immediately looked again and the flapper or butterfly had closed off, preventing any exhaust from existing the driver side exhaust pipe at the rear of the car; appx 30 seconds later I heard and felt exhaust flow and checked with the flashlight and the flapper or butterfly had opened and was allowing exhaust to flow out of the driver side exhaust pipe; I allowed the engine to run appx 15 min at idle and then turned off the engine; I checked again and the flapper or butterfly remained in the open position; my hypothesis is the flapper or butterfly only closes on startup for appx 30 seconds and then opens to allow exhaust to flow from both the driver side and passenger side exhaust tips at the rear of the car; I presume the signal comes from the electronic control unit (ECU) to open the flapper or butterfly occurs appx 30 seconds after startup; other posters say this valve while closed warms the catalytic converter quicker to enhance pollution control of the exhaust gases quicker; if all of this is true, then [...]

This thread is 12 years old...

The flap is closed on start up to warm the cats yes and noise reduction. However no it is not open all the time.... not at all. It opens and closes during driving. When cruising it will always be closed to reduce drone. It most likely opens with higher rpm/ throttle. I can't remember if it behaves differently in sport mode.

[racerbruce]

Originally Posted by Bimmer_Bro

This thread is 12 years old...

The flap is closed on start up to warm the cats yes and noise reduction. However no it is not open all the time.... not at all. It opens and closes during driving. When cruising it will always be closed to reduce drone. It most likely opens with higher rpm/ throttle. I can't remember if it behaves differently in sport mode.

How have you determined it opens and closes during driving.

[Saif2018]

Originally Posted by Bimmer_Bro

This thread is 12 years old...

The flap is closed on start up to warm the cats yes and noise reduction. However no it is not open all the time.... not at all. It opens and closes during driving. When cruising it will always be closed to reduce drone. It most likely opens with higher rpm/ throttle. I can't remember if it behaves differently in sport mode.

Correct, it opens based on how much throttle/rpm, it's never open all time time in stock configuration, even in sports mode.

[Saif2018]

Originally Posted by racerbruce

How have you determined it opens and closes during driving.

Just so your aware the Golf T mod enhances the exhaust note a little but it doesn’t cause drone.

Muffler delete causes drone but you can reduce it to an extent using resonators like Vibrant.

[GnomeChild]

Does anyone know how I can diagnose the cause of an exhaust flap that is constantly open? Lol

Funny how this thread is about achieving that very function but I am looking to reverse it and regain this feature

I bought the car secondhand about 5 years ago and it seems like when I looked back in the trunk, my actuator was unplugged. I plugged it back in maybe 2 years ago thinking I "fixed" something (HOORAY!) but I just checked about 30 minutes ago and my flap is still open, even with the car off, just barely started, warmed up at idle; etc. I have verified I have all the vacuum lines plugged in except for the main line that goes to the engine bay (I wouldn't even know where that one even goes).

Could the previous owner have disabled it through coding? Could my electronic actuator be bad? Is there a specific fuse maybe he unplugged? I hooked up Carly really quick to the car (because it was the most convenient) and the option to code in or out the "Exhaust Flap" feature was grey out and it stated that it was not an option available on my car. I couldn't find it either when looking through the actual coding modules

I tried checking to see if my flap was tampered with like welded open or something by closing the valve manually using the actuator arm with the car off but it does move, just springs back open automatically. Can anyone confirm that the flap is open when the car is off and only closes at start?

Is there any way the mod is performed that doesn't include the usual methods yet still results with a stuck-open flap? How is this mod performed if all the vacuum lines are still plugged in? Should I pull the line and check to see if there is a BB in there? Should I check all the lines to see if there are any zipties?


EDIT
Reason for doing so is that I plan to eventually do M-module retrofit with the cluster, button, and misc mechanical mods that are effected by M-Drive + an M-Performance exhaust. The e90 specific PE still has the exhaust flap present. With M-Modules, I believe there is a function that opens the valve and keeps it open if the M-button is pressed/M-Drive mode is active, even though M cars never came with an exhaust flap on their factory exhausts. It would be nice (and subsequently pretty baller) if I could regain function of the flap just in case my planned exhaust mods are too loud/droney during lower RPMs or daily driving; the flap could cut down on some of that yet still rip at high RPMs or whenever I decide I want a louder exhaust and activate M-Drive mode. Basically I can have this "mod" active or inactive in seconds at the simple push of a single button


EDIT 2
So I was doing a little digging and found out that a permanently open flap may be a function of my JB4 (Menu 4, Option 5). I've toggled that option multiple times and can confirm that once it is toggled off, I can hear the metal flap rattle in the back, my exhaust get quieter, no visible exhaust seen or felt when standing at the rear of the car, and the flap is fully closed. I've basically confirmed my flap works correctly so seems like there is nothing to "unmod". Flap even seems to be functioning normally as after about 15-20 seconds, it opens back up and I can see/hear/smell/feel exhaust and visibly see the flap open. However, if I turn the car off and let it sit for a few minutes and start it back up again, my flap never closes and is stuck open again. Car has both JB4 with MHD BEF so I'm wondering if there is a toggle on the MHD side and I've completely forgotten the parameters of the tune I flashed...

Honestly considering reverting back to stock DME completely and throwing the JB4 up on the classifieds... I don't even use it since I haven't done any supporting mods yet, don't want to exacerbate my wastegate rattle, and I'm always in Map 0/Map 4. Maybe this is the final push I need to just got full MHD flash instead of the combo...


EDIT 3
What a journey this is turning out to be lol
Just got back in from flashing the car back to stock DME through MHD and activating JB4 Map 0. The car is effectively stock in all its wastegate rattling glory. However, I can now confirm that the flap operates correctly with every start up and my loud cold starts are BACK baby
That essentially leaves the culprit to be the MHD BEF which could mean all MHD OTC flashes include the flap disable as part of the flash... I wonder how the guys flashing 1M tunes to the DME to enable M-Drive functions are leaving the flap function untouched. Seems like a custom flash may be needed. Maybe it is simply part of the "decreased noise on cold start" option on the MHD flash page but if that's the case wouldn't keeping the flap closed on cold starts help more with loud exhaust notes? Maybe it is assumed that everyone modding and flashing their cars are going to go aftermarket exhaust anyway so MHD is programmed to code out the flap. If so though wouldn't people replacing their stock exhaust for aftermarket ones without the flap be throwing the "flap code" when scanned through INPA/Dealer computers? Unless of course they are just doing the manual Golf-Tee mod instead of just leaving the electronic vacuum actuator unplugged. More exhaustive (no pun intended lol) testing may be required.........



TL;DR
I care a lot about my little flap that could, can you tell?

[C4maro]

The golf tee mod fixed my limp mode

I'd get limp mode at 40% throttle - knock sensor low input - but if I drove it for 20 minutes and shut it on and off then it wouldn't go into limp. So I've just been living with it for a while. Did the golf tee mod to see if it would quiet the rattle i have on startups(it didnt fix that). I've been driving my car stock everyday for years now and the car feels more alive at low rpm, it feels like it had a clogged air filter and now its breathing again.. maybe my mufflers clogged. The limp mode was a consistent reoccurring thing and the moment I did this it doesnt go into limp.

[lowrydr310]

Originally Posted by racerbruce

I presume the signal comes from the electronic control unit (ECU) to open the flapper or butterfly occurs appx 30 seconds after startup; other posters say this valve while closed warms the catalytic converter quicker to enhance pollution control of the exhaust gases quicker; if all of this is true, then there is no need to bypass this valve as it remains open all the time except upon startup; I am unsure if the valve actuates and closes upon a warmed up stop/start of the engine; I will continue to monitor and provide additional info to this thread.

If your valve is rattling (like mine was) then that is the reason do this modification. Also if your valve is rattling, you will definitely hear that it opens and closes during normal operation and not just at startup.

I have no issue with normal functioning of the valve. I looked into the $100 repair kit to silence a rattling valve but figured I'd try this first and it worked fine. Exhaust note is slightly louder when cruising but not terrible.

[E93Seattle (Racerbruce)]

Originally Posted by lowrydr310

If your valve is rattling (like mine was) then that is the reason do this modification. Also if your valve is rattling, you will definitely hear that it opens and closes during normal operation and not just at startup.

I have no issue with normal functioning of the valve. I looked into the $100 repair kit to silence a rattling valve but figured I'd try this first and it worked fine. Exhaust note is slightly louder when cruising but not terrible.

thank you lowry,
some months ago i purchased a steel ball from ace hardware that has an OD just slightly larger than the ID of the vacuum hose that connects to the exhaust flap.

i disconnected the vacuum hose from the exhaust flap and inserted the steel ball in the vacuum hose (interference fit) and then reconnected the vacuum hose on the diaphram's nipple connection.

this keeps the exhaust flap open 24/7 and is visibly undetectable vs a golf tee hanging out of the vacuum hose.

the already agressive and wonderful sound of the 335is oem performance exhaust mufflers is clearly louder upon startup during the first minute or so of dme designed rpm increase.

[C4maro]

Is the flap controlled by engine vacuum or a little vacuum pump that’s powered electrically?

[lowrydr310]

Originally Posted by C4maro

Is the flap controlled by engine vacuum or a little vacuum pump that’s powered electrically?

Neither. Theres a mechanical vacuum pump driven by the timing chain which provides consistent vacuum to the brake booster, wastegate actuation system, and the exhaust flapper. In the case of the wastegate actuation and exhaust flapper, electrically operated solenoids open to apply vacuum to either the wastegate actuators on the turbos or to the exhaust flap actuator.

[C4maro]

Originally Posted by lowrydr310

Neither. Theres a mechanical vacuum pump driven by the timing chain which provides consistent vacuum to the brake booster, wastegate actuation system, and the exhaust flapper. In the case of the wastegate actuation and exhaust flapper, electrically operated solenoids open to apply vacuum to either the wastegate actuators on the turbos or to the exhaust flap actuator.

So maybe that is why my car feels more alive, maybe the flapper was leaking vacuum causing the waste gates to not get correct vacuum?

[lowrydr310]

Originally Posted by C4maro

So maybe that is why my car feels more alive, maybe the flapper was leaking vacuum causing the waste gates to not get correct vacuum?

Hard to say. I accidentally forgot to reconnect my flapper vacuum line at the T fitting after installing a new charge pipe and I didn't notice any difference. Car ran and boosted just fine. Those big boost canisters work pretty well. I've disconnected the lines to them an hour after I turned my car off and there was still a lot of vacuum stored.

[AWD Addict]

Originally Posted by Bimmer_Bro

This thread is 12 years old...

The flap is closed on start up to warm the cats yes and noise reduction. However no it is not open all the time.... not at all. It opens and closes during driving. When cruising it will always be closed to reduce drone. It most likely opens with higher rpm/ throttle. I can't remember if it behaves differently in sport mode.

The drone was unbearable for me. I plugged it back in.

It was nice to not hear it rattle at startup, and it sounded a bit throatier, but there's no performance increase.