[kamek]

I asked this in the other thread but I wanted to get the question in here as well: My big question is does this have any negative effects on the car or how it warms up? BMW engineered the exhaust to have only one flap open for a reason, but that reason to me is unknown.

[KAP8]

Originally Posted by Kief

Despite him referencing his X4 M40i, I'm thinking DBU is correct about this:

OK. I unplugged mine on my former 2009 335i and found the drone annoying, so I soon plugged it back in. I haven't tried on my 435i with M performance exhaust or the new M40i.

[BobsM3Coupe]

Originally Posted by kamek

I asked this in the other thread but I wanted to get the question in here as well: My big question is does this have any negative effects on the car or how it warms up? BMW engineered the exhaust to have only one flap open for a reason, but that reason to me is unknown.

Usually, one flap open on a cold start is to warm up the catalyst converter as quick as possible for lower emissions. Some other manufacturers do the same thing.

[j1980mac]

I know this sounds contrary to having an M40i, but is there anyway to code the exhaust to keep the flaps closed on startup?

For example, on startup:

If in Sport, Sport +, etc, keep open.
If in Comfort or Eco mode when started, close exhaust flaps.

Any thoughts?

[kamek]

Originally Posted by j1980mac

I know this sounds contrary to having an M40i, but is there anyway to code the exhaust to keep the flaps closed on startup?

For example, on startup:

If in Sport, Sport +, etc, keep open.
If in Comfort or Eco mode when started, close exhaust flaps.

Any thoughts?

Only one exhaust is open during normal startup.

[sinbad4]

Originally Posted by j1980mac

I know this sounds contrary to having an M40i, but is there anyway to code the exhaust to keep the flaps closed on startup?

For example, on startup:

If in Sport, Sport +, etc, keep open.
If in Comfort or Eco mode when started, close exhaust flaps.

Any thoughts?

I haven't seen anything about this.. being able to code to various mapping.

I believe the JB4 module, however, lets you turn on and off with your blinker or some such trickery.

[lililii]

Hey DBU

I just did this on my 2018 x4 m40i. I think the flap is now permanently closed. I took it out drove it for a while and when I got back the left side exhaust is cold still, the right exhaust is really hot. I was able to reach down and press on the valve to manually open it. It was cold too...

Yours is working just fine? The flap will open right when you start the engine? There wasn't any vacuum from either hose when i start the car.. bypassing the solenoid is supposed to have the vacuum on the valve all the time and thus the flap would be always open, right?.. cant figure out whats going on, supposed to be a very easy mod

Originally Posted by DBU

I am not familiar with the G03 (X3 M40i), but I can tell you how it works on the F26 (X4 M40i). Keep in mind we have different motors (B58 vs N55), but I wouldn't be surprised if BMW left this unchanged on the G03.

To check this, take a look at under the car, behind the driver's side rear wheel. You will see the exhaust pipe has a valve that close and open the exhaust flap. You should be able to press firmly on the lever and by doing so open the valve. It is spring loaded and takes a firm press to move.

If you want it to stay open (for better sound), go to the trunk of the car. On the driver's side, you probably have a hard cover that is easily removed to gain access to some electrical modules (radio?)

Now look towards the very rear of the car and you should see a small solenoid attached to the chassis with a rubber mount. It will have two vacuum lines and an electrical connection. To leave the exhaust flap open whenever the motor is running, disconnecty both vacuum hoses from the solonoid and connect the two hoses with a male/male vacuum connector, bypassing the solonoid altogether. I found that a common garden sprinkler connector also works.

Whenever the motor starts, vacuum is sent straight to the valve and it will open - and stay open.

On the X4, engaging sport modes does not automatically open the valve. It seems the valve opens when the solonoid receives a signal from the computer at some point when the motor is asked to produce max, or near max, power.

[DBU]

Originally Posted by lililii

Hey DBU

I just did this on my 2018 x4 m40i. I think the flap is now permanently closed. I took it out drove it for a while and when I got back the left side exhaust is cold still, the right exhaust is really hot. I was able to reach down and press on the valve to manually open it. It was cold too...

Yours is working just fine? The flap will open right when you start the engine? There wasn't any vacuum from either hose when i start the car.. bypassing the solenoid is supposed to have the vacuum on the valve all the time and thus the flap would be always open, right?.. cant figure out whats going on, supposed to be a very easy mod

I wish I could help you here. I have had periods where the flap would stay open all the time, even with the motor off. At other times the vacuum appeared to not be strong enough to open the flap at startup. It would then take just a light(er) pressure on the lever to open it (motor running). Currently, my flap close after car has been stopped for 20+ minutes, but it opens at each start. There is a very distinct sucking sound when the flap opens and of course the exhaust tone/volume changes dramatically. I have had the male/male connection on and off a number of times (another long story) and I suspect that connection isn't always as air tight as it should be. I dunno.

If you disconnect the vacuum tubes, start the car and neither tube is sucking air, well, that would point to a failed vacuum system OR there is something else at work here that we don't (yet) understand. I have always assumed that vacuum was supplied whenever the motor was running, but it is conceivable that the BMW engineers have concocted a combination of vacuum AND electrical signal. Wouldn't be the first time BMW has over engineered something simple...


PS: My wife claims she sometimes can hear a hissing sound in the car. My old ears don't hear it, but I have heard it close to the exhaust flap (when it wasn't working). Wife confirmed the sound to be "very similar..." Go figure..

[TxHornX3M40iGuy]

This is not helpful to those looking for more sound in comfort or eco mode...but for startup noise, I discovered that if I just sit in the car, hit sport, then start it up, it is definitely louder. You guys are way above my head on this solenoid and vacuum talk. I have no clue. I have recently noticed though, that when switching from comfort to sport in some instances the exhaust valve does not adjust (meaning I cannot make it pop and burble like I normally can by speeding up in first, then backing off etc. May have to get the dealer to check that too.

[ParadigmDawg]

Originally Posted by TxHornX3M40iGuy

This is not helpful to those looking for more sound in comfort or eco mode...but for startup noise, I discovered that if I just sit in the car, hit sport, then start it up, it is definitely louder. You guys are way above my head on this solenoid and vacuum talk. I have no clue. I have recently noticed though, that when switching from comfort to sport in some instances the exhaust valve does not adjust (meaning I cannot make it pop and burble like I normally can by speeding up in first, then backing off etc. May have to get the dealer to check that too.

Seems really gas and temperature dependant to me. I know when I have a good mixture of race gas and it is a tad cooler in the mornings, I make all kinds of noise coming out of the garage and down the street.

When it is warmed up, it makes all kinds of noise going down any road.

Oh wait....you haven't boosted your's yet so your's is just being silly. Give that thing a little boost and see what you have been missing....

Seriously though, mine sounds like cannons going off when I am in Map 5 and on 96+ octane. It's close to the sound of my AMG which is a 605 hp V8.

[TxHornX3M40iGuy]

Originally Posted by ParadigmDawg

Seems really gas and temperature dependant to me. I know when I have a good mixture of race gas and it is a tad cooler in the mornings, I make all kinds of noise coming out of the garage and down the street.

When it is warmed up, it makes all kinds of noise going down any road.

Oh wait....you haven't boosted your's yet so your's is just being silly. Give that thing a little boost and see what you have been missing....

Seriously though, mine sounds like cannons going off when I am in Map 5 and on 96+ octane. It's close to the sound of my AMG which is a 605 hp V8.

Can't wait. Almost went JB4, decided to hold off to see what Dinan offers and hoping they will have a full upgrade at some point, not just a stage 1. But I've been following you guys and the numbers...you guys are running legit low 12 second quarters and 4.1 or so 0-60? I'd love to hit flat 4 seconds on 0-60 or even 3.9 to match the M3.

[TxHornX3M40iGuy]

Originally Posted by ParadigmDawg

Seems really gas and temperature dependant to me. I know when I have a good mixture of race gas and it is a tad cooler in the mornings, I make all kinds of noise coming out of the garage and down the street.

When it is warmed up, it makes all kinds of noise going down any road.

Oh wait....you haven't boosted your's yet so your's is just being silly. Give that thing a little boost and see what you have been missing....

Seriously though, mine sounds like cannons going off when I am in Map 5 and on 96+ octane. It's close to the sound of my AMG which is a 605 hp V8.

And I think you should throw up a video with sound so we can hear yours.

[iManu]

Originally Posted by TxHornX3M40iGuy

Can't wait. Almost went JB4, decided to hold off to see what Dinan offers and hoping they will have a full upgrade at some point, not just a stage 1. But I've been following you guys and the numbers...you guys are running legit low 12 second quarters and 4.1 or so 0-60? I'd love to hit flat 4 seconds on 0-60 or even 3.9 to match the M3.

Originally Posted by TxHornX3M40iGuy

Can't wait. Almost went JB4, decided to hold off to see what Dinan offers and hoping they will have a full upgrade at some point, not just a stage 1. But I've been following you guys and the numbers...you guys are running legit low 12 second quarters and 4.1 or so 0-60? I'd love to hit flat 4 seconds on 0-60 or even 3.9 to match the M3.

Hey for the 0-60, I already hit 3.9-4.1! Here are the draggy results.

[Jayf30]

Originally Posted by emmanuel.yoo

Hey for the 0-60, I already hit 3.9-4.1! Here are the draggy results.

[ParadigmDawg]

Originally Posted by TxHornX3M40iGuy

And I think you should throw up a video with sound so we can hear yours.

Just come over

[ParadigmDawg]

Originally Posted by emmanuel.yoo

Hey for the 0-60, I already hit 3.9-4.1! Here are the draggy results.

I have to find a flatter road.....

What map and octane?

What was the DA?

Are you running the IAT Spoof?

[TxHornX3M40iGuy]

Originally Posted by ParadigmDawg

Just come over

Are you in Austin or Dallas???

[TxHornX3M40iGuy]

Originally Posted by emmanuel.yoo

Hey for the 0-60, I already hit 3.9-4.1! Here are the draggy results.

WHOA!!!! Juicy! So the key is a flat or slight downslope.
Seriously though...I'd love to know what your setup is...intake, tune, octane, etc. That's pretty solid.

[ParadigmDawg]

Originally Posted by TxHornX3M40iGuy

Are you in Austin or Dallas???

Bite your tongue Son, I am in Fort Worth.

[ParadigmDawg]

Originally Posted by TxHornX3M40iGuy

WHOA!!!! Juicy! So the key is a flat or slight downslope.
Seriously though...I'd love to know what your setup is...intake, tune, octane, etc. That's pretty solid.

A 1% slope is NHRA standard.

One thing I am uncertain about is the 1ft rollout on a Dragy. Is it calculated in there or not? If not, we are probably 0.2-0.3 seconds quicker than what is showing.

[TxHornX3M40iGuy]

Originally Posted by ParadigmDawg

Bite your tongue Son, I am in Fort Worth.

HAHAHA. Well at least it's not Arlington or Bedford?

I make it up to the DFW area every few months to see family. I will have to set that up.

[ParadigmDawg]

Originally Posted by TxHornX3M40iGuy

HAHAHA. Well at least it's not Arlington or Bedford?

I make it up to the DFW area every few months to see family. I will have to set that up.

Today is the first day I have seen another M40 around town and it was in my neighbors driveway. He is a diehard Benz guy so I think it was a visitor. You won't believe this but it had a UT sticker on it. Did you come over after all?