[BMW FOREVER]

I was at the local BMW showroom today when I noticed something different about the 528i on display..it had the exhaust valve just like the 550i! Wonder what changes it would make to the car..

[Boss330]

The F11 523i, 528i and 530i have allways had the valved exhaust. The F10 versions of the 523i, 528 and 530i didn't though.

[Grover432]

What does it do?

[HDEddie1]

It'll make the car quiet, FOR SURE, on start up and part throttle. The flap will open after about 3K. Its vacuum operated and controlled by engine's ECU. I really think BMW is trying to mask some of the "4 cylinder sound" that is so prevalent at lower RPMs with all 4 cylinders. Grin and bear it.

[dangom808]

My 2011 528 w N52 engine has this as well

[Sunny 528i]

my 2012 528i with N20 also has the valve, not anymore due to the custom exhaust upgrade

[lsturbointeg]

So what's already quiet making it even more quiet Lol!

[493263]

Originally Posted by lsturbointeg

So what's already quiet making it even more quiet Lol!

It's a 5 series. It's meant to be quiet. Most of us on this board probably want more sound. But the vast majority of 5 series buyers prefer a relatively quiet engine. The average buyer is about 55 years old and doesn't care about engine sounds.

[gatorfast]

Just looked and mine has the valve too. Prob would have never noticed it without this thread. Ive only had the car a week or so but havent noticed any change in volume when I step on so I guess the valve probably doesnt do much.

[SonicEndeavor]

Originally Posted by gatorfast

Just looked and mine has the valve too. Prob would have never noticed it without this thread. Ive only had the car a week or so but havent noticed any change in volume when I step on so I guess the valve probably doesnt do much.

The 528i has an artificial engine sound pumped into the cabin so you probably won't hear minor changes in the exhaust note from inside the car.

[dangom808]

Originally Posted by SonicEndeavor

The 528i has an artificial engine sound pumped into the cabin so you probably won't hear minor changes in the exhaust note from inside the car.

Please tell,me you're joking!

[SonicEndeavor]

Originally Posted by dangom808

Please tell,me you're joking!

No, it's not a joke. There's an engine noise synthesizer located just above the rear wheel well on the drivers side that feeds into the audio system to give the 4 cylinder a slightly better sound. I don't think your N52 has it, but the N20's do.

[dangom808]

Originally Posted by SonicEndeavor

No, it's not a joke. There's an engine noise synthesizer located just above the rear wheel well on the drivers side that feeds into the audio system to give the 4 cylinder a slightly better sound. I don't think your N52 has it, but the N20's do.

Thanks for that informative insight. Very interesting BMW would go through the trouble of synthesizing an engine sound. Learn something new every day right.

[493263]

Originally Posted by dangom808

Thanks for that informative insight. Very interesting BMW would go through the trouble of synthesizing an engine sound. Learn something new every day right.

They've been doing it for years. I think it started with the Z4

[Grover432]

The 535 has the same valve. I believe it is in the open position when the car is first started and then closes shortly thereafter. I'm wondering if it isn't emissions related on warm up and then opens under heavy throttle.

[geminiys]

The valve is to warm the engine faster, especially on a cold start and opens whenever RPM is above 2000. The valve is also related to emission control that if I am most mistaken was introduced with OBDII back in 1996.

[SonicEndeavor]

The valve is for noise control, not emissions or warm-up. They're putting the active exhaust valve on the 535's? My 2014 certainly doesn't have an active exhaust. Maybe this started with the 2015's?

[snj1013]

Originally Posted by dangom808

My 2011 528 w N52 engine has this as well

No it doesn't. What makes you think so?

[geminiys]

Originally Posted by SonicEndeavor

The valve is for noise control, not emissions or warm-up. They're putting the active exhaust valve on the 535's? My 2014 certainly doesn't have an active exhaust. Maybe this started with the 2015's?

You might be right but my 1997 328 with 6 cylinders has it too. The 4 cylinders in the past (older body styles) never had it as exhaust was only single pipe but 6, 8, and 12 were/are dual pipe exhaust and I believe starting from 1996 have valve in the second pipe. The F10 528 starting from 2012 are 4 cylinders but do have dual pipe exhaust but don't have the valve. For whatever reason BMW decided to put on 4 cylinder cars.

[SonicEndeavor]

Originally Posted by geminiys

You might be right but my 1997 328 with 6 cylinders has it too. The 4 cylinders in the past (older body styles) never had it as exhaust was only single pipe but 6, 8, and 12 were/are dual pipe exhaust and I believe starting from 1996 have valve in the second pipe. The F10 528 starting from 2012 are 4 cylinders but do have dual pipe exhaust but don't have the valve. For whatever reason BMW decided to put on 4 cylinder cars.

It depends on the exhaust design. The valve helps reduce drone in the lower RPM range like when your're cruising through town or on the freeway. Stomp on the gas and the valve opens to let the growl come out. Some exhaust designs have more drone than others, so that's why the active exhaust flapper is used on some models and not others.

[BMW FOREVER]

so wait..even the 2012 N20 528i gets the synthesized sound or is it only applicable to later model years?

[SonicEndeavor]

Originally Posted by BMW FOREVER

so wait..even the 2012 N20 528i gets the synthesized sound or is it only applicable to later model years?

Not sure, but if you pull the trunk liner away with one hand and snap a pic with your phone in other hand, you'll see a small silver box mounted on the back side of the drivers side rear wheel well if you have the synthesizer.