PorscheACC

Have you all noticed a deep exhaust sound at startup on Cayenne S 2019?

It goes away after a few seconds after the engine warms up.

Is there a way to modify something to leave the deep exhaust sound? Its a great deeper exhaust sound..

It seems like there are some exhaust valves that are open when you first start the engine, and then they close up. If there is a small mod that keeps those valves open, it may be nice to explore this option.

My vehicle didn't come with the PSE option, and it is $3000.00 to add it..

obbob

Cold starts idle higher which is why they are louder.

You would have to tune the car to idle higher.

PorscheACC

Nope.. It is not higher rpm idling, and definitely, you don't want to increase your base ram.

I can go 2500 or even 3000 rpm after warmup and the sound is way muffled compared to the cold start..

There is definitely some valve/flap opened during cold starts and closes after the engine warmup period.

obbob

If you are convinced that it is an exhaust valve, then get an aftermarket exhaust valve controller. It will override the OEM exhaust flap control. An even easier method is to get underneath the car and just disconnect the vacuum lines from the valves. This will leave the valves permanently opened but also disable the exhaust button functionality.

PorscheACC

Great points. I don't have PSE,

When you say "disable the exhaust button functionality", are you referring to the PSE Sports button that enables/disables the PSE deeper sound exhaust option?

Mr_Marty

Probably not the exhaust you're hearing. Probably the vapor canister. When you first start the car a valve opens that purges the vapor canister. Takes about 30 seconds to burn off the fuel that has accumulated. Then the valve closes.

SF_

For what it's worth, I got the exhaustmeister (remote exhaust valve controller) for my M5 with the stock exhaust. I could barely tell the difference when driving the car with the valves open vs. closed.

Galion

No valves, just richer air/fuel mixture
Get a cat bypass delete from Soul Performance.

solrac6262

I have PSE but the vacuum lines are not the way they used to be, like my 991 I was able to disconnect, on the cayenne the tech told me its electronic

PorscheACC

So maybe there are some electrical connectors instead..? 🙃

alpine-al

I agree that the louder start-up is not related to exhaust valves and that it caused by a short period of richer air/fuel mixture, which is done intentionally to warm up the catalytic converters faster and reduce emissions.

Mike Murphy

Wouldn’t it be leaner air/fuel that heats the cats? And don’t most cars pump air before or after the engine to increase oxygen to the exhaust that adds to the cat heat-up?

PorscheACC

That's true, now that I remember my old Mercedes SUVs issues.

The oxygen sensors have a heater filament, and the sensor needs to reach the proper temperature to work correctly.

The engine uses a default richer fuel mixture setting until the oxygen sensors are ready to monitor correctly the air/fuel mixture.

Though, I just found some information on Mercedes flap removal to make the exhaust sound louder.

The excerpt below sounds pretty much like Porsche PSE technology that opens the flaps electronically.

Maybe the Porsche exhaust flaps are opened until the oxygen sensors are warmed up, since the deeper exhaust sound does not happen after the vehicle is warmed up.

----‐‐-----------------

Mercedes Exhaust Flap TechnologyMercedes-Benz flap technology works in conjunction with DYNAMIC SELECT Driving Modes. When a mode is selected, the exhaust flaps, located inside the exhaust near the rear bumper, allow more or less air through the exhaust piping. By allowing more air through, the engine will sound more aggressive and can possibly add a little bit of power, sacrificing efficiency and noise reduction.

How Much Power Can it Add?

Actually, the exhaust flaps have more to do with sound than actual performance. If you are driving an AMG SL65, you might notice more of a power gain than if you are driving a CLA45, but in reality, it is only a few horsepower. That being said, the sound change is like magic and gives driving a really fun twist.

Flap Removal

Although we don’t recommend doing this, nor do we see the benefit, you will find countless articles online about drivers removing these flaps from their exhaust setups. The reason for this is to make sure the exhaust is wide open 24/7

Timmy222

I have made a little video so you can hear the wonderful startup rumble and the quieter idle that follows.

See .

dasams

On a cold startup, the air/fuel ratio is richer to maintain combustion. Reason is that some of the fuel may not have vaporized and won’t combust hence extra fuel is needed. We used to do this manually back in the day by using the choke. RPMs are up a bit so the engine won’t stall and extra air is added downstream to burn off the extra fuel. It’s this secondary burn that increases the sound of the exhaust. I think 🤔