Exhaust Valve Question

[badwolfe]

Had my car (2021 A91) for a couple months now. Stock exhaust - Active Autowerks Catted DP. Car sounds phenomenal on start up but after a short while (30-45 seconds) but then quietens considerably. I know there are exhaust valves. Is there one in each exhaust outlet? If these remain open all the time will it keep that exhaust note like it has on start up? I've seen a thread where some have started car and then pulled a specific fuse and at least one vendor has a plug in device that allows you to control the opening and closing of the valve but it looks like it is for one side only (hence my question about is there one exhaust valve or two??) Newbie question for sure but TIA....

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[freeform911]

Stock exhaust is valved only on 1 side (passenger side)

Steve

 

[Crypto79]

The car comes with a button that controls the valve, it is the sport button. It’s alway tied to being active / comfort

 

[badwolfe]

The car comes with a button that controls the valve, it is the sport button. It’s alway tied to being active / comfort

Thanks but I've been reading that even in sport (which I have mine set to start up in sport mode) - it does not always stay open - but I could be wrong. As soon as I get a chance I'm going to go out and start the car and verify that valve is open and then wait for the car to quite down and see if it is still open. Car just sounds sooo different once it settles down after you first start it and it's just idling versus the initial start up.

 

[Evolution]

Thanks but I've been reading that even in sport (which I have mine set to start up in sport mode) - it does not always stay open - but I could be wrong. As soon as I get a chance I'm going to go out and start the car and verify that valve is open and then wait for the car to quite down and see if it is still open. Car just sounds sooo different once it settles down after you first start it and it's just idling versus the initial start up.

Funny thing is that the valve is closed during cold startup yet is louder than once warm and the valve is open. On cold start, the valve is closed until the car hits normal idle, then it opens (sport mode). After the car is warm, in sport mode, the valve is always open.

 

[ope_sry]

it sounds like you are just explaining the basic cold start cycle. Exhaust valve in sport is always open. You can pull the fuse taking power away from the exhaust valve completely if you want to confirm….but it should behave the same. Fuse is in the trunk, F203 7.5 amp.

 

[D3ad_Hand]

I could be wrong, but if you mean the car simmering down after you start it up, then that's the car just idling at a lower rpm. When you start it up it stays at a higher rpm for a few seconds then it jumps to a lower rpm. As for the exhaust valve, I always drive my car in sport so before I start it up, and when I shut off the car. The valve always stays open, if I'm not wrong if you shutoff your car in sport mode the valve stays open.

 

[badwolfe]

it sounds like you are just explaining the basic cold start cycle. Exhaust valve in sport is always open. You can pull the fuse taking power away from the exhaust valve completely if you want to confirm….but it should behave the same. Fuse is in the trunk, F203 7.5 amp.

Thanks for the reply - and yes - basically that's what I am doing (describing the start cycle) - I just am having a hard time wrapping my head around the - what is to my ears - such a difference in the tone of the exhaust between startup and a few seconds afterwards. I want the exhaust to always sound like it does at startup LOL.... Thanks again !

 

[badwolfe]

I could be wrong, but if you mean the car simmering down after you start it up, then that's the car just idling at a lower rpm. When you start it up it stays at a higher rpm for a few seconds then it jumps to a lower rpm. As for the exhaust valve, I always drive my car in sport so before I start it up, and when I shut off the car. The valve always stays open, if I'm not wrong if you shutoff your car in sport mode the valve stays open.

Thanks - going to verify the valve position when I start the car but I understand what you and Jesse are saying - it's just that first few seconds after startup are glorious!

 

[ope_sry]

I’m not entirely sure on the mechanics of what these cars do during the cold start cycle, but I imagine the wastegate is in a different position in addition to higher idle until it kicks over. With wide open exhaust I actually can’t wait for it to hit that quieter tone, it sounds like a D9 Caterpillar on cold start, offending everybody within a 100 yard radius ?

 

[badwolfe]

I’m not entirely sure on the mechanics of what these cars do during the cold start cycle, but I imagine the wastegate is in a different position in addition to higher idle until it kicks over. With wide open exhaust I actually can’t wait for it to hit that quieter tone, it sounds like a D9 Caterpillar on cold start, offending everybody within a 100 yard radius ?

LOL - it is a "bit loud" for sure! My previous "pleasure car" was a '17 GT350 with a Borla catback that was a "bit loud" as well. Kinda miss that sound but not sure I want to put on a new exhaust on - yet

 

[D3ad_Hand]

Could you possibly upload a clip of what u mean? We could better understand it that way

 

[GoldenEye]

Even in sport mode the valve is not open all the time. Put it in sport mode and do a cold start go back and look at the right side exhaust. You’ll see that the valve is closed. It will open in about a minute or so, as soon as it opens, pull the fuse and it’ll never close again. Problem solved…

 

[badwolfe]

Could you possibly upload a clip of what u mean? We could better understand it that way

I can do that - perhaps next week (I'm coming off surgery last week and can't really get out and do anything for like two weeks) but I'll post something up as soon as I can get outside.... Thx!

 

[badwolfe]

Even in sport mode the valve is not open all the time. Put it in sport mode and do a cold start go back and look at the right side exhaust. You’ll see that the valve is closed. It will open in about a minute or so, as soon as it opens, pull the fuse and it’ll never close again. Problem solved…

Thx - That's on my list of things to try as soon as I can get outside... Thx!

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