Exhaust Burble problem

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Old Oct 11, 2022 | 06:10 PM
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Exhaust Burble problem

Greetings, I have recently bought a 2018 Amg Gtr.

I have a minor question but it is pretty strange which maybe could be a bigger underlying problem. The problem is that the car's exhaust burbling sound actually varies time to time. When I first got the car, it seems to burble a lot, now I feel like it's more softened. The car were all in working temperature and at same gear and rpms when comparing. The only difference is that I have installed the renntech valve control, and I don't believe that is the problem. Could what gas is used be a factor?

Thank you
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Old Oct 11, 2022 | 06:48 PM
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Old Oct 11, 2022 | 08:23 PM
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Originally Posted by Hhccc1
Greetings, I have recently bought a 2018 Amg Gtr.

I have a minor question but it is pretty strange which maybe could be a bigger underlying problem. The problem is that the car's exhaust burbling sound actually varies time to time. When I first got the car, it seems to burble a lot, now I feel like it's more softened. The car were all in working temperature and at same gear and rpms when comparing. The only difference is that I have installed the renntech valve control, and I don't believe that is the problem. Could what gas is used be a factor?

Thank you
I would say scan for codes if there might be stored soft codes but you did say there are burbles just reduced instead of completely no burbles. Although you mentioned the rennetch valve control not having to do with it, did you try unplugging it and restoring to stock at least for a couple of drives?
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Old Oct 11, 2022 | 10:10 PM
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Originally Posted by Hhccc1
Greetings, I have recently bought a 2018 Amg Gtr.

I have a minor question but it is pretty strange which maybe could be a bigger underlying problem. The problem is that the car's exhaust burbling sound actually varies time to time. When I first got the car, it seems to burble a lot, now I feel like it's more softened. The car were all in working temperature and at same gear and rpms when comparing. The only difference is that I have installed the renntech valve control, and I don't believe that is the problem. Could what gas is used be a factor?

Thank you
Fuel would play a part in that. Also, make sure you are in the right mode - it will only "burble" in Sport+ and Race. The sound is exhaust gas igniting post compression in the exhaust...
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Old Oct 12, 2022 | 02:17 AM
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Make sure the valve control is functional and valves are actually open
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Old Oct 12, 2022 | 03:13 AM
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Originally Posted by Hhccc1
Greetings, I have recently bought a 2018 Amg Gtr.

I have a minor question but it is pretty strange which maybe could be a bigger underlying problem. The problem is that the car's exhaust burbling sound actually varies time to time. When I first got the car, it seems to burble a lot, now I feel like it's more softened. The car were all in working temperature and at same gear and rpms when comparing. The only difference is that I have installed the renntech valve control, and I don't believe that is the problem. Could what gas is used be a factor?

Thank you
Everyone is being polite. It's likely the valve control - unless you don't understand the driving modes. Drive it in Race mode with manual shifting and allow compression braking at higher RPMs. There must be pops as the post ignition is guaranteed. If the valves are closed erroneously, there would still be pops but just quieter.
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Old Oct 13, 2022 | 02:05 AM
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Originally Posted by Hhccc1
Greetings, I have recently bought a 2018 Amg Gtr.

I have a minor question but it is pretty strange which maybe could be a bigger underlying problem. The problem is that the car's exhaust burbling sound actually varies time to time. When I first got the car, it seems to burble a lot, now I feel like it's more softened. The car were all in working temperature and at same gear and rpms when comparing. The only difference is that I have installed the renntech valve control, and I don't believe that is the problem. Could what gas is used be a factor?

Thank you
Is it possible the previous owner drove it like he stole it and you don't....and the ECU has relearned your driving (which may be less aggressive and therefore less pops/burbles)? Maybe reset the ECU?
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Old Oct 14, 2022 | 09:04 AM
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Stuck flap.
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Old Oct 15, 2022 | 01:00 PM
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The flap opening logic is not simple and not just open or closed. See the thread I started about this recently.
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Old Oct 24, 2022 | 02:58 PM
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Originally Posted by Skilly
Fuel would play a part in that. Also, make sure you are in the right mode - it will only "burble" in Sport+ and Race. The sound is exhaust gas igniting post compression in the exhaust...
mine does burble in Sport as well as in other modes. fl gtr
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Old Oct 24, 2022 | 03:24 PM
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Originally Posted by dav461
mine does burble in Sport as well as in other modes. fl gtr
Not if its a stock it doesn't.
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Old Oct 24, 2022 | 06:03 PM
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My GTR flaps open on sport+ and race mode only
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Old Oct 24, 2022 | 07:33 PM
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Originally Posted by Y.Haider
My GTR flaps open on sport+ and race mode only
Correct in terms of an auto setting but with your exhaust button you can open them in C or S too. It still wont creating that popping effect. though.

The "Burbles" are timing adjustments (retardation) where a small amount of unused fuel escapes to the exhaust chamber and ignites. That sound/happening is reserved for S+ and R settings only.
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