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Exhaust Valve Controller: Great Bang for the Buck Upgrade
Hey Guys:
Long overdue update on our 25 G63–we installed an exhaust valve controller to get the most out of the stock exhaust system.
This is the rare upgrade that offers a proper value:spend ratio. More so if you can manage to get the ASR version—they supply the Renntech version and can be had at half the price.
Sound character remains unchanged; there is just more of it. Probably 25% more sound, grunt and rumble. Gone is the lame/lazy raspiness of the exhaust unless you are flat out and over 4k RPM.
If this cost $1500, you would be disappointed. Given the price of replacement exhaust systems ($9000 or thereabouts), this really is just right.
I need to, and will, make some videos. Switching between stock valve operation and wide open (which you still can’t achieve by pressing the button in the cabin, mind you) takes a single button press.
Expectation Management: You won’t be awe struck. You will notice the difference, however.
Sounds like a solid mod. Good tip on the ASR version being the same as Renntech for half the price. Keeping the stock character but with 25% more rumble is exactly what most people want from these trucks without going for a full, expensive system. Thanks for sharing the real-world feedback.
Long overdue update on our 25 G63–we installed an exhaust valve controller to get the most out of the stock exhaust system.
This is the rare upgrade that offers a proper value:spend ratio. More so if you can manage to get the ASR version—they supply the Renntech version and can be had at half the price.
Sound character remains unchanged; there is just more of it. Probably 25% more sound, grunt and rumble. Gone is the lame/lazy raspiness of the exhaust unless you are flat out and over 4k RPM.
If this cost $1500, you would be disappointed. Given the price of replacement exhaust systems ($9000 or thereabouts), this really is just right.
I need to, and will, make some videos. Switching between stock valve operation and wide open (which you still can’t achieve by pressing the button in the cabin, mind you) takes a single button press.
Expectation Management: You won’t be awe struck. You will notice the difference, however.
Just picked up the ASR unit. Did you find installation instructions anywhere online that were helpful? Or a youtube video? I've looked but not with much success.
I must be blind but the video doesn't populate for me. Yes ASR makes the modules and licensed exclusively to RENNTech for selling in NA. So buying from the original source will be cheaper as a result. ASR refuse to sell directly to NA customers but if you use mail forwarding, it is doable. It is still cheaper than buying from RENNTech which shows how overpriced they are.
Last edited by W205C43PFL; Nov 19, 2025 at 09:08 AM.
I must be blind but the video doesn't populate for me. Yes ASR makes the modules and licensed exclusively to RENNTech for selling in NA. So buying from the original source will be cheaper as a result. ASR refuse to sell directly to NA customers but if you use mail forwarding, it is doable. It is still cheaper than buying from RENNTech which shows how overpriced they are.
I think the prior poster was being coy. Videos are below.
Sounds better in person, but you are able to hear how the flap causes congestion in the sound/tone. Removing the congestion carries over to driving and really just lets the truck sound as it should--without restriction.
Just picked up the ASR unit. Did you find installation instructions anywhere online that were helpful? Or a youtube video? I've looked but not with much success.
Videos have now been added.
As for installation, ASR included a QR code in my packaging. That QR brought you to a page of links to instructions on their website. If you don't have the QR and can't locate the page, let me know.
However, install wasn't too difficult at all.
1. Remove the trunk floor. Note that it doesn't just pull up. Ask me how I know. You have to pop off the plastic covers on the metal tie-down rings and remove bolts.
2. Locate the rubber grommet from trunk to underside. It's at 1 o'clock. Punch a hole in the unused portion of the grommet and feed the connectors through.
3. Crawl under truck. Locate connectors through grommet. Feed connectors towards each muffler. Best to route the cables in a way that prevents them from hanging free. Or from interfering with moving parts underneath.
4. Disconnect OE cable from valve actuators. Connect OE cables to female ASR cables. Connect male ASR cables to valve actuator.
5. Secure cables at actuators to ensure they don't have free play and are not resting on the pipes.
6. Secure module in or around battery. Ensure cables are snug.
7. Reinstall floor.
8. Fire it up.
FYI. Protective eyewear is a good call while under the truck. Ours had 2000 miles and had never seen rain at the time. It still shed gunk that enjoyed finding its way into my eyes.
Let us know what you think once you've got your installed.
I have my first G63 on order, so forgive me if this is a dumb question. But doesn’t using sport+ mode open the valves all the way anyway? I am coming from the BMW world, where the valves operate independently of drive mode (and is instead dependent on throttle input and RPM), but I was under the impression that the valve behavior on the G63 could be entirely controlled by the drive modes. I actually purchased an Akrapovic exhaust for my soon to be delivered G63 and was told by the manufacturer that there is no “Sound Kit” for the W464 (as there was for prior generations) since the exhaust relies on factory valve operation.
I have my first G63 on order, so forgive me if this is a dumb question. But doesn’t using sport+ mode open the valves all the way anyway? I am coming from the BMW world, where the valves operate independently of drive mode (and is instead dependent on throttle input and RPM), but I was under the impression that the valve behavior on the G63 could be entirely controlled by the drive modes. I actually purchased an Akrapovic exhaust for my soon to be delivered G63 and was told by the manufacturer that there is no “Sound Kit” for the W464 (as there was for prior generations) since the exhaust relies on factory valve operation.
not a dumb question at all. Sport+ mode yes it opens it fully but only if the RPMs are high, once you shift and RPMs are low again it closes back up. Yes it still opens wider than confort mode on idle but it is not anywhere close to fully open, more like 15%-25%? So sort of like the bmw you mentioned, but full disclaimer, there might be model year between changes so I am not fully sure if it is still true.
As for installation, ASR included a QR code in my packaging. That QR brought you to a page of links to instructions on their website. If you don't have the QR and can't locate the page, let me know.
However, install wasn't too difficult at all.
1. Remove the trunk floor. Note that it doesn't just pull up. Ask me how I know. You have to pop off the plastic covers on the metal tie-down rings and remove bolts.
2. Locate the rubber grommet from trunk to underside. It's at 1 o'clock. Punch a hole in the unused portion of the grommet and feed the connectors through.
3. Crawl under truck. Locate connectors through grommet. Feed connectors towards each muffler. Best to route the cables in a way that prevents them from hanging free. Or from interfering with moving parts underneath.
4. Disconnect OE cable from valve actuators. Connect OE cables to female ASR cables. Connect male ASR cables to valve actuator.
5. Secure cables at actuators to ensure they don't have free play and are not resting on the pipes.
6. Secure module in or around battery. Ensure cables are snug.
7. Reinstall floor.
8. Fire it up.
FYI. Protective eyewear is a good call while under the truck. Ours had 2000 miles and had never seen rain at the time. It still shed gunk that enjoyed finding its way into my eyes.
Let us know what you think once you've got your installed.
not a dumb question at all. Sport+ mode yes it opens it fully but only if the RPMs are high, once you shift and RPMs are low again it closes back up. Yes it still opens wider than confort mode on idle but it is not anywhere close to fully open, more like 15%-25%? So sort of like the bmw you mentioned, but full disclaimer, there might be model year between changes so I am not fully sure if it is still true.
Interesting. I wonder why Akrapovic determined the sound kit valve controller was necessary for the w464 exhaust but not the w465.
I'm at bit confused when you say that in sports+ mode that the exhaust flaps open fully only if the rpm's are high enough.
I drive my car all the time in sports+ mode with the stock exhaust button on and when turning my car off in the garage, the car is at idle and i believe with the pic i've provided below shows the exhaust flaps are fully open.
I'm at bit confused when you say that in sports+ mode that the exhaust flaps open fully only if the rpm's are high enough. I drive my car all the time in sports+ mode with the stock exhaust button on and when turning my car off in the garage, the car is at idle and i believe with the pic i've provided below shows the exhaust flaps are fully open.
I'm at bit confused when you say that in sports+ mode that the exhaust flaps open fully only if the rpm's are high enough.
I drive my car all the time in sports+ mode with the stock exhaust button on and when turning my car off in the garage, the car is at idle and i believe with the pic i've provided below shows the exhaust flaps are fully open.
Originally Posted by 366636
I'm at bit confused when you say that in sports+ mode that the exhaust flaps open fully only if the rpm's are high enough. I drive my car all the time in sports+ mode with the stock exhaust button on and when turning my car off in the garage, the car is at idle and i believe with the pic i've provided below shows the exhaust flaps are fully open.
Thanks for the image, I appreciate it. They might had changed the behaviour during the facelift or just later model years of the G-wagen hence why Akrapovic did what they did. In the past, idle is noticeably louder on idle with an EVM outside in sport+. Is this an OPF equipped exhaust? Thanks again for the insight, glad to be corrected and that no more EVM is necessary.
I forgot to ask, is the engine warm or this is cold start?
Sorry as i just realised that this thread is regarding a G63 as i have a pre facelift 2016 c63s coupe.
Anyway, to answer your question if this was a warm or cold start, pic was taken 4 days after my car was driven in sports + mode and car yet to be re-started.
My point here is that pre face lift cars in sports+ mode open their valves fully all of the time as well as at idle as that was how my car was last operated at before taken the pic.
Sorry as i just realised that this thread is regarding a G63 as i have a pre facelift 2016 c63s coupe.
Anyway, to answer your question if this was a warm or cold start, pic was taken 4 days after my car was driven in sports + mode and car yet to be re-started.
My point here is that pre face lift cars in sports+ mode open their valves fully all of the time as well as at idle as that was how my car was last operated at before taken the pic.
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