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$50 C63S Exhaust Valve Mod: Force Valves Open 100% with AWE Simulators
With all of the ASR module talk lately, I wanted to find an easy way to get more sound out of the stock AMG Performance Exhaust. I purchased a set of AWE Exhaust Valve Simulators last year (for a different project) and it just occurred to me that these can be used to force open the stock electronic exhaust valves without setting off a fault or putting the car in Limp mode. That means the exhaust valves are 100% open 100% of the time, it doesn't matter whether you're in Comfort mode or Race mode. This also means during startups the valves are completely open as well.
For those that don't already know, the OEM exhaust valve programming only opens the exhaust valves to about 50% at idle, and only opens 100% when under load, high RPM's, and briefly when revving in neutral. This is obviously something AMG programmed for noise regulation and pedestrian comfort. With this $50 mod, the exhaust valves are always 100% open and always loud. You get way more exhaust volume and bass down low in the RPM's and at idle, and even louder, more frequent pops and cracks! Even though the OEM exhaust valve button will no longer control to two rear exhaust valves, I still highly recommend keeping the exhaust button ON because it allows the valve in the H-Pipe to open more aggressively in Sport+ and Race mode.
It's hard to capture the sound on video, but it's a very easy mod that only takes 10-15 minutes and you can always revert back to stock if needed.
1. Park and lock vehicle. Determine the range of the keys (pro-tip: I put the keys in a Faraday cage to easily block the signals):
- Step away from the vehicle and attempt to lock or unlock the car using the key fob.
- Continue to move away until the car no longer responds to the key. This is the range of the key.
- ALL keys must be completely outside this range. If a key remains within range of the car, the vehicle may respond to the key and awaken unexpectedly, which could result in a stored fault and reduced engine power.
2. Leave the vehicle undisturbed for 10 minutes. This allows adequate time for the electronics to go to sleep.
3. Unplug the passenger side exhaust valve.
4. Plug in the AWE Exhaust Valve Simulator and zip-tie the plug away from the exhaust.
5. Repeat the same on the driver side exhaust valve.
6. Put electrical tape over both open exhaust valve plugs to keep out moisture, dirt, etc.
Nice write up. As much as I would love to control the system with the button, I rarely leave it in quiet mode and it’s a hard pill to swallow $600 for a simple mod.
Any my opportunity to get a video of you just cruising at idle in a parking lot or something? Agree with you though, hard to get a true sense of the sound in video.
So since you’re in Austin come by and let me hear it in person
You ever around central Austin? I need to hear this in person so I know if I want to spend the $500 for the ASR module or if this would do!
Yes, I’m local in Westlake! We can meet up and compare. I’m still going to purchase an ASR module because I want to be able to switch back to closed when needed (around the neighborhood, with non-car people in the car, etc.).
Michael - thanks for the tip on disabling the key signals. I grabbed that first part of the directions from Dinan’s piggy install, I just don’t trust the car won’t wake up somehow during the install... maybe it’s my OCD
Yes, I’m local in Westlake! We can meet up and compare. I’m still going to purchase an ASR module because I want to be able to switch back to closed when needed (around the neighborhood, with non-car people in the car, etc.).
Michael - thanks for the tip on disabling the key signals. I grabbed that first part of the directions from Dinan’s piggy install, I just don’t trust the car won’t wake up somehow during the install... maybe it’s my OCD
I am Mopac/183 for work. Let me know if you're ever in the area.
Interesting. Thanks for posting. Seems like a $53 version of the BMW golf tee mod Not too bad.
Yup, definitely interesting... Ending up going with the $300 ASR module though...get remote switch for it and I don't like the idea of having tape, zip ties, or potentially open components on the car... Just OCD like that. But for those that want a poor-man's alternative (not in a derogatory way), this is a great option.
Okay! Order and should be here in couple days. I let you know how it goes! Thanks for trying this out. I thought about it a long time age (getting just the sensors plugs) but assumed it would have been default closed.
is case anyone were wondering, the SKU 1310-11018 fits most vehicles, so its not just for Audi, VW or whatever. On AWE's site, all cars is listed that is compatible.
Hey, thanks for this!
I was hoping for a simple/cheap mod to breathe some life into my car and this did it!
$50 later (well, $80 since I was impatient and did 2-day shipping), I got these things installed in about 30 minutes...read more to find out why it took so long...
As others have said this is mod is mainly to give more sound during "normal" driving and is very much noticeable or "louder" on the low end since the valves never close, but the WOT sound doesn't change at all (since WOT opens the flaps 100% and with these simulators we're always 100% open). I am still happy I don't have to gun it from a stop to hear the exhaust better, this makes the car sound more" burly" as you pull away.
As someone who hasn't really worked on cars in many, many years (and never on MB's)... I will admit I had a heck of a time figuring out how to simply disconnect the dang plugs!
Here's a tip for anyone in my (embarrassing) situation:
There's a gray "clip" on the connector, you need to pull it AWAY from the socket until you hear a click. It takes some effort. This will disconnect/unlock the plug and you can then pull it out.
Here's the clip, and if you're looking it at it this way, use a stubby screwdriver or something and pull to the right to unlock:
You can't quiet down the car anymore but just use your foot instead. Very worth it for those that wan't a bit more sound on the low/mid range without aftermarket exhaust! Thanks!
You don’t need keep keys away from vehicle, just quickly click twice on lock button on keyfob will disable keyfob signals transmitter.
Hey mate whats gonna happen if you did not disable the key fob signal transmitter? engine failure? also, when you install the simulator the the exhaust button is not ON all the time? I mean you can still turn it on or off .Thank you
Hey mate whats gonna happen if you did not disable the key fob signal transmitter? engine failure? also, when you install the simulator the the exhaust button is not ON all the time? I mean you can still turn it on or off .Thank you
I didn't disable the key fob signal transmitter, just put it about 20 feet away.
Simulators will have no effect on the exhaust button... it will continue to turn on and off as usual... but it actually won't DO anything since the valves are locked open.
I didn't disable the key fob signal transmitter, just put it about 20 feet away.
Simulators will have no effect on the exhaust button... it will continue to turn on and off as usual... but it actually won't DO anything since the valves are locked open.
Can you tell the difference with or without the simulator? Either 20 feet away or push the lock button two times is okay?
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
Not too bad. 
