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So I'm currently exploring ways to potentially increase the sound of the exhaust without going overboard (resonator and/or muffler delete).
I'm not sure if this has been done before, but my idea is to remove the valves circled in red (my car didn't come with the active exhaust, therefore I have no button to switch it anyway) and then block the exhaust path circled in green, effectively allowing more energy to go through the pipe, rather than dissipate in the muffler chamber.
Would be keen to hear your thoughts and feedback about whether this would actually work.
Interesting idea.
I for one would like to know the exact paths and relative volumes of the exhaust gasses going through the various pipes and muffler chambers, with and without the valves open, as I really can't tell what is going on just by looking at that cut away diagram.
The other, but more labour intensive idea I had, was to cut out the perforated pipes in the middle section and replace with solid straight pipes. Very popular mod with BMWs
So I bit the bullet and decided to go down the more difficult route. Armed with the cutaway image, I went to a fab guy who's well known in the BMW community.
First, we took the muffler off the car and opened it up for surgery...
We were both surprised that it was hollow - no muffler packaging!
Next was cutting out the hexagonal 'resonators'. It's basically a perforated pipe that's wrapped in glass fibre and encased in these hex chambers...
Measuring up some stainless steel pipes to weld in place of the resonators - around 2 inches in diameter:
In order to get to the underside of the pipe without opening up the other side, my guy used a trick where a section of the pipe is removed on either end. This section is then welded back on:
MIG welds will never be pretty, but they're solid welds. Even though it's stainless steel, will never rust, and will never be seen since it's enclosed, he still decided to paint the pipes - now that's attention to detail!
Surgery now complete, time to zip her up - TIG welded with stainless filler rod. No rust to worry about and no ugly MIG welds with slag everywhere!
Mounted it back on, started it up and I was speechless... I'll get some videos up soon when the weather clears up here, but if you're thinking about doing this mod, be warned, the change is NOT subtle.
Up to 2.5k rpm, it's still civilised. Beyond that, she begins to SCREAM. The overall notes/tone remain somewhat similar, but the noise/sound is amplified fivefold.
If I was to sum up the change in sound in one word, it would be 'crisper'.
To me, the stock exhaust sounded 'hollow' and kind of fake. This mod has cleaned up the tone to have a much more 'natural' sound and has resulted in a higher pitch; closer to exotic, which is exactly what I wanted. I'm not a big fan of the low, bassy rumble.
Would I recommend this mod? The answer is a resounding YES.
Congratulations and especially on getting the “Official UNHINGD Seal of Approval.” The standard by which modifiers of all shapes and sizes just dream of. It’s the “Good Housekeeping Seal of Approval” equivalent.
Well done!
P.S. Now all you’ll need is the “Unofficial ITSMEJOSHY Seal of Approval” and then you’ll be all set!
Hey Dpark, just as a point of clarity for me in reference to your original post, aren't those valves with the vacuum lines running to them part of the "active exhaust" system? My understanding is that what differentiates "active exhaust" from "switchable active exhaust" is that switchable indicates the presence of a button on the console where the operator can control the valves whereas non-switchable (for want of a better description) means the valves are controlled by the ECU. I assume there exist F-Types without the valves at all, but not sure.
Question: Are you permanently blocking the vacuum valves so that you're running all loud all the time?
Nuther question: With valves open how much exhaust do you think is still being muffled?
BTW I've de-activated the valves on mine by simply plugging the valves themselves and the lines leading to them; very quick and painless to put things back to normal.
There's a point at around 3krpm where it drones a smidge. Solution is to avoid that rev range for long periods of time. Me personally, it was absolutely fine since our speed limit on highways is 110km/h and I rarely drive long-distance.
Originally Posted by fujicoupe
Hey Dpark, just as a point of clarity for me in reference to your original post, aren't those valves with the vacuum lines running to them part of the "active exhaust" system? My understanding is that what differentiates "active exhaust" from "switchable active exhaust" is that switchable indicates the presence of a button on the console where the operator can control the valves whereas non-switchable (for want of a better description) means the valves are controlled by the ECU. I assume there exist F-Types without the valves at all, but not sure.
Question: Are you permanently blocking the vacuum valves so that you're running all loud all the time?
Nuther question: With valves open how much exhaust do you think is still being muffled?
BTW I've de-activated the valves on mine by simply plugging the valves themselves and the lines leading to them; very quick and painless to put things back to normal.
Hi Fujicoupe, you're spot on regarding the active vs switchable active exhaust. My car had the base muffler - no valves to open/close, so no vacuum lines and of course no button. I bought the active exhaust off a wrecked F Type and the valves are open 24/7.
Regarding how much is still being muffled, I'm no physicist, but logic states that the gases will flow the path of least resistance at high velocity, i.e., straight through to the exit. When I looked inside the 'j pipe' that leads into the muffler chamber, it's actually a very acute right angle and the way the pipes are laid out, it almost looks like it discourages flow through this route.
Very different to say the inside of an x-pipe, where the paths are open to both sides once gases reach the x section. I've tried to replicate what I saw in paint, so you'll kinda get the idea:
Notice the area circled in red - in particular how the lines don't match up - and imagine gas flowing through. You can see that there would be a reluctance for it to turn hard right.
Now, if the valves were closed and forced the exhaust to travel in the opposite direction, it'll be encouraged to find its way out the side, rather than upstream, where it would be countering the force of the exhaust traveling down.
There's a point at around 3krpm where it drones a smidge. Solution is to avoid that rev range for long periods of time. Me personally, it was absolutely fine since our speed limit on highways is 110km/h and I rarely drive long-distance.
Hi Fujicoupe, you're spot on regarding the active vs switchable active exhaust. My car had the base muffler - no valves to open/close, so no vacuum lines and of course no button. I bought the active exhaust off a wrecked F Type and the valves are open 24/7.
Regarding how much is still being muffled, I'm no physicist, but logic states that the gases will flow the path of least resistance at high velocity, i.e., straight through to the exit. When I looked inside the 'j pipe' that leads into the muffler chamber, it's actually a very acute right angle and the way the pipes are laid out, it almost looks like it discourages flow through this route.
Very different to say the inside of an x-pipe, where the paths are open to both sides once gases reach the x section. I've tried to replicate what I saw in paint, so you'll kinda get the idea:
Notice the area circled in red - in particular how the lines don't match up - and imagine gas flowing through. You can see that there would be a reluctance for it to turn hard right.
Now, if the valves were closed and forced the exhaust to travel in the opposite direction, it'll be encouraged to find its way out the side, rather than upstream, where it would be countering the force of the exhaust traveling down.
Hope this kind of helps
Thanks for taking the time to expound on this. Just a thought: It would seem easy enough to replace the existing vacuum valves with a pair of electrically controlled ones, giving you complete control of how much exhaust you are diverting to the main chamber (?). Or not.
Thanks for taking the time to expound on this. Just a thought: It would seem easy enough to replace the existing vacuum valves with a pair of electrically controlled ones, giving you complete control of how much exhaust you are diverting to the main chamber (?). Or not.
wow this looks awesome! so glad to see this, I have an S with the switchable active exhaust and would love a bit more noise down the road, I heard a res delete and to me it sounded awful, and the muffler delete sounded great But I can't live without my valves. Please, please, please post as many videos as humanly possible. I would do this today if My exhaust valves haven't failed 5 times and had to have the whole catback replaced under warranty. And I know this would 100% void my exhaust warranty.
wow this looks awesome! so glad to see this, I have an S with the switchable active exhaust and would love a bit more noise down the road, I heard a res delete and to me it sounded awful, and the muffler delete sounded great But I can't live without my valves. Please, please, please post as many videos as humanly possible. I would do this today if My exhaust valves haven't failed 5 times and had to have the whole catback replaced under warranty. And I know this would 100% void my exhaust warranty.
Do you live in a seaside community or drive in salted roads? That would be my only explanation for so many consecutive failures.
wow this looks awesome! so glad to see this, I have an S with the switchable active exhaust and would love a bit more noise down the road, I heard a res delete and to me it sounded awful, and the muffler delete sounded great But I can't live without my valves. Please, please, please post as many videos as humanly possible. I would do this today if My exhaust valves haven't failed 5 times and had to have the whole catback replaced under warranty. And I know this would 100% void my exhaust warranty.
I thought typically changing the muffler and exhaust tips typically do not void warranties?
Modifying V6 active exhaust
