Making a muffler
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Re: Making a muffler
Now all the components and raw material are catalogued, the fixtures and prints are ready, etc. John Kuhn installed the exhaust, this is the final hookup. After oil cooler and some hoses are done, it’s time for a sound check.
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Re: Making a muffler
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU
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Re: Making a muffler
I think I found one topic that wasn't debated.Some x pipes are 2 pieces of 90 degree tubing with a section cut out and welded together.That would be a reduction of total volume at the x.Others are formed pieces welded together that increase volume at the x.Does the volume differences change the sound waves?
- midnightbluS10
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Re: Making a muffler
So you think you know more about their exhaust than they do and you've only seen it in a video while they've tested it and modified and tested, etc?ptuomov wrote: ↑Sun Jan 07, 2018 7:24 amLook at the poor fools designing F1 exhaust ports and headers. The idiots are using the same “anti-flow” infinity-pipe shape off the head in their exhaust. Fail!
https://youtu.be/Q9X-Xe3ueL0
If you're that good, why don't you model F1 cars over the phone or something? Since you can tell better than they can what their parts do just by looking at them? They would have no need for all those millions of dollars if they'd just hire you. Lol
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bigjoe1 wrote:By the way, I had a long talk with Harold(Brookshire) last year at the PRI show. We met at the airport and he told me everything he knew about everything.It was a nice visit. JOE SHERMAN RACING
Re: Making a muffler
Is this in response to me or naukkis79? For what it's worth, I was attempting sarcasm. I think the shape is fine, and the fact that F1 uses it makes me more confident that the shape is fine.midnightbluS10 wrote: ↑Fri Feb 16, 2018 11:14 amSo you think you know more about their exhaust than they do and you've only seen it in a video while they've tested it and modified and tested, etc?ptuomov wrote: ↑Sun Jan 07, 2018 7:24 amLook at the poor fools designing F1 exhaust ports and headers. The idiots are using the same “anti-flow” infinity-pipe shape off the head in their exhaust. Fail!
https://youtu.be/Q9X-Xe3ueL0
If you're that good, why don't you model F1 cars over the phone or something? Since you can tell better than they can what their parts do just by looking at them? They would have no need for all those millions of dollars if they'd just hire you. Lol
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU
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Re: Making a muffler
I don't know, but if I'd have to guess, I'd guess that both reduce noise but the x-pipe that has the smaller minimum cross-sectional area at the merge will reduce the noise more.RCJ wrote: ↑Fri Feb 16, 2018 10:46 am I think I found one topic that wasn't debated.Some x pipes are 2 pieces of 90 degree tubing with a section cut out and welded together.That would be a reduction of total volume at the x.Others are formed pieces welded together that increase volume at the x.Does the volume differences change the sound waves?
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU
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Re: Making a muffler
This doesn't really tell you much about the sound, but at least there's proof of life now!
https://photos.app.goo.gl/aLw7CcvO2UbR6QZx1
https://photos.app.goo.gl/aLw7CcvO2UbR6QZx1
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Re: Making a muffler
I don't have a high quality audio sample yet, but it's already clear that some thing have changed considerable.
Compared to the old "true dual" no cross-over 3" system with just two mufflers, the new dual 3.5" "infinity pipe" system is
- somewhat quieter
- firing sounds a lot more even at idle
- has none of the high frequency noise of the old system, no snap-crackle-pop
- has much lower and much softer "toned" sound
- sounds like a much larger engine, despite still being only a 5.0L motor
Soon we'll learn what it sounds during part throttle cruise and full throttle, high boost, high rpm acceleration. One of the main goals was to get rid of the low rpm cruise "drone".
Compared to the old "true dual" no cross-over 3" system with just two mufflers, the new dual 3.5" "infinity pipe" system is
- somewhat quieter
- firing sounds a lot more even at idle
- has none of the high frequency noise of the old system, no snap-crackle-pop
- has much lower and much softer "toned" sound
- sounds like a much larger engine, despite still being only a 5.0L motor
Soon we'll learn what it sounds during part throttle cruise and full throttle, high boost, high rpm acceleration. One of the main goals was to get rid of the low rpm cruise "drone".
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU
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Re: Making a muffler
Here’s a more informative exhaust sound clip, start at 1:20. It’ll be a little quieter with the intake side fully hooked up. Sounds like a really powerful car, but quite refined. I’m very happy, considering how difficult it is to make a dual 3.5” exhaust quiet.
https://youtu.be/qylNEtqyxHM
https://youtu.be/qylNEtqyxHM
Paradigms often shift without the clutch -- https://www.youtube.com/watch?v=cxn-LxwsrnU
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Re: Making a muffler
A rapid INcrease in cross section can also cut sharp noise. I think the mechanism is, velocity is lost when the flow has to expand into the larger cross section, and then energy is lost when it has to speed up again afterward.ptuomov wrote: ↑Fri Feb 16, 2018 11:31 amI don't know, but if I'd have to guess, I'd guess that both reduce noise but the x-pipe that has the smaller minimum cross-sectional area at the merge will reduce the noise more.RCJ wrote: ↑Fri Feb 16, 2018 10:46 am I think I found one topic that wasn't debated.Some x pipes are 2 pieces of 90 degree tubing with a section cut out and welded together.That would be a reduction of total volume at the x.Others are formed pieces welded together that increase volume at the x.Does the volume differences change the sound waves?
Interesting that OEM X-pipes are generally H stampings with a large cross sectional change.
Re: Making a muffler
The main reason why expansions cut on noise is not so much the mean flow velocity dropping but the expansion chamber muffling from acoustic theory and reflected waves cancelling.peejay wrote: ↑Mon Apr 09, 2018 6:40 amA rapid INcrease in cross section can also cut sharp noise. I think the mechanism is, velocity is lost when the flow has to expand into the larger cross section, and then energy is lost when it has to speed up again afterward.ptuomov wrote: ↑Fri Feb 16, 2018 11:31 amI don't know, but if I'd have to guess, I'd guess that both reduce noise but the x-pipe that has the smaller minimum cross-sectional area at the merge will reduce the noise more.RCJ wrote: ↑Fri Feb 16, 2018 10:46 am I think I found one topic that wasn't debated.Some x pipes are 2 pieces of 90 degree tubing with a section cut out and welded together.That would be a reduction of total volume at the x.Others are formed pieces welded together that increase volume at the x.Does the volume differences change the sound waves?
Interesting that OEM X-pipes are generally H stampings with a large cross sectional change.
Car factories are working to shave pennies and grams from exhaust systems bolted on cars that retail for $100k while trying to produce a sound that attracts that buyer of $100k cars. I am looking at the exhaust system on my 2018 E63S Wagon and it's not something that can be improved by mere mortals with the factory objective function and constraints.
In any case, what did you think about the twin-turbo 928 exhaust sound on that youtube.com video?
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Re: Making a muffler
I personally thought it sounded fabulous. Fantastic job.
If my 2.3 turbo can be that quiet, I'll be thrilled.
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Re: Making a muffler
Tantalizing! -So when do we see and hear a WOT launch and some red line up-shifts?
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Happy is he who can discover the cause of things.