Any exhaust specialists that can advise...?

[Mr Hammers]

So, i bought new cans for the Triple, and posted about them here.

Now, as good as they look, and as good as they sound, they are unbearably loud, even with the baffles in.

I called SP Engineering today and spoke about it with a woman there. She said in the past others having the same issue tried blocking the holes around the main outlet pipe. So when i got home, i did just that;

https://www.planetash.net/bcf/cans/triplebaffles.jpg

Double nutted the bolts and peened the ends so i don't end up having to remove the main pipe if a nut comes off. It is slightly quieter now, but still too loud for my liking.

https://www.planetash.net/bcf/cans/triplebafflesend.jpg

So, i was thinking about modifying the existing baffle to try and dampen down the noise a bit, or at least take the 'crack' out of it.

I know virtually nothing about cans and the physics of them, but i was wondering if something like this would work in bringing the volume somewhere between these cans and the stock ones.

A is the baffle, B is baffle packing, and C is a round plate that would be welded to the end of the baffle tube.

https://www.planetash.net/bcf/cans/triplecanplate.jpg

I did try some baffle packing in them left over from another job, and it seemed to dampen it quite well, but that was just temporarily wrapped around the tube and shoved in. Obviously during normal riding it would just end up working it's way down into the cans without a plate and/or some wire or mesh around the packing to hold it in place.

I don't mind losing the supposed bhp gains they bring, if it means i don't wake up half the neighbourhood every morning at 7am.

My question is: would this be a good way to do it, or is there another way? Like extending or shortening the baffle tube, and/or drilling holes in it then wrapping in baffle packing to disperse the sound..?

Hoping someone who knows the ways of these things can give us some helpful advice.

Cheers!
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[Fisty]

With gaping holes like that they are never going to be quiet.

Buy some quieter cans.
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TL1000R | Hayabusa | ZXR400 | TL1000S | Bandit 400 V
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[Mr Hammers]

[Sister Sledge]

Are the cans actually road legal?
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CCM 404 DS

[Mr Hammers]

No. The XLS versions are, they're about 50mm longer. I would've gone for those but they stick out beyond the tail light and look a bit daft.
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A Guide To Powerbands

[RhynoCZ]

Not the best design. What you want, and I did myself, is a pipe with closed of end and holes drilled into the pipe along side. That way the ''noise'' has to travel further distance and bounce of the inner pipe before it gets through those holes and out back. With the pipe fully open the noise reduction is negligible, unless that is what you want to achieve, stupidly loud let appearing road legal at the same time.

Like so,

https://www.megalevnepneu.cz/fotomp/783.18.37.jpg
https://img.skutry-levne.cz/41d48e526f04e6b742c5b4e32b09b17ef1a53098/thickbox/vlozka-db-killer-turbo-kit-maxi-skutr.jpg
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[stinkwheel]

You could try sticking another (minimalist and fairly wide) removable baffle in from the other end. So the ends of the two baffles overlap. Then you'll have a kind of z-flow effect.

In fairness, the "baffle" seems very straight meaning the gas is probably passing right through the end can and out of the end without slowing down in the middle to expand. Any effective silencer baffles I've seen have a bit of a dog-leg in them.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Robby]

For a baffle to be effective it should do two things:

1. Increase the effective length of the exhaust system.
This is done by forcing the exhaust gas to change direction, or entirely reverse direction. A standard exhaust on a bike or a car is a fairly complex shape inside, more like a maze.

2. Force the gas through some kind of restriction.
This is usually baffle packing material, although it can also be a mesh or a catalytic converter. It works best if you can force the gas through the baffle packing material more than once. This is done by blocking up the inside of the baffle, but also putting a ring around the outside of the baffle so exhaust gas can't just go around the outside of it.

Can you buy proper db-killers? Making baffles that work at home is a fairly involved process, lots of trial and error. I only did it because no-one currently makes quiet silencers for one of my bikes.

[MarJay]

It does beg the question, if they are too loud why fit them? They LOOK loud...
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[pig hog]

Just wear ear plugs?
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'13 Yamaha XJ6N '15 Daytona 675R / '16 MT-07 dead / '17 MT-07 / '18 MT-10

[MarJay]

Also, without a remap this'll ruin the fuelling...
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[RhynoCZ]

[redeem ouzzer]

DB killers work but kill top end. My racebike made more power with the stock can (whisper quiet) than it did with a straight through can with a dB killer shoved in the end.
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Be a REAL MAN!

[MarJay]

This is why I went with the Arrow low boy exhaust. It's noisy but not offensive. I then had the bike re-mapped and it's awesome now.

My old Daytona 955i made 90bhp with a baffle, and 115bhp without... THAT is how bad dB killers can be.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[RhynoCZ]

Yes, without the R&D and knowledge it is a guessing game.

I also noticed my engine ran cooler without the dB killer, but I've done no measurements (air-cooled four stoke). It would be only logical though.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[Bhud]

A stopped-up DB killer will make things a lot quieter, but will also most likely affect both valve overlap and exhaust excavation rate, and thus the performance of the engine. The only way to know how, or how much, is to measure the power output with it in and out. But who can be bothered with that? It's easier to just take it out when you want to play, and put it back in when you don't want to attract unwelcome attention.

[stevo as b4]

If you have a multi chambered long race can type silencer with a sensible/ same as the collector pipe size baffle, then they can be quiet enough to be tolerable and acceptable. It does also depend on the material of the silencer and the thickness of the shell and how it's constructed. Sometimes carbon cans are quieter as they don't resonate so much as say stainless etc. But then again they can make the sound deeper which might feel like it's louder.

But the problem is that people want silly shorty/cut down cans, and you can't have short and quiet it doesn't compute.

Also as Blue said Db killers are nasty things and an afterthought, mainly to allow trackside noise testing limits to be met so you don't get sent home. They almost always produce less power than the standard reflective silencer and don't take peoples word for it, go to BSD racing's website and look at the case studies on different bikes and exhausts.

Also be prepared to make serious fueling changes especially on very modern EFI bikes for any exhaust modification, as they nearly always need alot of work to make them fuel how the engine designer would have intended.

[stevo as b4]

If all else fails you could always fit a turbo, as that'll take a load of sound energy out of the exhaust system, and probably make it a bit quieter than std at low Revs.

[recman]

[biker7]

Too loud for you, or others as well? If just the former, I second earplugs (tip - Blue Tac works well!) Personally, I like loud. Maybe block the hidden end by boring a hole and bolting on an angle bracket and repair washer. Don't get rid - baffles are just blockages and easy to regulate.
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Swansea area
Fat Bob (2019)

[Mr Hammers]

Cheers for all the input guys, much appreciated.

Well, the ride with the holes plugged this morning was a lot more civilised. Made a bigger difference than i'd expected. Also gave me hope for taking a bit more of the edge off the sound level by way of modding the baffle. Using the sound app on the phone, the sound levels (after plugging the holes) are down to about 80 when idling, and rising to 100 when revving the balls off it. If i can get it down to around the low 90s i'll be happy.

Got a week off next week, so i think i'll experiment with various baffle types and placement, in fact quite looking forward to it as it could be quite interesting.

[Tdibs]

Cant claim any useful knowledge on the subject, but having used a couple, I found this design the most effective and quieting down the can enough to not be obnoxious.

https://www.ducatiforum.co.uk/attachments/duc-scorpion-baffles-jpg.47197/

So something like welding a cap on the end and perforating the tube.

https://puu.sh/CZqtt.jpg

Then most likely take it for a remap.
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[recman]

[Mr Hammers]

[recman]