[Against Reality]

Hello guys , so after almost a month of having the exhaust on i have noticed a sound that i dont really like , it starts on higher rpms and it sounds like the bike has less flow , kind of raspy sound.
I also heard it on a video on youtube , guy with same exhaust has the same raspy sound
Does anyone know why is that?
If this is how it properly sounds i guess ill change
If anyone else has the same sound please let me know

 

[Against Reality]

Check this video , skip it at 1:08 and you will understand exactly what sound im talking about.

 

[MK3Brent]

Check this video , skip it at 1:08 and View attachment 173630

 

[Against Reality]

Thanks a lot 😁

 

[Emporer Zurg]

Hi,

I've had problems with the dB killer on my HP5 exhaust - how's yours doing in the HP3?

I think the HP5 is supposed to be much quieter than the HP3 - 99dB vs 102dB according to Dominator's video.Yamaha MT-09 2021 💥 Full Dominator Exhaust 🔥 Sound Test & Dyno 🔊 Pure Sound 🎧 HQ Sound 🇵🇱 ⚡ FZ-09 - YouTube
3dB is a lot but I still think the HP5 is too loud without the dB killer (and so do the neighbours), so I guess it's no surprise you want the HP3 to be quieter.

My dB killer had a rattle on the overrun - I could hear a metal on metal rattle that only appears with the dB killer, not without, and only when slowing down to traffic lights etc. I also got a lot more decel pops and up-change bangs with it in, and almost none with it removed. This is because it was not well made so it was not a good fit. So I wonder how yours is?

Hope it has worked out for you.

 

[Emporer Zurg]

With the silencer on, it's bordeline tolerable. And you also lose about 5 hp.
If I knew how loud it was, I would have gotten the one with the extra can in the mid pipe.

Hi Dante,

I have noticed a slight loss of response with the dB killer in but it's not significant. There's just a touch more vibration too. Do you know where the 5HP loss data comes from? I'd like to know more, especially if there's any dyno runs.

Thanks!

 

[Dante]

Hi Dante,

I have noticed a slight loss of response with the dB killer in but it's not significant. There's just a touch more vibration too. Do you know where the 5HP loss data comes from? I'd like to know more, especially if there's any dyno runs.

Thanks!

It was at top rpms. I don't have the dyno run with the silencer available however.

 

[Emporer Zurg]

Thanks. I think I feel a very slight loss in throttle response from about 4k up so that would mean a little less torque because of the backpressure created by a 42mm outlet after a 46mm perforated muffler core and a 48mm collector pipe. I can't say I noticed any top end loss - it still hits the speed limiter and feels like there's more to go ;-) It didn't create any noticeable flat spots. It is much quieter - my guess is about halfway between stock and no dB killer so maybe around -3dB.

While the Dominator could be 5 hp loss in a worst case I guess, other dB killers have been tested thanks to the awesome Vcyclenut.

As far as I can tell the Leo Vince dB killer goes before the muffler and into the muffler from the end of collector pipe. DBKILLER #1861-1586 | LeoVince so it's a different beast to Dominator's, but somewhat similar to another dB killer I'm experimenting with.

Vcyclenut tested the Leo Vince with and without dB killer and saw only 1hp loss, and the dB loss was mostly at idle "With no DB killer 70.4db @ idle 113.2 during dyno run. With DB killer [email protected] idle 112.2 during dyno run."

Leo Vince testing - FLASHED BY VCYCLENUT

He also tested the Arrow dB killer - that exhaust is very similar to Dominator's, as is the dB killer. That shows a 3.7 hp loss Arrow exhuast testing - FLASHED BY VCYCLENUT and " makes a very noticeable difference in sound level".

 

[Dante]

Out of curiosity I emailed Dominator to ask them if they sell the mid pipe with the silencer can separately.
They answered almost immediately that they do, but it costs 210 euros plus shipping, so it seems a lot to me.
I might ask some exhaust makers here ,if they can modify mine by cutting it and adding a can and then welding it. I believe it will be cheaper.
I don't think that the bike will need to be retuned with just this change too.

 

[Dante]

@vcyclenut I see that you tried adding the Dominator mid pipe to another exhaust. Does it reduce noise noticably? Do you think it's worth adding it?
I want to remove the DB killer to gain the 5hp that the bike loses from it, but because it's too loud like this, I want to add the mid silencer can to compensate for the db killer. Think it's possible?

 

[vcyclenut]

@vcyclenut I see that you tried adding the Dominator mid pipe to another exhaust. Does it reduce noise noticably? Do you think it's worth adding it?
I want to remove the DB killer to gain the 5hp that the bike loses from it, but because it's too loud like this, I want to add the mid silencer can to compensate for the db killer. Think it's possible?

I didnt add it to a different exhaust I added it to the GP3 dominator exhaust

im not a dealer for dominator and only can speak of what I tested, it did reduce noise noticeably, if your trying to reduce the noise level it is worth it to me

 

[Emporer Zurg]

It'd probably be simpler to use a dB killer like the Leo Vince as a replacement for the Dominator one - something similar costs US$7 here. And you could do both I'm not happy with the Dominator one either, certainly in stock form.

The cheap ones that need modifying:

The Leo Vince design:

 

[Dante]

I didnt add it to a different exhaust I added it to the GP3 dominator exhaust

im not a dealer for dominator and only can speak of what I tested, it did reduce noise noticeably, if your trying to reduce the noise level it is worth it to me

Was the noise tolerable with that setup (Mid pipe+GP3 with no DB killer)?

It'd probably be simpler to use a dB killer like the Leo Vince as a replacement for the Dominator one - something similar costs US$7 here. And you could do both I'm not happy with the Dominator one either, certainly in stock form.

The cheap ones that need modifying:

View attachment 174402

The Leo Vince design:

View attachment 174403

If that reduces noise without affecting performance, yes I believe I could start with that.

The dominator DB killer reduces the can's exhaust diameter and I think that's why it reduces performance. It limits the exhausts flow.

 

[Emporer Zurg]

Was the noise tolerable with that setup (Mid pipe+GP3 with no DB killer)?


If that reduces noise without affecting performance, yes I believe I could start with that.

The dominator DB killer reduces the can's exhaust diameter and I think that's why it reduces performance. It limits the exhausts flow.

According to Dominator's site, the mid muffler reduces noise by 1 dB and the db killer is 2 to 3 dB. 1 dB is noticeable - a digital volume control usually steps 0.3dB or 0.5dB - so 1dB is appreciable.

The diameter restriction of the outlet is part of the reason - also length. All other things being equal, a pipe will flow 41% more if you cut it's length in half - an exponential relationship. 1.41 x 1.41 = 2. Cut its length and you raise its resonant frequency and the ability to block noise. Longer = quieter = less flow in this case.

I want to try a slash cut on the dB killer. If I cut a diagonal end on the pipe, I can create an ellipse with the same cross sectional area as the main exhaust pipe - 48mm. This means measuring back 35mm from the end and cutting diagonally to the original length. This will increase flow but also noise. If I add an LV type db killer too, I hope to get roughly the same volume of noise but with better flow at high rpm. Theoretically

 

[Emporer Zurg]

Hey Dante,
Just tried the LV imitation - works very well as a replacement for the Dominator - throttle feels a little more lively esp at 5k going into 6k when the party starts. Sounds better - it is about the same at idle but noise picks up with throttle much more so it is louder on the highway and blasting up a mountain road. It also sounds more bassy - more lion and less hornet than the Dominator db killer. Definitely worth a try to see if you like it. They are available on Aliexpress and Ebay if you cannot source one locally.


I cut 9mm off the mounting ring and cut the end cap off, like this:

 

[Emporer Zurg]

My experiments with db killers is done at last - the one above is the best. It's not the quietest but offers low enough noise for trickling through the village near idle speed, and yet gives a great bassy sound and, most importantly, good throttle response when riding.

I tried cutting down the Dominator and the results were reliably predictable. Shorter pipe, less restriction, more noise. The slash cut mixed the tone. The shortest length is now 60mm and the longest is 90mm.