MV Agusta Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter #1
Hi there,

I have just purchased an Arrow Thunder in carbon fibre,
very happy with the looks and the fitment BUT I need to try and quieten it down a bit.
Its starting to attract the kind of attention I don't want, you can now here me well before you see me !
I have purchased another db killer so that I can have a play around modifying it without ruining the original one, if you know what I mean.
I have attached a couple of photos to give you an idea of what it looks like in standard form.
There are 3 rows of "5 holes" - 15 holes in total drilled in to its length.
If I cover up 2 rows of holes - 6 in total, by what ever means. would this cause any troublesome problems for the engine, eg. back pressure.
Before you start saying that I do not know what i'm talking about, I don't, that's why i'm asking for your expert knowledge
I look forward to your help.

brutale jockey
 

Attachments

·
Vendor
Joined
·
5,155 Posts
Hi there,

I have just purchased an Arrow Thunder in carbon fibre,
very happy with the looks and the fitment BUT I need to try and quieten it down a bit.
Its starting to attract the kind of attention I don't want, you can now here me well before you see me !
I have purchased another db killer so that I can have a play around modifying it without ruining the original one, if you know what I mean.
I have attached a couple of photos to give you an idea of what it looks like in standard form.
There are 3 rows of "5 holes" - 15 holes in total drilled in to its length.
If I cover up 2 rows of holes - 6 in total, by what ever means. would this cause any troublesome problems for the engine, eg. back pressure.
Before you start saying that I do not know what i'm talking about, I don't, that's why i'm asking for your expert knowledge
I look forward to your help.

brutale jockey
Have you a machine shop near you.Those baffles would be easy to make.or you could have the holes welded up.:)
 

·
Registered
Joined
·
51 Posts
Discussion Starter #5
Hi there,

I have not removed the original db killer, as the exhaust and spare db killer both turned up at the same time, I just thought they would both be identical.
I ordered the spare db killer from an official Arrow supplier and gave him the part number I got from the Arrow Italy website - spare parts for Arrow thunder exhausts.
I must admit that when I saw the "dome" welded on the end of the killer, I was surprised, I thought it would be straight through like the one you extracted from your Arrow thunder exhaust.
Any more info would be nice

brutale jockey
 

·
Registered
Joined
·
1,494 Posts
Hi there,

I have not removed the original db killer, as the exhaust and spare db killer both turned up at the same time, I just thought they would both be identical.
I ordered the spare db killer from an official Arrow supplier and gave him the part number I got from the Arrow Italy website - spare parts for Arrow thunder exhausts.
I must admit that when I saw the "dome" welded on the end of the killer, I was surprised, I thought it would be straight through like the one you extracted from your Arrow thunder exhaust.
Any more info would be nice

brutale jockey
The "dome" welded is pretty standard. Its the same on my MV Corse pipes. Just weld up some of the holes. Start with 1 row first.. the closest to the tail if you want to start somewhere?
 

·
Registered
Joined
·
14,209 Posts
?

So it looks like there are 3 different dB Killers

if your's with the 15 holes are too loud wrap a narrow strip of sheet metal around it and

secure with a hose clamp..... starting with the rear holes .....still too loud?

use a wider strip of sheet metal.....

ideally you'd want to stagger the blocked holes to disrupt the shock wave .....so you

have less back pressure......

Me ? my dB Killers are long gone.......no sound test/requirement in California

:drummer::drummer:

so ALL the yuppie twats on the phone or texting know I'm there

:stickpoke:stickpoke
 

·
Registered
Joined
·
51 Posts
Discussion Starter #8
Thanks for that Noel,

I have just told my other half that we are moving to California, great weather and NO sound tests !

That's a good idea about staggering the holes, thanks again

brutale jockey
 

·
Registered
Joined
·
14,209 Posts
?

Neil;
and everyone think of the pressure pulse as a line across the pipe......you want to break

this up mechanically if possible.....if you make 90° corners .....with the holes you're

getting the pulse edgewise not head on where the amplitude (pressure) is way higher

After thinking about it I think an angled cap would be better than a dome because it

makes the center of the pulse bounce around inside the can

and it doesn't increase back pressure....as long as the area of the exit doesn't get small

:)
 

·
Registered
Joined
·
465 Posts
Neil;
and everyone think of the pressure pulse as a line across the pipe......you want to break

this up mechanically if possible.....if you make 90° corners .....with the holes you're

getting the pulse edgewise not head on where the amplitude (pressure) is way higher

After thinking about it I think an angled cap would be better than a dome because it

makes the center of the pulse bounce around inside the can

and it doesn't increase back pressure....as long as the area of the exit doesn't get small

:)
Maybe rifle the bore of the can, or add a twist to the db killer to speed the pulses along as well.
 
1 - 10 of 10 Posts
Top