what about car mufflers?

[cat]

What's wrong with using car mufflers like this? Not enough volume compared to something like this Laser can?

[keithcross]

I suppose they might be alright, but suspect they would be to restrictive. Also it may be difficut to get the right size input pipe.

Keith

[cat]

I suppose they might be alright, but suspect they would be to restrictive. Also it may be difficut to get the right size input pipe.
Keith

Well, I suppose what it really comes down to is that I'd like to know what the insides of the BSM and the GPR and the M4 are like.
So my question was wrong.

I'd guess that the exhausts for the 660 are something like that Laser can in the picture. They're too quiet to be straight-through. The differences in the can diameters, the amount and density of the packing, and how the pressure gets out would be what makes them sound different.

Unless the back part of that car muffler is different from the front shown by the cutaway, it's the least restrictive type, and the loudest - the "classic" straight-through type. The perforated pipe is connected to the inlet and the exit and the entire space around it is filled with packing.

Generally, the quieter systems are more restrictive; the more baffling and packing there is for the pressure wave to get through, the more the sound is reduced and the slower the exhaust pressure gets out.

Forcing all the pressure through packing and/or convoluted baffling is not good for power. So a typical feature of the current designs is a removable 'dB killer'; with it in, the pressure wave, having passed through some packing to dampen [?] it, expands into a more open space and the exit hole is not line with the pressure waves so the waves are again broken up - like in the cutaway of the Laser muffler. When the 'dB killer' is taken out, the exit hole is in line with the pressure wave, so it gets out quicker.

It's difficult to know what different exhausts are doing to the torque curve without having it on a dyno, and rejetting as necessary - which gets expensive.

My impression - from what I've read on this forum - is that the M4 produces the biggest power difference.

The inlet tube... they vary, those VOLT exhausts, there's a wide range, inlet tubes are 3", 2.5", 2.25". The Baghira connector pipe is 50mm, I think - 2". What you do there is flare out the connector tube, or weld on a flared section to match the can.

[phlat65]

you could radially slot the 2.25 pipe on 4 sides, then weld it back up and weld it to the head pipe.

when I did my dual system, I ran 1.5 inch pipe from each head pipe to each Ducati can, which have a 2 inch inlet, I reduced the inlet with the above method. the system flows WAY better than stock, and is quiet.I have a Fast By Ferraci full carbon race can, and I don't feel much if any performance difference between the two systems. the bike still pulls the same 2nd gear wheelies, with no change in effort. I actually think the tourque is better with the twin quiet system.

BTW, I got the Ducati cans on e-bay, never been run, for $25.00 plus shipping.

[cat]

you could radially slot the 2.25 pipe on 4 sides, then weld it back up and weld it to the head pipe.

when I did my dual system, I ran 1.5 inch pipe from each head pipe to each Ducati can, which have a 2 inch inlet, I reduced the inlet with the above method. the system flows WAY better than stock, and is quiet.I have a Fast By Ferraci full carbon race can, and I don't feel much if any performance difference between the two systems. the bike still pulls the same 2nd gear wheelies, with no change in effort. I actually think the tourque is better with the twin quiet system.

BTW, I got the Ducati cans on e-bay, never been run, for $25.00 plus shipping.

waY to go! <sigh> e-bay's great, just not so useful here because you'd be trusting someone/ usually not an online vendor to ship something, and paypal has never done SA.

Fast by Ferraci sounds so exotic

Your second gear wheelies - have you changed back to your 14-tooth sprocket?

[phlat65]

yes, I went back to stock gearing for the winter commuting, it will still go vert in 2nd, you just have to get it just right.

[hb7]

M4 for Skorpion is an 18inch oval can with a 2 inch inlet straight through..
no restriction. It is ~10lbs lighter than the stock or so....
It is loud....Nothing special about it. Any muffler should work
fine. Considering the cost of an M4 $300USD ....a car muffler is worth adapting....and not that hard for a muffler shop to do.