If a bike makes 135HP at 10000 rpm with two mufflers, but a modified VW with double the bike's displacement makes 60HP at 4000 rpm, would it need one bike muffler or two?
If a UFO came down from space and zapped you with a red laser and then a green one which one would hurt more...
its more than the muffler.... and one should surfice
Then tell me about the "more" part, that's what I'm after.
its the system as a whole mainly its from the heads back.
So assuming the VW's 4 into 1 header is more restrictive, including the tight bend into the muffler, does that indeed mean that one will suFfice?
You don't normally see VW exhaust systems with more than one muffler. There are 4-into-1 systems that then branch off to a muffler at each side, but
they have no advantage over 1 muffler. 2 mufflers only work when they are in series, not in parallel.
A motorbike muffler ought to be more efficient and quieter than, say a fibreglass 'hot dog' style single muffler, and is around the same size.
The RPM range of VW engines is a lot less than motorbike engines. Bike mufflers are designed to quieten the 10,000+ rpm screams that VW engines will
never produce. How quiet are bike mufflers up to, say, 5000 rpm, which is what the VW engine will do?
What sort of VW engine are you planning to put a bike muffler on? Stocker, hot street, race??
If I recall correctly, Jeff Unwin used a bike muffler on the 2213cc(?)
hellbug back in the early 90's(?) when he ren a Raleigh Raceway near Nambucca Heads.
Car was still fast, even with a loose intake manifold, and sounded awesome.
I know of a couple of hot beetles that are getting around with bike muffler's on 'em... Gracey (on here) being one of em... and they're all getting
good results.
The local muffler dude who's also into racing (BMW's rather than VW's unfortunately) was telling me that a single, superbike style disassembleable
(is that even a word?) muffler would work brilliantly on a VW...
Pete Muhm used to run a bike muffler on his Cabrio in the 80's. Knowing Pete, it did f all.
I was gunna do it but i went the cannon way, i think joel used to run one like a motor bike one on his black bug.
What happened to the space ship
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If you go the after market route, most motorbike mufflers come with a baffle that is easily removable. Though most after market ones cost between 500
and 1200 new....
If anybody in brisbane wants, I have a std muffler from a SV650 they can have to play with. Its got some gravel rash, but hidden under a car it would
be fine. It comes from a 650 V twin, that spins to 12000 rpm (for your calcs above). it does have the standard baffle inside, so makes thisng pretty
quiet and I think would restrict flow.
Cheers
Drew
My post above may have read like a convincing argument.
....but... I now think that one muffler will work a treat.
The reason being, that the bike has peak a torque figure that I think is very near what I get from the car. This means that the bike has near 100%
better volumetric efficiency. So each pulse from the VW engine will have half the volume.
I'll post the results when available if anyone is interested.
The donor bike looks like this by the way:
Got one fitted, it runs good but still sounds like a WWII fighter plane. See the pix below and listen to it here:
on Youtube
Sounds all right... good that you gave it a try !!!
Don't suppose you've gotten a noise reading off of it ??? (free revving at a stable 5000rpm measured at 5m is a common one to come across at
circuits)
Also keen to hear the details, specs, costs etc. if you don't mind sharing...
No noise reading, haven't even tried over 4250rpm. (electronic rev limit).
Details:
Right side OEM muffler for 1997 Ducati 916 SPS $75
SS bend, flange and fitting $100
Anyhow Shaun, what WOULD hurt the most - a red laser, or a green one
I suppose getting run over by a Ford Laser would be even worse, red or green.
A bit hard to tell from the video but it sounds quite nice to me. Better clearance than fatboy setups etc as well. Something else to play with is the length of the entire system, I found that made a big difference to the note on my old 1835.