Loud cans to replace my crumbling Danmotos?

[agentpineapple]

I never did figure out who made those cans dave, they look well made tho, my two brothers system was tested at brands, its 104db at standstill/5k revs......a touch loud....

[sirch345]

The cans I had before gave a nice boom but were a bit harsh sounding, no idea what they are they came on her from marty, but they look like scorpions

Scorpions are normally marked on the end, inscribed into the metal with the makers name, plus they don't usually sound harsh as the packing doesn't need replacing,

Chris.

[Ckennedy]

Yeah iv got a pair of scorpions for sale, can sell with baffles. Left hand one has a slight dent but very hard to see when fitted as it is underneath and round where the strap goes. Let me know if your interested

[thumperslaw]

just junk the two cans and set up this bad boy..

http://www.dragrace.fi/product_info.php ... pbp8esth02

[VTRDark]

Carl, after shortening the cans it's really smoothed out the low pickup to about 4500 and feel s stronger above, maybe it's just me !

Shify no.... it's Physics my dear Watson, physics Exhaust theory links in the following. All very interesting reading especially the rc51.org link
http://www.vtr1000.org/phpBB3/viewtopic ... 15#p334553

The exhaust system is a tuned length and shortening or lengthening this affects the exhaust pulse waves and scavenging effect. There's pipe diameter as well as this affects velocity but we'll forget about that for now. The pulse wave is the result of the engine breathing, positive and negative pressures sucking in and blowing out, Induction and Exhaust. If you read up on the Four Stroke Cycle you will see there is a point in the timing where both valves overlap each other where there's some power to be had, the valve overlap period. This is where exhaust scavenging takes place if the exhaust pulse hits it at the right time. This is more critical for low down torque and smooth idle. Exhaust scavenging is less critical at top end as things move so much more faster and are near enough at a constant. Generally speaking shortening the system gives gains up top where the scavenging effect is not so critical and lengthening the system gives more gains down low where the scavenging effect is more critical.

(:-})

[Bananaman]

thought it was me!

[playerone]

I've got the slash cut delkevic carbon stubbies and they're fairly loud, cant ride without ear plugs

[toecutter]

I have had a look on Youtube, but as everything is recorded with different equipment its hard to compare.

Not sure on cut down/stubby cans in case I do lose a lot of low end.

Did consider a length of straight pipe from my link pipes but would probably run badly and sound like a tractor

[VTRDark]

Did consider a length of straight pipe from my link pipes but would probably run badly and sound like a tractor

You could do but it would be as long as a scaffold pole, especially as it will higher flow velocity, to equal anything near standard.

Don't dismiss shorties completely if that's what you want but be aware that there are affects on performance and not only will they need jetting to suit but there is an effect on scavenging that one may want to counter act with timing. Cam upgrade anyone

It's like the resticrtor in the right hand side header
http://www.vtr1000.org/phpBB3/viewtopic ... ust+theory
some take this out which is fine for a bit more top end, but will have an effect down low. I'm not entirely sure but believe it's in place to create a secondary pulse wave which helps with idle and low speed scavenging. The same as a balance pipe do on aftermarket headers.

You would be surprised by the effects a different exhaust and scavenging effects can have on a bike, especially a big v twin with lower compression. Move away from an aftermarket exhaust/can that is specifically designed for the bike, then be prepared for not a straight forward plug and play.

You can't have the best top end and best low end. It don't work like that and everything is a compromise. You can sacrifice a little bit off of both the top and bottom and come up with a happy medium if you like. It's all about moving max peak power up or down the rev range according to where you want it. Notice drag bikes/cars, something going for a speed record. It's engine will be very rough and lumpy at idle, possibly barely running and with the idle speed turned right up to compensate. This is because they are tuned for max performance at top end.

(:-})

[Pete.L]

I'm surprised Honda haven't come out with their own version of an EXUP valve. You could have the best of both worlds then, especially on a big twin.
Aren't Yammy also doing a variable inlet valve as well. Surely that's got to be the way to go for the most flexibility and fuel economy.

Pete.l

[VTRDark]

Yep there's EXUP or other variable exhaust tuning. Then there's VTEC for the cams, all sorts of tech. The next stage will be abandoning camshafts altogether and having electronic plunger devices to control the opening and closing of valves. In fact I think they are being used already. IIRC Ferrari have some kind of device like that in a road car. I wonder what they use in F1 cars or on GP bikes. Oh and lets not forget the Ducati desmodromic valve system. All kinds of advancement....or is it. It may mean more parts to fail, and a lot more electronics that we can't work with and also takes character away.

(:-})

[Saintsman27]

Hey guys ... just remember your Honda Firestorm VTR has 2 cylinders
with a cc of 1000 cc ... and well it is going to make noise .. Yes ..
so go for it get the best you can afford or find .... they are truly
demonic machines that when wound up on song are top bollox..
we hear whining high revving 4 cylnders but a V twin is something to
behold..

[Furrybiker]

I have these in stainless steel, those who have met me can tell you that they are not quiet....



From SP Engineering http://www.spengineering.co.uk/index-sh ... =&PageNo=1

However people hate riding with me for any length of time with the baffles out

[grumpyfrog]

Stuart, "Dornoch" fit yeh dain sa far north min?
did you have the bike up with you? some cracking roads up there.

[VTRDark]

those who have met me can tell you that they are not quiet....

That they are not. I must admit they sound lovely, a nice deep tone which I think is more to do with size of the outlet than length. Something else to be taken into consideration when thinking about tone!!



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