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Exhaust Query

Posted: Tue May 08, 2007 3:10 pm
by MonkeyBusiness
I saw a race-bike at the track the other day with one of these exhausts.

Image

Now, as I can't imagine that it has much of a baffle, if at all, I was wondering what the pro's and con's of having an exhaust like this would be i.e. no end-can / no baffles?

Would it make a difference to performance, engine compression etc etc.

I really like the idea of not have a big end-can which messes with the sleek lines of the bike.

Posted: Tue May 08, 2007 3:40 pm
by deviant
my belief (and I'm sure one of the racers can give a better answer) is that open pipes give a better top end at the expense of midrange - a bit of back pressure in the system helps with the midrange (I have no idea why), but ultimately, the more free flowing it is, the more top end power it can produce. Hence a lot of modern bikes try to compromise by having valves in the exhaust which restrict the flow at low rpm but open up at high rpm.

I'd expect you'd need to change the fuelling to suit.

oh, and it will be offensively loud!

Posted: Tue May 08, 2007 3:44 pm
by masterofinsanity
doesn't it give you faster pull off speeds too??

Posted: Tue May 08, 2007 3:50 pm
by deviant
what do you mean?

Posted: Tue May 08, 2007 3:55 pm
by masterofinsanity
heads gone blank, you know what i mean you twist the throttle and away you go..

Posted: Tue May 08, 2007 3:56 pm
by deviant
the sort of thing that might be the result of better low/mid range torque?

Posted: Tue May 08, 2007 4:01 pm
by masterofinsanity
yeah summat like that, thats why drag racers use vance and hines pipes aint it? so they get away quicker? now if only bonnie & clyde had thought of using one?

Posted: Tue May 08, 2007 5:47 pm
by Bozzie
masterofinsanity wrote:doesn't it give you faster pull off speeds too??
i just use porn instead ;)

Posted: Tue May 08, 2007 5:55 pm
by RedexRobB
Bozzie wrote:
masterofinsanity wrote:doesn't it give you faster pull off speeds too??
i just use porn instead ;)
Dirty boy! Havent you got girlfriend?

Posted: Wed May 09, 2007 6:52 am
by diesel
if he hasnt he can have mine. everyone else has :smt001

Posted: Wed May 09, 2007 6:53 am
by MonkeyBusiness
Well that was constructive. :smt002

Anyone else have a more solid understanding of this subject, excluding the Porn-Kings? :smt003