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What the heck is this?

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Well, you can adjust the power output of a 4 stroke motor based on the size of the muffler exit port.

My 520SX's White Brothers R4 muffler has changable end caps, to adjust power output (granted, I'm sure it's not much!)

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Actually, that thing is touted as an anti-reversion cone, which should be a cone right next exhaust port in the header. If I remember correctly, anti-reversion headers were being advertised years ago in hot rod magazines (with a lot of inflated BS claims).

The cone would be immediately after the exhaust port, and when a reverse shock wave bounced back down the pipe, the edges of the cone would stop it's progess before it caused reversion of burnt exhaust gases into the combustion chamber. This "anti-reversion" was supposedly most effective at lower rpm's.

Maybe someone else could elaborate on whether this really is (or was)effective.... :applause:

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What the hell for only $29 one of us poor saps should be the guinea pig and get one. I'll be number five on that list.

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yep it goes in the header pipe were it fits into the head ,i made one in 02 for my yzf250 it does work sharpens up the bottom and mid but no change on top . it works well if u run a enduro pipe as u need all the help u can get with one on. there is a similar part that goes in the back of the carb to increase air speed .we had it on the dyno on 06crf250 2.5hp increase up to ten grand for about £50 uk money , cheap hp :applause:

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was using stock header with dep enduro tail pipe the dep enduro header is smaller

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I think it's a full choke, great for goose hunting!

I heard that 80 yard shots are the norm with this thing :applause::bonk::cry:

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Explanation #1

REVERSION is the secondary pressure wave that travels back up the primary pipes and enters into the cylinder on valve overlap. As this pressure wave travels back up the pipe, it brings with it all the residual gases still left in the pipe. This is what contaminates the fresh intake charge. Enter in stepped headers and ANTI-REVERSION chambers, placed at strategic locations in the primary pipes. These methods are employed to tune the arrival of the exhaust wave and to diminish the effects of the high pressure in the pipes. The results are higher volumetric efficiency and more power.

Explanation #2

Reversion is simply the exhaust gases momentarily flowing backwards during the overlap phase of the camshaft at low cycling rates. During the overlap phase the engine is on the exhaust stroke and the piston is pushing out the last of the exhaust gases. Prior to reaching top dead center the intake valve begins to open. At low cycling rates the intake charge and the exiting exhaust pulse have yet created any momentum. Thus the piston pushes some spent exhaust gas into the intake manifold. This is why engines with big camshafts idle and sound radical. The exhaust pulses shoot up into intake manifold causing a major disturbance. The cylinders receive an uneven mixture of air, fuel and spent exhaust gas. The piston then reaches top dead center and begins the intake stroke. At this point both valves are open, in fact the exhaust valve in some cases may not shut for another 50 degrees of crank rotation. During this 50 degrees of crank rotation the piston literally draws from both the intake and exhaust valves causing the exhaust gases will momentarily reverse. At high cycling rates the inertia of the incoming intake charge and the out going exhaust pulse keep the gases flowing in the proper direction. Not a problem until you add water into the exhaust stream. Concerning headers, reversion can be severe enough to add water to oil (milky oil), rust valve seats, even stall the engine. This effect only happens at idle, but engines encounter their greatest reversion pulse at shut down.

Patent #1

An improved fluid flow system for enhancing fluid flow through an opening. The first embodiment uses a first extension member for extending an opening through a perpendicular surface and a second extension member with a generally converging introductory section secured in a sealed overlapping relationship to the distal end of the first extension member. A second embodiment uses a pair of conduits of equal cross-section with a bulbous section therebetween with one of the conduits inserted into the bulbous section. A third embodiment with unequal cross-sections with the smaller diameter conduit inserted into the larger diameter conduit and sealed thereto for forming a continuous conduit.

Link to pic (although bulbous chambers wouldn’t be possible with the add-on cone set-up)

http://www.hytechexhaust.com/images/whowe/reversion01.jpg

Test of cones referred to in this post -

http://www.badweatherbikers.com/buell/messages/3842/16474.html

Seems they didn't work......

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Actually, that thing is touted as an anti-reversion cone, which should be a cone right next exhaust port in the header. If I remember correctly, anti-reversion headers were being advertised years ago in hot rod magazines (with a lot of inflated BS claims).

The cone would be immediately after the exhaust port, and when a reverse shock wave bounced back down the pipe, the edges of the cone would stop it's progess before it caused reversion of burnt exhaust gases into the combustion chamber. This "anti-reversion" was supposedly most effective at lower rpm's.

Maybe someone else could elaborate on whether this really is (or was)effective.... :applause:

they are effective , but they are a compromise like most anything you do to the exhaust system , if it was made to open up as the RPMS increased he would really have something

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