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the Bish
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As part of my make over, I'll be running drag pipes. I've been reading that short pipes rob low end performance due to reversion. The solution is torque cones or anti-reversion valves. In talking to an indy, the torque cones are just so much snake oil and Il'd be better off using baffles. What think ye?

Thanks​
 

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p38buff said:
As part of my make over, I'll be running drag pipes. I've been reading that short pipes rob low end performance due to reversion. The solution is torque cones or anti-reversion valves. In talking to an indy, the torque cones are just so much snake oil and Il'd be better off using baffles. What think ye?

Thanks​
I think that he may be partially right.

Good torque cones look like they have part of screw driver welded in them. Now I am not going to be able to tell you where I read this because it was about 12 years ago.

There was a write up about straight and the low end power loss. The tech were scratching there heads when one recalled placing a screw driver across the end of the pipe change the power band by giving more torque. So they strapped the bike to the dyno, did several runs with just plain straight. Then let it cool all the way down. Placed a screwdriver over each pipe and did several more runs.

Sure enough the screw driver changed the power band. I think Samson might still have something like this somewhere on their website? If not email them and post the reply.

Now how does a thin rod make the change? It briefly impedes the exiting gases enough to cause back pressure. I have heard of some folks even placing the inserts in different spots in the pipe to experiment with how much back pressure is built up.

I have not read much about the anti reversion valve. I would think that any moving part in an exhaust is subject to way too much heat and will fail over time, but I could be wrong on that.
 

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semi-retired
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no torque cones

p38buff said:
As part of my make over, I'll be running drag pipes. I've been reading that short pipes rob low end performance due to reversion. The solution is torque cones or anti-reversion valves. In talking to an indy, the torque cones are just so much snake oil and Il'd be better off using baffles. What think ye?

Thanks​
khromewerks drag pipe baffles come in 3 or 4 different diameters.
 
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