For the cost, it seems de-catting the head pipe would be cheaper than buying new headers. Would there be any performance gains in buying the vance and Hines power duals vs de-catting? I'm planning on using the vance and Hines monster oval slip ons.

 

I'm sure the answers will be all over the place, but IMO, Yes you will get better performance with the power duals.

Decatting a stock header won't leave you with a properly optimized chamber where the two pipes meet and again separate. Also the O2 sensors are subject to crosstalk with the cat removed on the stock header making it difficult to get your tune perfect.

You will get better back pressure, low end torque and a better tune with the Power Duals or another quality 2-1-2 header like the Fuel Moto.

 

I've heard various theories on the cross talk issue but my understanding is because the sensors are before the cats that any changes made downstream from them would not affect their readings? Also, looking at some of the pictures of people's bike's that have decatted them, it looks like the stock harley header is a 2 into 1 into 2 configuration. Can anyone clarify? And thanks for any insight.

 

Yes 2 - 1 - 2

 

Yes the HD is a 2-1-2 just like the Power Duals you're considering. My point was that the chamber on the HD was designed with the Cat in mind. Removing it, changes the way the gasses swirl, resulting is less efficient flow, less back pressure and the O2 sensor cross talk.

The Power Duals and the Fuel Moto 2-1-2's have chambers and O2 sensor locations designed for no cat. The HD system works very well with the cat in place as designed. Rip the cat out and it's not working as designed. So you get less performance, which was your original question. How much less and if it matters to you, I don't know but it will be less.

 

You can ramble about whatever theories you want but bottom line is tons and tons of guys are running de catted stock headpipes and are very happy with no negative side affects . Is it the best way to go? Probably not but is it cheap and easy ? Yes

 

Not saying a decatted header won't work. The OP's question was would there be a performance advantage in using a properly designed catless header? Yes there would.

 

I wonder if fuel moto has any data from a dyno test showing what one of their header pipes do vs a de catted header. I like their systems, just trying to see if the performance increase justifies the cost. Im kind of a numbers junkie that way....

 

I'd like to see that as well.

 

I don't think we will ever see a test like that to much of a chance of loosing sales if the HD pipe comes close to a aftermarket head pipe just a guess