Cat or no cat?
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Stellar HDF Member
Joined: May 2012
Posts: 3,156
Likes: 56
From: Milwaukee
Cat or no cat?
I'm looking to start working on a stage 1 upgrade. I already got V&H slipons. Is there a cat in the head pipe. If not, is the exhaust part of the upgrade done? Can I move onto a/c? Do I need a tune or download? I'm not looking to make a beast out of this bike, just want it to sound great and run even better. Any info or suggestions would be helpful.
If it's a new bike the cat is located where the head pipes come together. Some have reported a change in sound with its removal but it does create a lot of extra heat on the right side of the bike. You don't need to tune with the addition of your slip-ons but will when/if you do the a/c. I did slip-ons, still have the stock cat and am waiting on the a/c upgrade (not completely decided on the best path for me.) Bike runs and pulls great, may just leave it stock! 
Road Master
Joined: Feb 2010
Posts: 880
Likes: 0
From: Houston, Texas
Cat removal is a must! It puts off way to much heat and is restrictive. It's an easy fix to get it removed or to do it yourself. I have the stock header with the cat removed and the sound improvement and heat reduction are very noticeable. Some people report performance gains, I noticed a little bit just by the seat of the pants feel, but the main benefit is the heat reduction.
Cruiser
Joined: Feb 2012
Posts: 182
Likes: 6
From: New York
I'm looking to start working on a stage 1 upgrade. I already got V&H slipons. Is there a cat in the head pipe. If not, is the exhaust part of the upgrade done? Can I move onto a/c? Do I need a tune or download? I'm not looking to make a beast out of this bike, just want it to sound great and run even better. Any info or suggestions would be helpful.
Elite HDF Member
Joined: Jun 2011
Posts: 3,832
Likes: 127
From: Coastal Carolina
There has been alot of discussion on the forum about gutting the cat. Some say that it is a must and really helps the bike. Others say that there is no need to remove it, that it's not restrictive at all and that removing it can screw up the way the bike runs because of crosstalk between the O2 sensors.
This thread has an exhaustive (and exhausting) discussion of the subject. All of the varioius opinions are reflected there. Take the time and read this whole thread and make up your own mind. https://www.hdforums.com/forum/touri...eal-facts.html.
For what it's worth, after considering the various positions carefully (and the qualifications of those advocating each position), I personally concluded that removing the cat is unnecessary, not helpful (except for some heat reduction, and the motor is hot anyway), and potentially damaging to the way the motor runs. Those that take the contrary view seem mostly to be of the "I did it and my bike runs fine" variety and without airflow analysis saying "it must be restrictive, just look at it after I cut it in half!" There does not seem to be any engineering reasoning to justify removing it again, other than heat.
But you draw your own conclusions.
This thread has an exhaustive (and exhausting) discussion of the subject. All of the varioius opinions are reflected there. Take the time and read this whole thread and make up your own mind. https://www.hdforums.com/forum/touri...eal-facts.html.
For what it's worth, after considering the various positions carefully (and the qualifications of those advocating each position), I personally concluded that removing the cat is unnecessary, not helpful (except for some heat reduction, and the motor is hot anyway), and potentially damaging to the way the motor runs. Those that take the contrary view seem mostly to be of the "I did it and my bike runs fine" variety and without airflow analysis saying "it must be restrictive, just look at it after I cut it in half!" There does not seem to be any engineering reasoning to justify removing it again, other than heat.
But you draw your own conclusions.
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Cruiser
Joined: Feb 2012
Posts: 182
Likes: 6
From: New York
Thanks for that!
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Road Captain
Joined: Feb 2012
Posts: 507
Likes: 5
From: Florida
For the longest I contemplated removing the cats off my 2012 FLHR but in the end decided instead to go with true duals (no cats of course). I'm much happier with my system set-up. Definitely improved performance and not just seat of the pants. My bike gained torque and top end power. After more research, I also went with PC V and Arlen Ness Big Sucker. I will not detail all but suffice to say I waited until I had all three Stage 1 pieces before installing them on my bike. I had the Sceamin' Eagle Street Performance slip-on's day one after taking delivery and kept those on my bike.