no cat with stock mufflers
Road Warrior
Joined: Oct 2013
Posts: 1,399
Likes: 1,040
From: Seabrook, NH
I will point an infrared thermometer on the CAT behind the heat shield and on my header in the same spot without a CAT and give you the readings. I am willing to bet there is a huge difference in temperature. Hopefully I will post the numbers this weekend once I borrow my friends IR gun.
Grand HDF Member
Joined: Nov 2012
Posts: 3,751
Likes: 459
From: Here and now
I will point an infrared thermometer on the CAT behind the heat shield and on my header in the same spot without a CAT and give you the readings. I am willing to bet there is a huge difference in temperature. Hopefully I will post the numbers this weekend once I borrow my friends IR gun.
Road Warrior
Joined: Oct 2013
Posts: 1,399
Likes: 1,040
From: Seabrook, NH
Thanks for saving me the troubles and that folks is why my wife's foot is no longer burning when she wear sandals.
Seasoned HDF Member
Joined: Sep 2008
Posts: 20,880
Likes: 33,837
Removed cat from my 2010 Ultra one year after buying it and the heat went away. Anyone that tells you different does not know what they are talking about. The bike became a pleasure to ride even around town in stop and go traffic in the summer. Don't think twice about it, remove it!
Ultimate HDF Member
Joined: Jun 2007
Posts: 9,193
Likes: 494
From: Richmond, VA
I wish I knew enough to join in this fight, but I refuse to be another person spouting opinion as fact. My intent when I purchased the bike was to ditch the cat. Thus far I have not done so. Lots of stories about power gains and heat loss and until some one can post up either dyno tests or thermo charts showing definitive proof of gains/loss, the cat is staying. I will say this, since I took a three inch hole saw and removed the baffles from the factory muffs, the bike actualy sound fantastic, even with the cat still in place. So until I have facts more than.... "this is the truth" or "that is the best", I will continue to enjoy what I have.
Tourer
Joined: May 2012
Posts: 263
Likes: 30
From: Canada, Thailand
I wish I knew enough to join in this fight, but I refuse to be another person spouting opinion as fact. My intent when I purchased the bike was to ditch the cat. Thus far I have not done so. Lots of stories about power gains and heat loss and until some one can post up either dyno tests or thermo charts showing definitive proof of gains/loss, the cat is staying. I will say this, since I took a three inch hole saw and removed the baffles from the factory muffs, the bike actualy sound fantastic, even with the cat still in place. So until I have facts more than.... "this is the truth" or "that is the best", I will continue to enjoy what I have.
Road Warrior
Joined: Sep 2013
Posts: 1,920
Likes: 77
From: dallas
I've done that. 445 with cat. 265 without.
While riding at speed those temps would be mostly equal.
Main heat is from the exhaust pipe exiting the head.
That's what you feel when riding, not the cat.
Road Warrior
Joined: Feb 2008
Posts: 1,275
Likes: 3
From: Arizona
Decatted stock header
Here is another fact to consider. I have a decatted stock header with Klock SS mufflers and rode 127 miles today. I got just over 47 miles per gallon BUT with stock mufflers and a decat I never got over 42 MPG. The Klock mufflers are straight through so less back pressure. Something is working right here.
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Joe Kucinski
Ultimate HDF Member
Joined: Jun 2010
Posts: 5,105
Likes: 16
From: Blaine, WA
I assume that was using a tuner and free flowing exhuast of some sort? I was going to put the cat equipped header back on now that I installed a new map and stage 1 intake - just to see if by some chance that would cool it to a tolerable level even though I suspect I know what the result will be. Maybe I won't waste the time.
Grand HDF Member
Joined: Nov 2012
Posts: 3,751
Likes: 459
From: Here and now
Prior to that I shot the cat several times upon returning home from rides anywhere from 10 to 100 miles. The temp was always in the 425 to 465 range before and always in the 255 to 275 range after.
You are right, you don't so much feel the cat when moving over about 20 mph, but my wife did. When sitting at stoplights, railroad crossings or idling around parking lots, it cooked her right foot and the back of my leg. It doesn't happen anymore.
I'm not one who thinks that you need to remove or modify emission components just to do it. I wanted to leave the cat on and if it wasn't for the heat, I would have. I believe that I had a slight decrease in performance when I removed it but nothing that I can quantify with numbers or dyno results.
My theory is this. Harley could have left the cats in the mufflers and met all their EPA requirements but they would have knocked themselves out of the SE performance market because they would have had to sell SE mufflers with cats, so they moved it up to the head-pipe better compete with the muffler aftermarket.
Last edited by dribble; Jun 20, 2014 at 04:53 PM.