Gutted CAT temperature difference...

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Jan 13, 2014 | 12:42 PM

#21

Uncle Paul

Outstanding HDF Member

Joined: Feb 2012

Posts: 2,053

Likes: 39

From: San Diego

Used a finely calibrated temperature device (girlfriends right shin). On 2012 street glide, riding typical back roads, it would turn bright red, and cause annoying sounds to be vocalized.

After de-catting the annoying sounds went away, and the skin on that lovely right shin remained a lovely, healthy skin tone.

Went from a bike that she hated to ride, to one she jumps on with enthusiasm.

For the rider, the heat went from being exceptionally hot, to normally hot.

Good mod.

Bonus point. Once your cat is removed, then you are free to address the hot running lean engine. Using Vied or tuner technology, additional fuel may be added, resulting in a cooler running bike to go with your cooler running pipes.

Summary. If you are riding on a bike with a cat, and you are happy with it, you need to do nothing, however if you have a desire to reduce the heat, this is a relatively easy, and inexpensive option.

Jan 13, 2014 | 01:59 PM

#22

budsbike

Advanced

Joined: Apr 2011

Posts: 58

Likes: 0

From: Greenfield, MN

Quote:

Originally Posted by dribble
Along with platinum, rhodium and palladium the converter uses aluminum oxide,
silicon dioxide and titanium oxide as a wash coat. These materials will start
to melt at 1600 degrees causing the converter to plug up and raise temps enough
to melt the substrate.

When I look up melt temps for Aluminum oxide (3,762F), Titanium Dioxide (3,349F) and Silicon Dioxide (2,912F) I find vastly higher melting temps? I also found some automotive sites that mention the critical temp for a cat to be 2,000F or higher. That being said I will concede that 1200F is on the higher end of the cats operating temperature but still within reason and possible. If you stay on the throttle your pipe temp will get real close to the cat temp. I think the most important message here is if you still have a cat on your bike and have put a tune in it or Xied's on it you're adding more fuel and that is causing the cat operate at a higher temperature. Which I think we all can agree is not desirable!

Jan 13, 2014 | 04:19 PM

#23

dlpuette

Cruiser

Joined: Apr 2012

Posts: 217

Likes: 39

From: Cleveland

Quote:

Originally Posted by Uncle Paul

Used a finely calibrated temperature device (girlfriends right shin). On 2012 street glide, riding typical back roads, it would turn bright red, and cause annoying sounds to be vocalized.

I used that exact same instrument (different model though) and got those exact same results!! When I went from a 98 RK to an 11 Limited, the instrument emitted howling sounds that made my ride most unpleasant. After cat gutting, the temp device calmed down and has been in a more desirable state with no such noises any more.

I wouldn't call this a good mod. I would call it necessary.

Jan 13, 2014 | 04:41 PM

#24

ddm502001

Road Warrior

Joined: Dec 2008

Posts: 1,616

Likes: 17

From: Mid West

My different model is older, has to be analog, would pick at me incessantly with a tapping on the helmet plus the audible alarm would raise in frequency every few miles past ability to handle the heat to indicate time to get off the heat source. Water cooling to the seat area resulted in swampazz conditions unbearable for the rider.

Jan 13, 2014 | 05:53 PM

#25

dribble

Grand HDF Member

Joined: Nov 2012

Posts: 3,751

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From: Here and now

Quote:

Originally Posted by budsbike

I'll restate. These materials will start to sinter at 1700 degrees thus fusing the molecules together which could cause an obstruction in the exhaust flow that would raise the temperatures to the melting point. I originally only challenged Utah Harley's assertion that they do modifications that would lower exhaust pipe temperatures by 600 degrees. The 1200 degree measurement that I referred to was assumed to be the outer shell temp, not the exhaust gas temp, which I will also agree can be about 1200 degrees. Adding a cat-less head-pipe and good fuel and ignition mapping should lower exhaust pipe temps by about 200 degrees (give or take). And let's not even address what they said the cat does as far as emission reduction because they kinda missed the boat there too.

I stand by my opinion that they are full of it.

Last edited by dribble; Jan 13, 2014 at 06:15 PM.

Jan 13, 2014 | 07:13 PM

#26

Uncle Paul

Outstanding HDF Member

Joined: Feb 2012

Posts: 2,053

Likes: 39

From: San Diego

Nobody cares about the exhaust air temp. It is the radiated heat from the pipes that causes all the discomfort.

Jan 14, 2014 | 10:02 AM

#27

krwould

Club Member

Joined: Jul 2008

Posts: 112,202

Likes: 1,316

From: On a hill among the hills, PA

Quote:

Originally Posted by Uncle Paul

Nobody cares about the exhaust air temp. It is the radiated heat from the pipes that causes all the discomfort.

As long as your not playin with A/F ratios... ding ding ding.... a trueism about the whole heat problem.

Air in and air out... the more efficient that happens the happier your motor will be. Cats suck... restrict exhaust and why the heck do we need them on a two cylinder motor?? Stupid friggin EPA!!!

Jan 14, 2014 | 10:27 AM

#28

krwould

Club Member

Joined: Jul 2008

Posts: 112,202

Likes: 1,316

From: On a hill among the hills, PA

Here ya go ucarab.... http://tuneyourharley.com/biketech/c...p-070809-bikes this is with the cat still installed using WB o2 sensors if I read this correctly.... Has to be much less with the cat gutted.... as someone stated earlier like 200* difference.