HarleyTechTalk

I have a 2010 StreetGlide with the 2 into 1 factory pipe and stock muffler. I would like to keep the stock set up but have the cat removed.

I think I saw on here a while back a place that cut the pipe removed the cat and welded it back together. I tried to search it out but could not find it.

Anyone know where I could get this done?
Thanks,
SR

Fullsac

Quote from: autoworker on March 21, 2011, 03:15:55 AM
Fullsac

If I'm not mistaken Fulsac is no longer offering this service. They do offer a replacement X-pipe which replaces your original and uses your stock heat shields.

I saw an article on another board about drilling the cat out using a large diameter masonry coring drill. Looked like a promising method. Here's the link: http://www.cvoharley.com/smf/index.php?topic=27814.0

Good luck!
Frank

Doc of Doc's performance says bad idea and Doc is a smart man.

Does he say why?

Thanks Guy's

Quote from: sandrooney on March 21, 2011, 04:43:18 AM
Does he say why?

Thanks Guy's

tuning issues due to O2 sensor cross talk. 

Thanks Jeff

Quote from: Jeffd on March 21, 2011, 04:56:48 AM

Quote from: sandrooney on March 21, 2011, 04:43:18 AM
Does he say why?

Thanks Guy's

tuning issues due to O2 sensor cross talk.

It's possible if they're threaded into a common collector, but then again, why would HD do that? I understand that the O2 sensors should be isolated to sense respective exhaust streams but can't see how removing the catalyst substrate would influence crosstalk. Maybe have to take a closer look as I have a 2011 with 2-1-2 system.

American Custom will do this for you.  They call it their PowerFlex header.  I'm not being argumentative, just reporting what I read, but if you search the web you will see where many, many people have removed the Cat with great results being reported.

http://www.americancustom.com/products/slip-on-mufflers/the-bomber

This the one I cut open and gutted.  I can tell you that the O2 senors share a common void. 
This is how Doc explained it to me and he is 100X smarter then me when it comes to this so he can explain it better. 

There is one 02 sensor that is in a tube and but the other is not protected because it is in the big void that the cat used to fill. The Cat provides enough back pressure to protect the one sensor in the big area and the cat stops 99% or the reversion (negitive pulse wave) coming back up the pipe. When you remove the cat reversion takes over taht void and the 02 sensors will now cross talk........I know this for a fact Jeff I'm not guessing or blowing smoke. Both 02 sensors have to be in a tube at least 6'' to stop the cross talk.

I asked American Customs if they altered the chamber after they removed the cat and they either would not or could not tell me,but it seems like if they did alter it they would be able to say, so I assume they don't.

I guess it comes down to who are you going to believe, I tend to believe the guys that tune for a liivng when it comes to tuning advice. ie Doc, fltri etc both highly respected and both say a bad idea that is good enough for me as I sold the pipe instead of using it.

Quote from: Jeffd on March 21, 2011, 03:06:52 PM
This the one I cut open and gutted.  I can tell you that the O2 senors share a common void. 
This is how Doc explained it to me and he is 100X smarter then me when it comes to this so he can explain it better. 

There is one 02 sensor that is in a tube and but the other is not protected because it is in the big void that the cat used to fill. The Cat provides enough back pressure to protect the one sensor in the big area and the cat stops 99% or the reversion (negitive pulse wave) coming back up the pipe. When you remove the cat reversion takes over taht void and the 02 sensors will now cross talk........I know this for a fact Jeff I'm not guessing or blowing smoke. Both 02 sensors have to be in a tube at least 6'' to stop the cross talk.

I asked American Customs if they altered the chamber after they removed the cat and they don't.

I'm wondering if they're actually looking at pre-cat VS. post cat oxygen levels to determine reduction efficiency? This is a strategy that has been in automotive applications for years and is actually a catalytic converter diagnostic function.

Good info thanks. SR 

I just called American Custom and they said that there is absolutely no crosstalk or tuning issues with removing the cat.
I did a search on other forums and could not find any negatives on the subject. I would like to richen up the the AFR and have read that can ruin the cat and possibly the engine.

I hope Bob or Doc will chime in and give their input.
SR

Quote from: Superglidesport1 on March 21, 2011, 03:11:44 PM
I'm wondering if they're actually looking at pre-cat VS. post cat oxygen levels to determine reduction efficiency? This is a strategy that has been in automotive applications for years and is actually a catalytic converter diagnostic function.

That's how it's done on autos, but it requires O2's downstream of the catalyst.  I can't see any good way to do it with both sensors pre-cat.

Here is a good read with regards to AFR richness when a cat is in place:

http://tuneyourharley.com/biketech/content/xied-impact-catalytic-converters

Quote from: sandrooney on March 22, 2011, 06:33:56 AM
I just called American Custom and they said that there is absolutely no crosstalk or tuning issues with removing the cat.
I did a search on other forums and could not find any negatives on the subject. I would like to richen up the the AFR and have read that can ruin the cat and possibly the engine.

I hope Bob or Doc will chime in and give their input.
SR

I would expect AC to say that after all they are making money removing the cats. I trust both Doc and Bob know tuning and neither would have any reason to tell me this if it were not true.  If you use an entirely  open loop system for tuning like PCV that does not use O2 sensors you should be fine.

Thanks This is good info.
SR