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Question regarding cat removal.

6K views 39 replies 15 participants last post by  fabianomc1 
#1 ·
I just put my 09 R6 in the shop for a custom exhaust installation. We removed the stock exhaust and the bike sounds exactly the same without it cause of that stupid cat. I was told that if I got the cat cut out and a y pipe installed i would need to get a power commander and have it dynoed. My question is this. Would it hurt to run the bike after installation of the new exhaust before getting the power commander or having it dynoed?
 
#4 ·
full exhaust....bazzaz or pcV. done and done.
 
#9 ·
you wont need a power commander at all if you get the mjs header or the 03-05 header mod. if bikes from r6's 03-05 were able to run perfectly fine with no power commander and a slip on then why is it now 5 years later everyone feels that a stock header needs a power commander. Please someone explain the logic to help me understand what I missed (sarcasm)
 
#15 ·
third gen r6's are tuned to run with the cat. if the op gets rid of it, he's messing with this setup. it'll mess with your valves and causes loss of backpressure. it also messes with your fuel/air ratio thus requiring a re-map.
 
#23 ·
Your bike was mapped at the factory to compromise performance to meet emission and sound laws and regulation. Yes the bike will run with a full exhaust, slip on, what have you with out a PCIII. You don't ABSOLUTELY need it, but it will not be up to its full potential.

A 100% stock bike straight off the show room floor will benefit from a fuel management system. Look at the Power Commander maps, there is a map with different values for a stock bike. The bike runs lean from the factory to meet emissions.
 
#25 · (Edited)
"The 3rd gen has the honeycombs and cat built in, so if you ONLY swap out the can, there's not enough change in the system overall to warrant a fuel management system."

3rd gens run lean too from the factory. Not to mention, most slip on systems remove the Exup valve changing the characteristics of back pressure. So there is a significant change.

Any change will alter your air fuel ratio. It comes down to how much do you care about your air fuel ratio being 14.7:1 Running lean, runs hotter, less life. Running rich, fowling out plugs, clogging said catalytic converter, fouling 02 sensors and excessive carbon build up on the engine internals.
 
#28 ·
Because the 03-05 and 06-09s models come stock "mapped" without a cat. The 06-10 R6R models come with a cat and honey comb headers, therefore "mapped" for said restrictions. As soon as one removes the cat and honeycombs, the stock mapping gets completely construed, thus causing the motor to run even more lean than from the factory. I.E, ya need to get some type of A/F management system...:fact

On the 03-05 and 06-09s models....no cat....the stock mapping can be used (with very minimal ill effect) when changing around the exhaust system...
 
#33 ·
The stock ECU doesn't know what to do with the feedback from a wideband O2 sensor. It reqiures a module like...oh I don't know...the Dynojet AutoTune to interface with it, but the AutoTune doesn't interface with the ECU directly. It communicates with a Powercommander. So your back to the remap. This setup just does it automaically.
 
#36 ·
Hahahahaha. The big so called cat under these bikes is the MUFFLER! Like an automotive style, the slip on everybody refers too, is like an exhaust tip. The actual "cat" part is in the the two pipes in between the Muffler and the 4 main header pipes. Trust me, i have dissected my stock exhaust all apart to see what was going on. The cat is a honey comb, and it flows straight though. You can shine a flashlight in it and see right though it. But has a ton of surface area that stays crazy hot to burn any unburnt fuel that comes out of the combustion chamber, for emissions reasons. The big restriction is in the muffler, the big box under the bike. Take some time to cut shit apart and see whats going, so you better understand things. Im currently running an 05 header and Late model GYTR muffler. And yes it acts like a muffler. It has perforated core with packing. The stock slip on is straight though, basically no packing, and only a few perforations for tone, and the EX up valve. Like a valved exhaust tip. LOL! Yamaha has to meet strict epa standards for pollution and noise but still have good performance too. But we all like our bikes loud! Including me! Im sure ill hear all kinds of good comments back on this. HAhahahaha! Have fun with it.
 
#37 ·
i put a full Graves on my 09 and did not spend the money for the pc5 at first (Titanium header turned blue in less then 500 miles) so if u wont to get rid of the cat u will need a pc5 or your bike will run to lean its the best thing i've done to my bike so far
 
#38 ·
Alright. So my bike is done. Muffler was cutout completely, o2 sensor reinstalled, its been rainin all day so i wont be able to pick up the bike until tomorrow. I did however head down to the shop to check it out and was able to snap some shots and get a vid from my phone. Yes, i said phone so audio is not that great but you get the idea. Once I get her home tomorrow I will take better pics and get a better vid. she hasnt been dyno'd yet, but thats comin.





http://www.youtube.com/watch?v=gX_UFBk9tF0

:FU:FU:FU:FU:FU:FU:FU:FU:FU:FU:FU:FU:FU:FU:FU:FU:FU:FU
 
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