Cat removal

[rogue17]

I've been playing with the idea of having my catalytic converter removed from my 2013 NC700X. Spoke to the guys at the Honda dealership and they said they could do it for me and have done it before on the NC. In researching the topic, it seems to have positive gains - more volume and better sound from the exhaust and better fuel efficiency, and few draw backs (at least in the short term). Just wandering if anyone has any experience with this? Also, your opinions as to whether or not this would be a good idea would be valued.

 

[misterk]

Where is the cat located?


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[bamamate]

First, you are going to get blasted on here for even thinking about removing the cat as it is the main component for reducing emissions. Second, the cat is most likely the biggest hindrance to performance improvements. Changing the muffler does basically nothing for performance because the cat is the hindrance. There is a cat delete pipe sold in the UK. I haven't seen it for sale in the U.S.

 

[bamamate]

Where is the cat located?


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Follow the exhaust pipe out of the head. The first bulge (canister) you come to is the cat. It is right by the oil filter.

 

[Fuzzy]

Leo Vince sells a cat eliminator pipe if you are set on doing it.

 

[Beemerphile]

Spoke to the guys at the Honda dealership and they said they could do it for me and have done it before on the NC.

The dealer would be subject to fines up to $25,000 if caught doing this. Sounds like a horrible business practice.

 

[Midnight Rider]

The dealer would be subject to fines up to $25,000 if caught doing this. Sounds like a horrible business practice.

Ask VW, among others, they should know...

 

[RinconVTR]

Motorcycle emissions do are not tested (in most States) to the level cars and trucks are. Its why dealers can modify these systems and never pay a price, no one cares.

However, from my experience, only removing CAT's or even including pre-CAT's and the main CAT in from cars have only slight performance gains. Only those doing many other mods that slowly add up the HP in single digits and even fractions, care to take this route.

IMO - dont bother doing this as a single mod. If you're doing 3-4 or 5 other mods for power...then may be. But good luck selling it later!!!

 

[2brnut2b]

If you really want to do it, you should consider buying a Leo Vince decat pipe instead of modifying the original pipe because it is irreversible and illegal to do so...

 

[TigerDude]

Yeah, I'm one of the people who thinks removing the cat is sociopathic behavior. I also doubt you get much out of it on the NC, since the engine is so very engineered to be exactly what it is.

 

[Johninaz]

I am not sure but if the o2 sensor is downstream of the cat but be prepared for the results from confusing the computer. I don't know for sure but should the computer lean the mixture from bad o2 sensor readings very very bad things could result. Lean enough equals overheating and burning pistons and valves.

Additional I agree with TigerDude regarding the social aspects of tampering with the emissions equipment.

 

[670cc]

The OP is in SA (South Africa, South Australia, South America, San Antonio ???). Who knows what the laws are there regarding catalytic converters? Still, it's on the planet Earth where we all live and breathe. Removing the cat would be irresponsible.

 

[TigerDude]

I am not sure but if the o2 sensor is downstream of the cat but be prepared for the results from confusing the computer. I don't know for sure but should the computer lean the mixture from bad o2 sensor readings very very bad things could result. Lean enough equals overheating and burning pistons and valves.

Additional I agree with TigerDude regarding the social aspects of tampering with the emissions equipment.

There is only 1 on the NC, and it is before the cat.

 

[supertux1]

Here's an older post about it:
http://nc700-forum.com/forum/nc700-technical/4985-exhaust-system.html

And a video:
[video=youtube;HADOcrcMikA]https://www.youtube.com/watch?v=HADOcrcMikA[/video]

Everything I know about the NC700 and the converter says that you won't get much of a performance boost out of it.

However, if you are in a country that still uses leaded fuels, it may be advantageous to remove it it since the lead is going to kill it anyway.

 

[rogue17]

I live in South Africa, the laws are clear for cars but not so for motorcycles when it comes to this mod as far as I can tell. I can't imagine the Honda dealership agreeing to do it if it was illegal and fine inducing here.... although, this is South Africa.

However, I agree the mod would give little, and even unnoticeable power gain on the NC, considering its original purposed design. I originally considered the idea mainly for the noise increase from the standard muffler and fuel efficiency , though I doubt those would be hugely substantial either. The problem is that exhaust systems or even decent slip-ons are laughably expensive here because of how weak our currency is at the moment and the fact that they are imported.

I even considered modifying the stock muffler for a bit more noise, but recent horror stories on that topic deterred me from the idea. Also, I'm not hugely fond of chopping my NC into bits and pieces.



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[DirtFlier]

The NC engine is designed for low RPM and excellent fuel economy so removing the CAT will not suddenly convert it into a screaming CBR600RR.

Removing the CAT reminds me of an article in Hot Rod magazine decades ago when the air-cooled VW was so popular in So Cal. They wanted to do an eval of the aftermarket exhaust systems for the VW so gathered a dozen or so examples and found a standard VW in good condition, then lashed it to the dyno. What they found was that with the exception of one system, all the others actually LOST power and the one that gained only showed a tiny improvement.

That fallacy is still alive today with young kids who bolt "turbo mufflers" to their import cars.

 

[rogue17]

Thanks DirtFlier.

Thats quite interesting, and yet somewhat unsurprising. It's great that they actually tested the theory and have hard figures to go by. I can imagine the effect of removing the CAT would be slightly different on each engine, and rather unpredictable from model to model, especially older vs newer ones.

Do you think engines are designed to run on a certain amount of "back pressure"? A pressure partly created by the CAT? I did see a comment in another forum a good while back, but it was never concluded.

If it is so, what would the effect be if running the engine without that pressure?

Haha "turbo muffler".. . that's just great!

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[DirtFlier]

Yes, I think engines in general are designed to run with xx-amount of back pressure for various reasons. And many engines have negative pressure in the air box and will not run properly without the air box being installed.

 

[Beemerphile]

Yes, I think engines in general are designed to run with xx-amount of back pressure for various reasons. And many engines have negative pressure in the air box and will not run properly without the air box being installed.

My new BMW has a servo flapper valve in the exhaust system to create additional back pressure at low rpm's to improve low end power and torque. Of course, it is the first thing some modders remove thinking, I guess, that the factory spent the money to develop it and put it there because they want the engine to run worse. The NC is designed from the first CAD screen as a low RPM torque motor. Mods like this have the very real potential of lessening the power and torque where you can use it and making it "better" at a place where the engine cannot even run.

Just think... With a few weeks of dyno time and a couple of grand in engine mods you could probably get the NC engine to make as much power as a stock Versys.

 

[dduelin]

My new BMW has a servo flapper valve in the exhaust system to create additional back pressure at low rpm's to improve low end power and torque. Of course, it is the first thing some modders remove thinking, I guess, that the factory spent the money to develop it and put it there because they want the engine to run worse. The NC is designed from the first CAD screen as a low RPM torque motor. Mods like this have the very real potential of lessening the power and torque where you can use it and making it "better" at a place where the engine cannot even run.

Just think... With a few weeks of dyno time and a couple of grand in engine mods you could probably get the NC engine to make as much power as a stock Versys.

I thought the late model boxer exhaust flapper valve was in part to help pass noise standards.