Catalytic converters on Katana 1100?

[John Kat]

I'm so happy with my restomod Kat that I'm wondering if I could add some catalytic converters to my exhaust pipes?
The reason beeing that as I ride most of the time with my wife riding her own Triumph Street Triple R, she gets intoxicated by the exhaust fumes...
I know that cat converters must run within a specified AFR range but if they are not too expensive who cares if one has to change them now and then?
Any experience out there?
Who are the main suppliers?
Happy New Year to all of you!

[posplayr]

They only work in a very narrow AFR range produced by EFI.
there maybe some brenefit, but doubt it would last long.

you should consider an EFI upgrade if serious.

[TxGSrider]

If theres that many fumes, you might consider leaning the carbs out some?

[posplayr]

If theres that many fumes, you might consider leaning the carbs out some?

And WBO2.......

[Guest]

heh, the diff between euros and yanks, you guys try to add cats, we delete them!

[Nessism]

Sounds like a fun project. Hopefully you can find some cheap takeoff cats to try. Even if they aren't super efficient it should be an improvement.

[roeme]

Cool idea. My V7 has Cats. I was quite surprised by this, as I always thought of the big chunky units on cars when it came to cats.

AFR is not the primary concern for cats, but rather temperature and O₂ levels of the exhaust gases. AFR is 'just' a means to achieve the correct conditions.

I'd look into an EFI mod as well, no use in hacking up the exhausts just to shift pollution from air to landfill.

[2BRacing]

I'm so happy with my restomod Kat that I'm wondering if I could add some catalytic converters to my exhaust pipes?
The reason beeing that as I ride most of the time with my wife riding her own Triumph Street Triple R, she gets intoxicated by the exhaust fumes...…..

The easiest and simplest solution is to let your wife on her ST3R ride in front of you!

[bwringer]

If the end goal is making life a little more pleasant for your wife, running the exhaust through a catalytic converter would not help much -- it would still be highly unpleasant and possibly even more unpleasant than raw exhaust. Lots of sulfur dioxide, for example (rotten egg smell). And an interesting stew of lots of other half-burned and half-converted hydrocarbons, oxides, acids, etc.

Plus, running rich exhaust from a carbureted engine through a cat makes it really REALLY hot. Like, glowing red hot. If you remember the early days of catalytic converters when carburetors with sticky automatic chokes still roamed the earth, you might be familiar with this. It was actually pretty dangerous at times.

Still, it's a pretty interesting question.

And you have to wonder what might happen if you tried to adapt an existing fuel injection system with O2 sensor, cats, and all the rest (like from a Bandit GSF1250) to an older air-cooled engine.

[Gorminrider]

oh, and what about motorcycle oil? "Car oil" is now specific to cat converters...don't I remember that the "old" oil was rotting out the cat-converters and so they changed it to be death to our sump-oil clutches?...(oboy- an oil thread!)

[posplayr]

It is hard to separate a Catalytic converter from EFI. You can run EFI without a CAT, but not the other way around.

https://www.greggsauto.net/2013/08/murder-catalytic-converter/

http://www.efi101.com/forum/viewtopic.php?p=43679&sid=6844e3f403f3234969381208c190b8d6

roeme

AFR is not the primary concern for cats, but rather temperature and O₂ levels of the exhaust gases. AFR is 'just' a means to achieve the correct conditions.

I'm not sure what the relevance of this statement is. Sure temperature and O2 ranges are commensurate with proper AFR, but most modern CAT systems have a lambda (WB02) sensor at both the inlet and the outlet as part of tight AFR control around the CAT. AFR is the primary control variable plain and simple and while I can't find a reference at the moment, but as I recall there is a very narrow band (for example) 14.7+/- 0.2 that is required to maintain conversion efficiency.

A typical CV carb AFR is lucky to be within 11<AFR<13 and it is jetted rich just to prevent predestination so you are never even close to the 14.7 optimum.

[Nessism]

Cat's hit the market back in 1976, long before EFI was popular. I'm not saying that there are not compromises involved, but saying carb's and Cat's can's coexist is incorrect.

[John Kat]

AFR is the primary control variable plain and simple and while I can't find a reference at the moment, but as I recall there is a very narrow band (for example) 14.7+/- 0.2 that is required to maintain conversion efficiency.
.

As far as I know there are two types of AFR sensors: the narrow band with the kind of tolerance you state and the wideband (more expensive) type that's used with AEM type ECU's and AFR meters.
The car guys state that the cat converters will die if the AFR goes below a 11 to 1 ratio.
Wikipedia has a good article on the subject: https://en.wikipedia.org/wiki/Catalytic_converter

[posplayr]

As far as I know there are two types of AFR sensors: the narrow band with the kind of tolerance you state and the wideband (more expensive) type that's used with AEM type ECU's and AFR meters.
The car guys state that the cat converters will die if the AFR goes below a 11 to 1 ratio.
Wikipedia has a good article on the subject: https://en.wikipedia.org/wiki/Catalytic_converter

narrow band is like a dot matrix printer(old), with today’s electronics most things you buy will be WBO2

[JTGS850GL]

Actually narrow band O2 is like a single dot. In reality it's like only checking for a zero crossing at stoichiometric (14.7) A/F ratio. There's a little resolution near that crossing point but not much. WBO2 is the only way to go if tuning using O2. Much more linear through a wide A/F range. There are a few DIY WBO2 sensors on the market for cheap. Only use one that's preheated as they need a certain amount of heat to work properly.

As for carbs and CATs, they can be used together but the CATs must be located as close to the heads as possible and a air injection system is pretty much a must.

Back to the original poster... If she's running rich enough to stink that bad, you need to consider doing a proper tune. Something's amiss if the exhaust fumes are that bad.