AFR and catalysts

[DiasDePlaya]

What about the catalysts and AFR? Catalysts are assumed to require an AFR of 14.7, but with fatducs, remapping of the ECU and the like to use a less than 14.7 AFR going to unburned fuel reaching the catalyst. Those who have installed some of these devices on a bike with the original muffler, have noted higher temperatures or other symptoms?

[mollycbr123]

I was a bit concerned about the effect on the cat at first (with fatducs), but I've had them on thru two very hot summers now, and no problems with high temps. I just came in from an hour ride, about 50deg F outside, and the highest temp on the dash was 158F.

[Turkishexpress]

running richer = less heat

[DiasDePlaya]

I'm asking about heat in the catalyst, not the engine.

[Mr Sunshine]

Don't worry about it. You aren't going to make so rich that it'll nuke the cat.

[mollycbr123]

Originally Posted by Mr Sunshine

Don't worry about it. You aren't going to make so rich that it'll nuke the cat.

I didn't think so, but my bike was one of those that had the burnt smell after a ride. It turned out to be the melting plastic cover on the exhaust flapper cable (remember that discussion?). I put the fatducs on very early on, so the thought that the smell might have been from them burning up the cat did cross my mind.

[Turkishexpress]

less heat from the engine = less heat to the pipes = less heat at the catalytic converter


Unless you run leaded fuel your cat is going to be just fine. Rest easy.

[Mr Sunshine]

Originally Posted by mollycbr123

I didn't think so, but my bike was one of those that had the burnt smell after a ride. It turned out to be the melting plastic cover on the exhaust flapper cable (remember that discussion?). I put the fatducs on very early on, so the thought that the smell might have been from them burning up the cat did cross my mind.

Yup I remember. . It'll also smell from the grunge you'll get from the road due to the heat.

[mollycbr123]

Originally Posted by Mr Sunshine

It'll also smell from the grunge you'll get from the road due to the heat.

True. The last few weeks the bike has smelled like burnt leaves when I roll it into the garage. I got a lot of leaves on the driveway to rake up.

[wcieslik]

+1... Smells like a hot Sydney summer if it's a dry day. MMmmm Warm Eucalypt smell !!