Exhaust swap - non-cat equipped to a cat-eqipped.

[Stealth]

I'm in Australia and I own an '04 which has an 02 sensor and CATs. I have secured a full exhaust system off a pre-cat BB and plan to fit it to mine. Now this raises a few questions and I was wondering if anyone had experience with this...

Q for non-cat equipped bird owners;

They don't have an O2 sensor do they?

Q's for anyone who might know;

Even with out a power commander.... can I just add an 02 eliminator. Ie, they work without the PC?

Any dramas that I need to be aware of in replacing the headders? New exhaust gasket required I assume..

Tanks

[Northman]

Q for non-cat equipped bird owners;

They don't have an O2 sensor do they?

No' date=' as far as North America goes. Only the California bikes had cats, and they were also equipped with O2 sensors.

Q's for anyone who might know;

Even with out a power commander.... can I just add an 02 eliminator. Ie, they work without the PC?

As far as I know, yes. The O2 eliminator is designed to fool the factory ECU into thinking it still has the sensor installed, so no PC is necessary, although beneficial for tuning.

Any dramas that I need to be aware of in replacing the headders? New exhaust gasket required I assume..

Straight forward swap, as long as you stick with the FI exhaust system.

But why change the whole system, anyway? The cats are in the inlet to the cans, so swapping out the cans will remove the catalysts, without the fuss of changing the header. Only difference in the headers is the bung for the oxygen sensor.

Tanks

[Stealth]

Thanks Nothman...

AFAIK, there is also a cat (two actually) in the headers just after they join from 4-2 in the flat square section. Hence the name HECS-3? Two in the cans and one in the header? When the system arrives, I will poke something up there and have a look.

Alos AFAIK, the Australian model is the same as the Cali as far as pollution goes anyway

[Stealth]

Actually I think you are right North... Not sure where I got that from but this is what Honda say;

‘3-Way’ Catalyser. The final components in the CBR1100XX’s low-emissions system are the cylindrical catalyser units installed in the exhaust system immediately before each of the large-capacity canister-type silencers. These compact ‘3-way’ catalytic converter elements complete the system’s high-efficiency operation by chemically minimising the emissions of CO, HC and NOx gases.

[JasonW]

I don't think there are any cats in the header itself. Those flat areas in the collector are just baffles. BUT I can't say I've been inside a California spec header.

Here's that area in a 49 state model, though.

Edited to add correct pic. :oops:

[Stealth]

O'right.....

Now all I need is that same pic from a CAT equipped bird....

[JasonW]

Yeah, your right......that pic is pretty worthless to ya.

Sorry, it's the best I could do.

[Stealth]

No, that's very helpful actually...

When the headers arrive I know what to look for