This is a known problem.
You can thank the EPA for this situation. Some/many incorrectly think this is a fuel problem, this is NOT a fuel problem, this is a "lack" of ignition timing problem.
In the world of tuning an engine around the smog laws, you need low ignition timing to keep the oxides of nitrogen (a bad thing for breathing mammals) low. Even though the engine as you can plainly see, isn't happy about this.
I've proven this over and over to people, just raise the timing and the red headers will go away...AND the engine will run better. Unfortunately, currently, we have no way of doing this. The "Exhaust Kit" formally sold by EBR, made this change in the replacement (race only) ECM. Now you/we just have to find one..!
Mike
The fill exhaust race ecm or the tips or either?
Von -
Not sure I understand your question.
The ignition timing maps are found in the ECM.
Mike
The "fill" (full ?)..?
Don't know anything about an EBR "full exhaust" ECM. The only one I know of that EBR sold was the tips that go into the lower muffler along with the required ECM.
Mike
There were two Race ECMs for the RX/SX.
One was calibrated for the exhaust finisher kit (which removed the secondary muffler and installed tips on the primary muffler.
The other was for the HMF muffler. This was not a full system - it maintained the stock headers.
Both ECMs were only available with the respective kits and they were unique calibrations for those configurations.