What!!! MKODAMA. do know what the CAT is for? I was designed for high temp. Its a ceramic block. It burns the unburned hydrocarbons to lower emissions. Higher octane fuel, wrapped headers and a hot cat will drastically lower hydrocarbon emissions. I wrapped my headers to take the heat out of the engine bay and put it down the exhaust to the cat to lower engine bay temp. Cooler engine bay temp means colder, more dense air for the engine. The Internal Combustion Engine was designed to burn oxygen. Fuel was just the catalyst to push the pistons. Fuel octane is very important. 87 89 93. 87 is for a lot of city driving and low compression engines. 89 is for mid-performance city, freeway driving. 93 is for high performance engines with high compression and good freeway driving. Look at Europe, In England (UK) they have one specific octane 95. The rest of Europe usually follows suit. So my point is this. High heat, high octane, AND A HOT CATALYTIC CONVERTER, does increase performance. The internal combustion engine is at its best at high RPM and High Temp. OK. You need to look at a cross section of a CAT. Maybe then you will understand things better.
Yes, the catalytic converter was designed for high temperatures, you are correct on that one. But don't think that it is impervious to heat. Excessively high temperatures will partially melt and destroy the ceramic element inside. Common causes for failed catalytic converters are overheating them or from clogging with excess fuel.
Gas octane is also measured different in the US compared to the EU. The US uses AKI or Anti-Knock Index, which is the average of the RON (Research Octane Number) and MON(Motor Octane Rating) ratings. Europe just uses the RON rating, and is why their fuel octane cannot be directly compared to ours.
For example:
The MON rating is usually 8 to 10 points lower than RON. If you say the european gas pump said 95 RON, it could also be said to be 85 MON. To get the AKI, like what is used in the US,
AKI = (RON + MON) / 2
AKI = (95 + 85) / 2
AKI = 90
So that would mean that 95 octane gas you saw is the equivalent to the "Premium" grade gas you see in the US.
And here's a fun fact: wrapping your headers and cat will create hotter exhaust temperatures and hotter exhaust temperatures or more prone to creating nitrogen oxides, a major pollutant that is measured during emission inspections.
