As an automotive expert with years of experience in the field, I can say that using 100 octane fuel is a topic that requires a nuanced understanding. Let's delve into the considerations and implications of using such a high-octane fuel.

First and foremost, octane rating is a measure of a fuel's resistance to knocking or pinging during combustion.
Knocking is the uncontrolled detonation of the air/fuel mixture in the engine's cylinders, which can cause damage over time.
Higher octane fuels are designed to prevent this by allowing for a higher compression ratio without knocking.

For stock engines, which are not modified for high-performance, using 100 octane fuel is generally safe but may not provide any significant benefits. The cooler burning nature of 100 octane can be advantageous in high-performance engines that are designed to handle the increased octane. However, in a stock engine, the cooler burn might not translate into improved performance or fuel efficiency.

One potential issue with using 100 octane in a stock engine is the risk of clogging the catalytic converter. The cooler burn can lead to incomplete combustion, which in turn can cause carbon buildup in the catalytic converter. Over time, this can reduce the converter's efficiency and potentially lead to costly repairs.

Moreover, 100 octane fuel is typically marketed and sold for vehicles that are specifically tuned for it. This includes race cars and off-road vehicles that have been modified to take advantage of the higher octane rating. For these vehicles, the use of 100 octane can lead to better power output and performance.

However, for the average driver with a non-tuned vehicle, the benefits of using 100 octane are minimal. You are unlikely to see an increase in power or a significant improvement in fuel mileage. In fact, using a fuel with a higher octane rating than what your vehicle's engine is designed for can sometimes lead to less efficient combustion and even decreased performance.

It's also worth noting that fuel quality can vary by region and even by station. While 100 octane fuel is designed to be of high quality, it's always a good idea to ensure that you're using fuel from a reputable source to avoid any potential issues.

In conclusion, while it is generally safe to use 100 octane fuel in a stock engine, it's important to consider whether your vehicle is designed to take advantage of the higher octane rating. For most drivers, sticking to the manufacturer's recommended octane rating will provide the best balance of performance, efficiency, and safety.

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expanding on my answer: It's safe...ish to use on stock engines. The fuel burns cooler and may clog your catalytic converter. You certainly won't see any better power or mileage from it, unless you're tuned for 100 octane. It's sold solely for cars that are tuned for 100 octane: race cars and offroaders.read more >>