BRAVO!!!! :yelclap:The octane rating of gasoline is a rough measurement of how resistant it is to spark knocking. When the spark plug ignites the gas you want a nice even burn across the top of the piston. When the gas doesn't burn evenly it causes shock waves or vibrations if you will. These vibrations can cause engine damage. In hotter weather it spark knocks and even when it is so slight you cannot hear it (marbles in a can) the knock sensor on the side of the engine block detects it and sends a signal to the ECU. The ECU says "man I gotta stop this detonation" so it retards your ignition timing. Retarding the timing in turn decreases your power output of the engine.
If you have ever ran interstate on a 95 degree day with the air on and you hit a hill you can notice a difference between 87 octane and 93 if you know your car well and pay close attention. If you are in a cooler climate you may never notice, but be sure the engine computer is going to protect its engine as best it can.
The little Mitsubishi 3 cylinder engine on the back of your Fortwo is in the worst of conditions. It does not get really good air flow over the outside of the engine anyway. The heat does pool somewhat over the top of the engine in it's little cavity. There is no air flow when you are sitting still because the radiator and cooling fan are in the front. Hot days and engine load can be brutal.
Your little engine is smaller in size than a Harley Davidson motorcycle. It has 10 to 1 compression which is pretty high. Driving in auto mode causes the engine to be in the lower rpm range most of the time so coolant flow is slower at lower RPMS but the engine is pulling at a higher load due to a lower RPM. You are only circulating about a gallon of antifreeze to cool the engine. The Fortwo gets a bad rap for only being 70 horsepower, but that little engine is a workhorse and you can lug it down to 1500 RPM and it will pull as smooth as silk and never misfire.
Heat is your engines worst enemy with low octane fuel and it is hard to find good gas that isn't 10% ethanol made from corn. So while you are motivating down the road at 50 MPH in cool air conditioned comfort on a 85 to 90 degree day remember your little engine out back that is working it's butt of for your comfort. It gets good mileage and it isn't your typical car, but I think mine deserves care and good fuel. If you take care of it, it will take care of you. I say all of this because I ask a lot of my Smart. You might do fine on regular on not so hot temperatures but I'm not willing to find out the error of my ways by destroying my engine. I tore my engine down at 36,000 myself to replace burned valves and it is hard to do. Access is so awkward to get at the engine for anything that's why it is easy to neglect it checking oil, fluids etc,... So trust me I know what engine damage is, how costly replacement parts are and how hard the labor is to put it back together. I have been a car mechanic for over 40 years and have seen a lot. I know how to take care of a car because I fix ones everyday that people don't take care of properly.
I probably push my Smart more than most because I do a lot of towing in these steep West Virginia hills. I can fill Max up from bone dry to full for $23. For 8.5 gallons of gas it's not going to break the bank to fill it up with high test. You get great mileage anyway and even it didn't help, my peace of mind that I'm doing everything I can to protect my car is well worth it to me. When I'm on interstate with that car hauling trailer in the middle of a long hill and Max is pulling his heart out for me keeping me at 60 mph in air conditioned comfort, it's very much worth it. I can only speak for me. DCO
Yea if it is first class then for sure I'm upgrading. However if its advertised as first class however is still Coach then I'm definitely not paying. I just started tracking my fuel usage, so after I get a baseline on premium gas I'm going to switch to regular to see if I get better mileage.And all agree that the smart WILL run on 87. But you get very low MPG,and make engine work harder. As a friend once
said,"it only costs a little more to go first-class"!!.......................
If a vechile does not detonate on 89 octone why would it decrease engine life. That is an ignorant statement. I would suggest that we have better fuel here in the USA vs Europe. I have no proof but we are lots less money and refine it here.