Ethanol is stupid, while it has a higher octane rating it will also give you ~20% less fuel economy. Why you ask? Cause ethanol has lower energy per unit than gasoline, so more ethanol is needed to equal the output of gasoline. Yes you can make alot of power from alcohol but at the cost of efficiency, but who cars with a race car? But the government mandates certain amount ethanol in fuel because of lobbyists. kinda funny the government wants more fuel efficient vehicles while making fuel less efficient and cars heavier with safety equipment.

I think people have the wrong idea about octane. Octane simply allows more timing and compression of a motor without pre-ignition, this means 93 or 103 is no more efficient than 87. Timing and compression is what makes power and effiency of a motor. Putting 93 in a motor designed to run 87 is like taking sugar pills when your sick, Placebo

 

you should only run 87 in your stock 4.0 as that is what it runs best on.. Running a higher octane gas consistently can actually do harm and most certainly will never help you

 

How could it hurt? If its actually more octane, I don't see how thats bad. We should send this in to mythbusters.

 

If your running race fuel... thats the only thing I could ever think of that would damage a otherwise stock motor... (2001 nissan frontier SC) is what I learned that little gem from lol .. ran Vp116 race fuel in it.. burnt up my o2 sensors along with a few others in the fuel system... Running pump fuel no matter what octane will not damage anything on a motor unless you are in a newer hp vehicle that requires high test and you run low. Then you could run into problems.

 

The lead in the race gas is what ruins the o2 sensors. 93 will not harm the engine, it's just not necessary. People are looking way too far into this.