BS. Octane has nothing to do with quality of fuel. It has to do with how quickly it combusts. Octane in modern fuels is probably changed through additives. Whether or not the fuel is "dirty" depends on how it is cared for from the time it is refined.

Most modern vehicles can run on lower octane than specified, but the computer will adjust timing to reduce detonation. This may affect power output, as the vehicle is designed for optimum performance at the specified octane.

 

2000 Civic Si here. high compression for me So Icant run cheap crap. Only premium. 91 Octane is the max here in California.

 

my first fillup (and every one after that) will only be high test for my new baby....

 

Well, that's the point of my thread. If maybe every SI has a knock sensor and will delay timing due to 87 then I'd totally use 87 for daily driving and then fill up on 93 for the weekends or for fun!

I'd like to get a decked out 99 or 00 Si from Craigslist one day, but them maybe my 93 Mazda MX6 LS V6 would be better.

 

YES! Thank you for calling that what it is. You don't get cleaner fuel by buying higher octane.

Jesse, your car probably has a knock sensor. Now if you're looking to save money, keep in mind that when your car retards its timing, your fuel mileage also suffers. How much does it go down? I don't know. It could be relatively little compared to the extra gas you'd be able to buy with the money saved. I'm not actually sure which will save you money in the big picture. I think it's worth testing out, actually. If you do test it, post your results here

 

running 93 octane on a motor that doesn't need it is bad for the motor. It won't burn it all. If you are running a d series put 87 in it. It has less additives and its what your car is suppose to get. If you are running a dohc honda motor then run high octane. When you run high octane in a d series your money is just going out the tail pipe.

 

Actually, I don't have an SI to test it, my 90 SI was gone a long time ago. And my 93 Mx6 LS V6 which require premium but can run 87 - is in Chicago while I'm in Houston.

 

yes your vehicle will run on lower octane but it is bad for the motor. If it says high octane needed and you put lower octane into it. It will actually cause you problems because it is detonating before it is suppose you. Technically you could be losing power.

 

Shouldn't the spark from the spark plug should still ignite the fuel? I don't play around with different types of gas, but I imagine that even 93 octane gas will burn at 59700 celcius

 

Just think what your trying to do. If the people that designed the car say it needs 93 why would you think it would be fine to run 87?
They put that retarded for people that dont know about cars, but like they mentioned before it will just hurt the car in the end