This might not belong here but I was going to ask to see what kind of answers I get. This not only goes for Hondas but for all cars. Is it bad to run premium gas in a regular gas engine? I know that newer cars have knock sensors and computers and all. But I was still wondering if there would be any damage down the road. This has nothing to do with the price of the gas just the difference. I know one burns longer. I don’t know if it burns hotter. So let me know what you guys think. Is running premium gas bad for an engine that requires regular?? And if so what kind of damage do you think could come out of it?

 

http://www.usatoday.com/money/autos/...emiumgas_x.htm

http://www.consumerenergycenter.org/...s_premium.html

http://www.straightdope.com/columns/...nd-regular-gas

 

No it's not bad. Waste of money, but shouldn't do any damage.

If a car is designed for regular, that means the ECU isn't programmed to take advantage of higher octane. It won't keep advancing the spark any earlier than the map it's programmed with.

Accords (for a while) were unusual in they saw lower MPG with premium gas. Most other cars it made basically no difference in MPG. IIRC that was some late-90s F-series engine.

A car that's designed for premium, will probably get lower MPG if you use regular. That's because it will have a knock sensor to pull back the spark timing (and the boost) & THAT is what makes the MPG go down.

 

Well then I guess it is a tie in that argument. My instructor and I (in a marine mechanic school) were arguing over that point. I was trying to say it matters in premium required cars if you put regular in them that the gas mileage and the performance would suffer. But I also thought it might do some damage because the knock sensor might not be able to compensate for that difference. So it seems that I was wrong, oh well. Thanks for that information guys. I guess I can still learn something new every day. Thanks again.

 

Well, a car that's designed to require premium, will often have higher compression ratio, maybe other little details about combustion chamber shape & subtle stuff like that.

If you use regular the knock sensor *SHOULD* cause it to pull back the spark timing, but it's only got so much authority over engine control. And pulling back the spark timing isn't the same as lowering the compression ratio. Some systems are more sophisticated than others, so I wouldn't say it's COMPLETELY safe for ALL cars.

I was mostly answering the opposite question... putting premium into a car designed for regular.

 

I use 87 octane in my 97 accord, 2.2 liter and have no issues