Well ive heard alot of different things from alot fo different people. But is it true you can get a perfomace boost by using higher octane gas like 93 rahter then 87?
Also is it better for your car at all? Any info would be appeciated.

 

Higher octane fuel is only used if you need to prevent detonation (pinging), lower octance fuels have a higher chance of detonating before it's the optimal time and that will cause a pinging noise of sorts, the only way it's going to gain you horsepower is if you have a high compression engine and then it just makes it run more effeciently.... However, if your car sounds fine and seems to run good then I doubt you'll gain anything from a different octane, but every car is different, the best thing to do is run a tank or two of fuel through it and see if your gas mileage changes and if you notice a difference... run at least 2 tanks of gas through back to back though of the same octane or you're going to have some bad data....

 

is it ture that running higher octane gas will decrease your MPG cause it burns faster [&:]?

 

Not really.... Here's an interesting chemistry thing to wrap your head around.... Higher octane fuel is actually LESS flamable than lower octane fuel (stay with me here...). Fuel flamability is actually tested by how much pressure it takes to ignight (pressure causes heat) and lower octane fuel is fine in a lower compression engine becuase there is not the risk of pre-detonation due to compression so it waits for the spark plug to fire at the proper time.

As far as having to high of an octane fuel and decreasing MPG I've never heard of that..... I guess in an extreme situation where the spark was to weak to ignite/burn off all of the fuel every time that might be true but I'd have a hard time believing that...

 

Flamability can be tested different ways, but ignition temperature comes to mind as the most direct test. That's only kinda sorta related to engine knocking.

Anti-knock testing of a fuel ('octane' numbers) is done in a special engine where they can vary the compression ratio & other things. The result is more related to speed of combustion rather than ignition temperature or ignition energy. Higher 'octane' fuel burns with a slower flame-front speed.

There's an old article in Car&Driver where they tested a handful of cars with different gas. Most cars that were designed for regular gas showed no performance or mileage difference with high-octane. Accord was the only one tested that got WORSE with high-octane. But the difference was pretty small, and it's really only valid for that model, whatever year it was.

 

if you drive any accord before the 2003 model year, it is a WASTE of MONEY to use anything other than 87 octane. IF your engine knocks on 87, you need to find and correct the problem. V6 accords before 2003 DO NOT HAVE A KNOCK SENSOR and therefore cannot advance the timing based upon fuel octane.

2003 and newer V6 accord use a knock sensor and can make sure of higher octane fuel. You get 10HP more but that something you pay for at the pump each and every time and will cost you more the longer you do it.

 

That doesn't count, the tests were flawed. Go back and reread the article.

 

I have to agree with that.. I have a 92 Accord, I put 3 consecutive fillups of 93 octane and the gas mileage went down the crapper, on occasion i will put mid grade (89 octane) and that actually seems to work well but not putting it in all the time.

 

That doesn't count, the tests were flawed. Go back and reread the article.
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I've already thrown it away; what's the story??

As an engineer, I had questions that were not realistic for a magazine like C&D. I didn't know whether they really controlled ALL the variables, and didn't know whether the small effects they reported were within measurement uncertainty or whether they were statistically significant.

 

there is a huge article on the j30a in the v6performance.net forums. They discuss in detail why the j30a does not do well with higher octane fuel... C and D could not figure it out since they were unaware of the limitations of the j30a. You can actually get more power out of the engine if you are willing to tune it to run on higher octane fuel. Honda was very conservative with the tunning of the engine.... J30a could have been a stronger engine if they used 3 stage vtec and slightly larger valves....