is it good or bad for the fit?

 

I run 87 octane in all of my cars and get great mileage.

 

I dont see why it would be bad ....

 

Higher Octane is a waste of gas. Check the ECO forum for more info.

 

bad. higher octane=slower burn.

slower burn on a boosted or super high compression engine is great because it prevents detonation.

slower burn on a low powered moderate compression engine like ours will simply cause an incomplete combustion cycle in the chamber leaving deposits on your plugs and valves, as well as causing your cat to filter even more unburnt fuel and shorten its life. Gas mileage debates still roar over this issue, but just run 87 unless you go with high comp pistons or boost/nitrous.

 

It ain't bad for the car, but it's probably going to be bad for your wallet.

 

I'd only use premium for high performance cars.

 

agree... not bad but good for your wallet

 

For what it's worth, the Fit ECU does run more ignition advance w/ premium fuel. Doesn't mean it makes financial sense to do so, though. Just means it probably isn't going to hurt your gas mileage any, and it *might* make some more power.

Anyone interested in all the data, search under my user name.

 

Its only bad if the added cost is bad for you. But it will make very little difference in mpg, certainly not for the extra cost.

 

It is bad cuz the rest of the octane that is extra wont burn and will have to evaporate.

 

This is complete nonsense. The octane rating is a measure of a fuel's resistance to detonation. As long as it's unleaded, high octane fuel is neither good nor bad for a Fit's relatively low compression (10.4:1) engine, but it will lighten your wallet faster.

Octane rating - Wikipedia, the free encyclopedia

HowStuffWorks "What does octane mean?"

 

I am not saying it is bad for the engine, i actually ment your paying more for higher octane gas that wont all be used, meaning wasted/Pointless. It will keep the engine clean though.

 

higher octane keeps the engine clean.

 

wikipedia is not a reputable source, nor is howstuffworks. Tell any tech you are using super premium unleaded in your stock or all motor tuned honda fit and they will laugh. All you are doing is spending money that doesnt need to be spent and it is also MARGINALLY detrimental to your engine. It doesn't create enough of a difference that most people would notice but the slower burning nature of high octane fuel causes the mixture in your combustion chamber to be richer and therefore leave more deposits behind on your plugs, valves, and clog your cat faster. The fit burns pretty lean from the factory to conserve fuel so the difference won't be as noticeable as it would on some other cars that burn closer to stoich, but there will still be a difference.

also the theory that higher octane gas cleans the engine is so far from the truth it isn't even funny. If you look on any fuel injector cleaner or fuel system cleaner etc you will see that they use a mixture of many things including diesel fuel (which has a much much LOWER octane rating than regular gas). This is because the hotter and faster burning nature of diesel mixed with the other detergents in the cleaners will burn off any excess deposits left over from the incomplete burn that even regular gas gives.

 

Why? The engine was designed/tuned to run on 87 octane, the higher octane is of no value other than depleting your cash.

 

I did see an interesting post about how using the higher octane fuel causes the ecu to run more ignition advance, which in turn would cause the engine to run with more power and comparable burn rates as regular gas (depending on just how much ignition advance takes place).

I think I'm going to have to do some tests myself with my datalogger and wideband and see what kinds of results I get with regular vs premium. I only wish my local dyno shop hadn't closed down so we could have some solid numbers to run off of power wise. It would be interesting to see whether the ecu can advance ignition enough to actually make it worthwhile to run premium.

 

Really good data would be welcome, although even dyno runs would need some controls, such as draining all the fuel before switching to a different fuel, and trying to make sure that environmental conditions are identical, or nearly so for each run. I strongly suspect that the power differences between regular and premium fuel would be so small that controlling for other variables would be essential.

Fuel economy testing for regular vs premium would be even more problematic. Someone who lives in Florida (relatively flat, with little climate variation) and drives the same route every day would be a good candidate, and even then I would want to see a month of fill-ups for each fuel before coming to any conclusions.

 

It depends. For non-controversial information in STM (science, technology, medicine) Wikipedia has a good reputation. A definition of octane rating falls within this category. Wikipedia's reliability for soft disciplines, and for topical subjects is another matter entirely. Caveat lector.

I've been a librarian since 1972, so evaluating information sources is a major part of what I've been doing for nearly 40 years. A while ago I did a fairly extensive literature search, including both Medline and Wikipedia, for information on bupropion. The Wikipedia article provided the most comprehensive and best sourced (146 references as of 09/09/09) overview of anything I found.

 

Yes that is what i heared from a friend of my who know alot about cars. I learn most of my things from him.