Sure it is it is an example of the better efficiency of higher octane. And BTW it has grades just like vehicle fuel 100 up to 115 you can tell by the color.

 

I don't know that you can just scale up or down an engine and say that everything else is the same- engineers spend a lot of time varying all sorts of factors when they do that- as an example when they make an engine a lot bigger they don't double the size of the spark plugs...

Regardless, the data you cite says 91 research octane? Which is 87 in this country? I don't know what the KK and KT models are that that site refers to. Nor what that site actually is. It doesn't appear to be a Honda site, since the email address on it is a Hotmail account.

All we're asking for is some performance data (or something from Honda that says that the engine may perform better with higher-octane fuel). Not a generic "the timing is different so it must be better." I'm not saying I disagree with you, I'm saying show me.

 

Hard to teach someone that refuses to learn Go back and read my posts and try to learn.

Obtuse much that is the repair manual from Honda that he has hosted.

Same engine a whole 200cc smaller LOL. The main thing is the COMPRESSION RATIO is the same. If I have to explain it to you then you know nothing about internal combustion engines.

Performance data is easy READ and comprehend the scan gauge thread and the results using higher octane fuel. It you have to be hand taught the result of increasing timing with higher octane which I tried to do you will never understand.

 

Interesting discussion and perhaps more up to date than what I was told years ago. The next question would be if using the 89 octane plus changes ignition timing etc. and improves efficiency does it give more or less improvement than the ~4% higher price of the fuel.

I'm ready and willing to do the research if someone will sponsor me with a car and gas money.

 

Yes 89 changes the ignition advance over 87. That is covered under the FIT and others using a knock sensor advance until knock is sensed then it retards until knock stops. The reverse happens if you go from higher to lower it RETARDS until knock goes away that it why you have a knock sensor to tune the engine as close to knock as possible.

The most powerful and efficient ignition timing in any internal combustion engine is at the point just a bit before detonation always and forever.

And your friend in the fuel business confirmed this with his statement He also says there is no gain to running higher octane than what the engine needs to run ping free. This is what I said to the point of knock but what he is not taking into account is modern engines VARYING ignition timing so one can gain benifits of higher octane with no manual adjustment the computer does it for you according to the octane used.

It has been tried by members already there is a mountain of of results in all the scan gauge and other octane threads you just have to look for yourself.

In the main better fuel mileage BUT one would have to use scientifically standard testing in controlled conditions to satisfy the naysayers as they don't believe anything. You would have to use the same vehicle on the same course, at the same time, at the same temperature, at the same altitude with certified octane rated fuel yada yada yada which unless you are willing to pay will never happen.

There are just too many variables in fuel mileage calculation to be able for a lay person to objectively say with 100% certainty the differences in fuel mileages just changing octane.

But if one is intelligent enough and has training in internal combustion engines and their operating principles it is easy to extrapolate the reasons why the engine behaves as it does with specific octane.

In the long run this is all VERY BASIC, first year, before even getting to work on any engine, mechanics training stuff and is well known to any formally trained mechanic. Not grease monkeys that learned "on the job".

 

Yes, it makes sense. I may have to experiment with it once I get a car. It won't be the controlled environment of course, but checking say 20 tanks in a row in each grade should give some indication.

 

Gas is still around $3.60 to $3.69 a gallon around here so been running 87 octane no problems and mileage stays around 33mpg combined.

 

LOL LDB only if you drive the same place all the days at the same time at the same speed and get the fuel at the same time of day at the same station from the same fuel load........

See what I mean it's possible to get an idea of trends in fuel mileage good enough for yourself but if you post your results you will get an inordinate bunch of nay saying and replies from everybody on why they think your results are good or bad.

Just look at this and other mileage and octane threads everyone buys fuel and think they are experts because they do. Even worse don't even think about an oil thread LOL.

 

Oh I know there's no way to get fully accurate results. The only thing I will be able to do is to say the average mpg over xxxx miles on 87 octane is xx.x mpg and the average over xxxx miles on 89 octane is xx.x mpg.

Given a large enough grant I can eliminate many of the variables and produce more accurate numbers and am ready to do so as soon as the grant materializes.

 

Insulting the messenger is a time-honored method of changing the subject when you can't refute the data.

Nobody is saying that retarding timing isn't costing performance. We're asking for statistics- some people have posted what they thought was a small improvement in mileage (although others found none) but it usually worked out to be less than the extra cost of premium fuel.

The easiest way to do it is to take two Fits, one with regular, one with premium, race them (a floored automatic would eliminate most differences between drivers), note the difference in time or distance, then switch the fuels and do it again, and get the relative difference between fuels. It's not perfect but it's something.

Telling me "Gee, the gauge shows different timing numbers" tells me that the timing is different, not that it makes any relevant difference.

 

We can argue semantics until the cows come home, but until you can point to a Honda source stating 89 or 91 is either "recommended or required" you're just blowing smoke...

As Brain sez, we don't doubt the physics of more efficient thermodynamics over a greater period the engine operates using higher octane, just that it doesn't matter where the rubber meets the road (or words to that effect).

 

Already ate the steak from the cow that came home... On dessert now (burp)... and the saga continues...

 

Another fit-freaker and I tried to reenact the pepsi challenge with the same car, same driver.

At the time of the ultimate test the over-tuned neon in front of us barfed out its guts and we got bored and went home (It wasn't moving anytime soon after that), never to repeat the test. For what it's worth, the dyno owner stated he doubted higher AKI would make any difference in a Honda. At least he didn't laugh us out of the place.

Here's the historical document from the first pull on premium:


Anecdotally speaking the owner didn't notice any difference running a thousand miles or so on premium prior to this test.

 

That must've been one stringy tough steak...

 

These octane threads almost make me want to go vegetarian... ALMOST!

 

Can we get a HP/Torque overlay off that dyno?

 

well, for what it's worth....



These are two runs the same day on premium. Car was a Sport auto in sport mode/4th. The blip around 95mph I think was the torque converter locking. The dyno-operator couldn't finess HP or Torque as a function of RPM for this car with his software, he had to display the relative speed.

 

What the FTC says on octane:

Paying a Premium for High Octane Gasoline? | Consumer Information

 

Oh so both runs were on premium?

 

I have posted on this stuff before... and I am WAY to lazy to find all the links pics and data again.

Summary is simple though, back in 2007 multiple dyo runs were run in SoCal by the group active at that time. The ONLY thing that made a noticeable difference was running premium AND running a cooler spark plug, a Denso IK-22. This was good for a consistent gain of 2-3 whp even on a heat soaked car. This was on a otherwise STOCK GD.

2-3 whp is not even noticeable. But I did it, swapped to IK-22's and premium (91 in CA) back in Oct of 2008.

Now I have a FlashPro and a ton of other engine modifications so I have no dog in this fight.

Carry on