Thats another good one.

I would recommend that anyone reading over this thread and deciding to play with fuels and blends, to get a Wideband UEGO and set it up for lambda voltage read out if you intend to mix and match fuels. An EGT would be a wise investment as well, aluminum sublimes at only ~1300*F afterall.

 

Higher flame speeds is related to higher octane and not necessarily to higher ethanol blends only. I wanted to point that out.

 

This is a tired debate that crops up on nearly every automotive forum.

The car was designed to run on regular gas. Go ahead and put in premium if you like, the ECU will compensate. 91 octane isn't "better" gas, it simply has a higher octane rating.

It's your money, spend it how you like. The Fit, in stock trim, is not a performance car. Not even close. There's no benefit to running 91. You'll get more benefit from changing your spark plugs than changing fuel.

Now.......where's my bagel.......

 

No, that is absolutely false. And it has nothing to do with being a performance car or not. The engine is an air pump, it has no consciousness. It does what you tell it.

The Fit was designed to run on a spectrum of fuels. 87 being the minimum acceptable.

If you have nothing of value to contribute, dont bother.

 

Another person that interprets the lowest usable octane as being the recommended grade of fuel that the car is designed to use... Maybe he just didn't take the time to read the owners manual.... Why do non automotive enthusiast keep popping up here?? Trolls maybe???

 

B..b..b but he's an M3 Driver! That means he automatically knows everything in spite of facts and reality. Plus I hear you get a license to drive like an oblivious entitled a$$hole upon signing.

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Do you know how much fun it is to have yuppies in M5s and GT3s try to cut me off on the highway because my current track toy also happens to be an ugly 18 year old car that cost me $600 as a shell with less than $6k invested overall including fuel and insurance?

The look on their faces when I don't even have to downshift = priceless.

Anti-Lag plus NLTS and >30psi are the great equalizers.

Kick the clutch in, slip on the way out as I put the gas to the mat, brings up full spool in a little less than a second (under load in 5th gear) and then they just become a little pair of headlights in the background...

The best part is the Laser is currently wrong-wheel drive while I await some on carrier bearings, subframe pieces and time to swap them in.

 

Troll? Hardly. Non-automotive enthusiast? Wrong again.

Please show me in the owner's manual where it says the car runs/performs better on 91 octane.

To Diamond:

No, that is absolutely false.

What part is false? The part about it cropping up on every car forum? The part about the ECU? The part about 91 not being "better'? C'mon man. Can you be any more vague?

And it has nothing to do with being a performance car or not.

Of course it does. Performance cars typically have a higher compression ratio and require higher octane fuel. The Fit is a car for the masses and was designed to run on the crap gas we have here in the US.

The engine is an air pump, it has no consciousness. It does what you tell it.

Then pull out your ECU and see how long the car runs. You won't even be able to get it started. The knock sensors, MAF, speed sensors, O2 sensors and throttle position all work together to determine optimum timing for efficient fuel burning. The Fit, like many modern cars, can run on a variety of fuels because of this. It's also why you have to have a custom tune if you go FI.

The Fit was designed to run on a spectrum of fuels. 87 being the minimum acceptable.

True statement.

If you have nothing of value to contribute, dont bother.

Just because you disagree doesn't mean you need to get all butthurt Sparky. If you feel the need to spend more money needlessly on 91 octane, have at it. Just don't expect me to sit idly by while you give poor advice to others who may not know any better.

 

I'm being vague because what you need to know is already in this thread, which you clearly did not read.

You don't understand the difference betweens grades or the implications of different fuels.

You have demonstrated that you don't know how a post 1990 ECU works.

BTW the L15A is 10.4:1CR.

You should try sitting idly by.

 

Ahhh......it's very clear now. You seem to automatically think everyone in a car other than yours is an a-h, and you buy into that whole BMW is for jerks nonsense. Good for you Sparky. Do you also want me to lump you in with Honda owners who have those ridiculous purple headlights and useless fart-can exhausts? No, I didn't think so. But, if it makes you feel better to bash someone you don't know, who am I to stop you. This one post speaks volumes about you.

You also seem to have a turbo which explains your need for higher octane fuel.

Street racing? No thanks, that's for fools and idiots. But if you live in NorCal, I'd be happy to invite you for a track day. And congratulations, you can outrun an M5. Do you have any idea how heavy those things are? Not sure I'd brag about that.

 

Post up dyno charts showing an increase in performance with the only difference being the octane rating of the fuel and I'll write a long, heartfelt apology. Heck, I'll even bring you some cookies.

 

Another person that has never taken the time to buy a ticket and take the ride..... Premium fuel in most of the country is 93 octane and California fuel is loaded with additives that most of us have to use the more costly fuel in order to have the same advantages... If you can't afford to spend the money I understand... I would have to ride a moped if things were as costly here as they are where you live. Use whatever octane rated fuel that you want to but don't infer that there isn't any advantage in spending the relatively small difference in price unless you have personally done a comparison before concluding that a disservice is being done by those that have shared the results they have experienced.

 

No where was I racing anyone on the street. I just wouldn't let them cut me off and continue to weave through traffic. I prefer Road Courses and Standing Mile tracks, and I intend to visit Bonneville in the next 18 months I would love for you to join me, thats about as close to CA as I would be allowed in my 1G.

The north side of Chicago is full of expensive cars and shitty drivers.

I was outrunning M5's on the stock 20 year old 34lb/min turbo.

Now I make more peak torque than they do peak HP. As far as being heavy, I will agree to that, but I know my power to weight ratio is superior, they don't seem to take this into account when they floor it to close the gap and hop from the right lane across the middle and try to squeeze between my front bumper and the back of a semi-trailer.

 

Go read the thread. You are in over your head and talking to you will yield no useful information as you have made your conclusions before seeing the facts.


You can eat whatever you want, but I don't expect to sway someone wallowing in their own ignorance.

Edit: Looks like someone has been deleting their posts...

 

Yup, sure did. I misinterpreted your last post, and my response was inappropriate. At least I am able to own my errors, which is why I deleted my post. Glad you got a laugh from reposting it. Hope it made you feel better.

I made my conclusions FROM the facts. You've beat your chest and offered nothing more than anecdotal evidence and hearsay. You'll get a bigger performance boost from running your vehicle in cold weather than you will from running a higher octane than your vehicle is designed for. The only thing you'll get from running 91 in the Fit is a lighter wallet. Again, if it makes you sleep better, have at it, but don't tout it as fact. It isn't. You've made the claim, now post the evidence. Let's see the dyno pulls.

Let's see what some of the actual experts say.

"The Federal Trade Commission, in a consumer notice, emphasizes: "(I)n most cases, using a higher-octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage or run cleaner."
There is "no way of taking advantage of premium in a regular-grade car," says Furey.
"There is no gain. You're wasting money," insists Jim Blenkarn, in charge of powertrains at Nissan in the USA.
"No customer should ever be deluded into thinking there's any value in buying a higher grade of octane than we specify," says Toyota's Paul Williamsen, technical expert and trainer."






And this, directly from Honda, relating directly to the Fit:


"Does it help to use a fuel with a higher octane rating than required in my Owner's Manual?

Refer to your Owner's Manual for the pump octane number recommended for your Honda. Use of a lower-octane gasoline than recommended can cause a persistent, heavy metallic rapping noise in the engine that can lead to mechanical damage.

There is no advantage in using a fuel with a pump octane greater than that recommended in your Owner's Manual."

It also gives and in depth view of Honda's position on fuel additives and oxygenated fuels. You'd do well to read it. It's in Ownerlink under FAQ's.



Now, if you know something the rest of the automotive world doesn't, well, that just cool. Congrats.

 

http://www.toyotapartsandservice.com...-Knock-TPS.pdf I guess the Toyota Guy better reread what they teach their techs.

 

And your point is?? This says that the knock sensor kicks in when it detects pre-detonation. If you put 87 in a vehicle designed to run on 91, this condition occurs, and there is a noticeable decline in performance. That bulletin was written by Toyota (I thought we were talking about Hondas), giving a general overview of how the knock sensor works. Granted, this sensor works pretty much the same across brands, so the same would hold true for the Honda. No argument here. HOWEVER, that is NOT what we're discussing. That bulletin does NOT say that cars tuned to run on 87 octane will develop pre-detonation if using the proper fuel, nor does it say that running a higher octane than the manufacturer calls for (when no pre-detonation is present) provides any benefit to performance. So, to sum: You choose to ignore advice directly from Honda relating directly to the Fit (the topic here), and choose instead to post a 6 year old tech bulletin from Toyota that doesn't say what you claim. Good job. Are you ready for your cookie yet?

 

Great thread. Will read again.

 

It goes to your point, The techs are taught something different than the public. If you want to call Honda and have them explain the ecu and post it I would want to see it. No way is Toyota different than any other car out there, and the differences are small. Here is another link Knock control tables

 

"Granted, this sensor works pretty much the same across brands, so the same would hold true for the Honda. No argument here."


Did you miss that??

In my second post I described how the ECU worked, with almost the same words that the Toyota bulletin used. You then told me I had no clue.

This second link again does NOT say ANYWHERE that using a higher octane than the engine is tuned for provides ANY benefit. IT CLEARLY SAYS THAT THE ENGINE IS TUNED TO A CERTAIN OCTANE, AND IF A LOWER OCTANE IS USED, THE KNOCK SENSOR KICKS IN. The Fit is tuned to run on 87 octane. Geesh, why is that so hard to understand?

Still waiting on those dynos.

 

Now I told you that you have no clue. Selective reading and ignoring the facts sounds familiar. The owners manual says 87 or higher, and doesn't say tuned for 87. I never said the Fit would not run on 87 but if you think it runs the best on it then you dont understand the ecu or premium gas. Heres another link Octane rating - Wikipedia, the free encyclopedia