I have been following this thread:

https://www.fitfreak.net/forums/eco-...vice-here.html

But really wonder if anyone has a definate answer, with testing results on which type of fuel give the most mpg?

handymus

 

Nothing definitive. But there's a good amount of evidence supporting the theory that the ECU runs more ignition advance on the higher octane fuels. Whether or not that translates into more power, or more net efficiency remains to be determined.

So while premium fuel may garner better mpg, my opinion is that there's not much chance of that improvement outweighing the initial cost of the fuel.

That said, I buy premium now - a couple dollars a month isn't a big deal.

 

I do the same, for now. Just really wondering if it is worth it though. I would really like some data to look at.

handymus

 

if your car REQUIRES premium, run premium. if it it reccomends premium, run regular. if it reccomends regular, run regular.

 

Food for thought.

YouTube - Facts about high octane petrol

 

That video explains a bunch. Thanks!

Looks like our Fits can't really take advantage of the premium like a higher compression car could.

handymus

 

No problem. Glad to help people save some money at the gas station. However, I still fill up with supreme at Chevron once a month. The rest of the time it's all Chevron regular.

 

You may not want to make that assumption so quickly . . . search for "ignition advance" and my screenname, and you'll find my thread with LOTS of data to look at.

But again, ignition advance equaling more power on this car has yet to be demonstrated.

 

Show me the data.

 

..........

 

Unless I missed something, your datalogs were with the first generation Fit. Your recent post sums things up:

I've seen nothing to indicate that running premium fuel in an engine designed for regular does much more than empty your wallet faster. If I had a blown Fit, premium gas would be an entirely different matter.

 

I thought I was getting about 3 more MPG when I used premium compared to regular but I'm not. The last fill up I put in premium and only got about 1 more MPG. For me, the extra $$$ spent isn't worth it.

 

Was that under debate? Noone's been talking generation in this thread. You asked for data, so I assumed you were looking for data that supports the only claim I've made. :shrug:

Well that's the crux of the matter - if the ECU runs a different tune on the more expensive gas, can we really say that it was only "designed for regular"? Obviously, it's perfectly capable and safe to run on regular - but (to my surprise when I discovered it) all evidence points to a more aggressive tune with higher octane fuel.

And even without knowing whether that advanced ignition timing translates into more power or mpg, I'm saying that an extra 3 dollars a fillup is a financial risk I'm willing to take.

 

That's cool that you got more mpg with premium. I actually lose anywhere from 2-5 mpg with premium. I think it has to do with my granny style driving. I've heard that those who drive like me will see loss in FE with premium, and those who drive their cars hard will see an increase.

 

The Fit does not run timing advance with premium fuel. It doesn't have a fancy pantsy fuel type detector. It would only pull timing if it senses knock, like most cars. Since this is the case, premium fuel would only decrease MPGs since it has less energy than regular. Premium is more stable, good for high comp and forced induction. It's more expensive because it has more additives to be more stable and remove deposits.

 

Have you read the thread?

 

Yeah, seriously. I own a device which shows me timing advance--it's a ScanGauge II--and it indicated the ECU was putting more advance with premium. I logged my best tank this year running premium. I also ran some average mileage with premium. I don't seem to save much running 93 octane, but I can tell the difference in torque, so I'm using 93.

 

i clapped my hands 3 times before i got in my car every day last week, and i got the highest mpg on that tank than ever before. so now i'm going to clap 3 times before every drive to get better mpg. sike.

you will need a lot more statistics involving temperature, drive distances, road conditions, traffic, and like one hundred other variables before you can even start to make a credible claim that running a higher octane got you a higher mpg. if you had someone fill up your tank without telling you what octane they used, i am very skeptical that you can feel the torque upon acceleration and tell them if they used premium or regular.

 

I think you forgot to read the 4th sentence, as well as the first part of the 5th one, in my previous post.

 

touche haha. most of it wasn't directed at you really, but your post just initiated me to make a post explicitly stating some things. simply because i see people posting claims all the time and i think some people read the posts and are gullible enough to believe anything. you're right, you didn't really claim some of the things i was pointing out, but i just thought it implied some things that i wanted to give my thoughts on.