I finally joined FitFreak.net. (also, a question about fuel.)

[deevergote]

And it only took me 7 posts to get someone mad at me.

The topic seems to have been discussed ad nauseum on that site, so I'm going to leave it alone on there. However, the guy (however irritating he may be) presented a point that I'm curious about. I figured I'd ask on here to see what members here have to say.

The thread on FitFreak was about how to get more power with simple mods. One member said to use Shell V-Power gasoline. Now, V-Power is Shell's high-grade gas. The Fit only requires 87 octane, and is only tuned for 87 octane. I'm sure all 117hp is available on 87 octane.
That member said that V-Power is ethanol-free, something I have been unable to verify from any official source (and I do not buy my gas from Shell, so I have never had the opportunity to look at a pump.) He claims that gas that is not 10-15% ethanol, like many fuels in North America are now, would produce more power. There is some merit to that claim... but I don't know how much... nor do I know that V-Power is indeed ethanol-free.


So, since I can be sure to get a more intelligent discussion out of you guys than from that asshat, let me know what you think!

Here's the FitFreak thread I'm referring to. Please DO NOT sign up there to start trouble with this guy. I don't need anyone to defend my honor!
http://www.fitfreak.net/forums/2nd-g...ml#post1100970

[GeoffM]

Isn't it posted on the pumps? Costco says "contains up to 10% ethanol".
You could also ask the attendant.

[bobbycos]

brought a smile to my face !!

[wed3k]

you going to pay for his dyno runs?

[deevergote]

Isn't it posted on the pumps? Costco says "contains up to 10% ethanol".
You could also ask the attendant.

Yeah, but I never go to Shell, except for an oil change!
I do need to get my oil changed tomorrow, so maybe I'll check then. I filled up today with my beloved Wawa gas, so I won't be filling up again until Wednesday morning.

you going to pay for his dyno runs?

Hell no. But if he wants to make claims, and says he's seen it with other vehicles... it's not limited just to the Fit. Any car that is designed for 87 octane will not benefit from a higher octane unless the modifications call for it!

[ChIoVnIdCa]

Well the person who said that lives in Canada so they probably have different regulations on ethanol fuel.

Shell "V power" CONTAINS ethanol in my state and in MOST states. The only way you can buy non ethanol fuel here is at the race track or on a boat dock. Shell doesn't have magic power to sell ethanol free fuel at the pumps against state regulations.

[deevergote]

That's the sort of thing I was looking for!

[evil_demon_01]

OT, but I'm glad we don't have that many ad's on this site!!!!




Your in the right direction Mike.
It won't necessarly make more power with higher octane, but it may be able to make better use of the power.
That is - The peak power won't change, but it could be possible to see power improvements over the revrange, IF there is any form of spark retard (based on knock sensor input) over the revrange on 87. (which is actually pretty normal)

[deevergote]

Wouldn't an ECU that's intended for use with 87 octane not advance ignition timing, or trim the fuel mixture, with a higher octane?

I know some cars, like the Hyundai Genesis (as mentioned in that thread) are designed for higher octane, but will retard ignition timing and use more fuel to combat detonation if a lower octane fuel is used... decreasing power, but allowing the engine to be safely run on lower octane. I don't believe a car like the Fit would be engineered to do the opposite, though.

If it was possible to lean out the mixture a bit, and advance timing, THEN maybe I could understand that happening... but that's not really part of the discussion (though the dumbass I'm discussing with would've been wise to mention it!)

[evil_demon_01]

Wouldn't an ECU that's intended for use with 87 octane not advance ignition timing, or trim the fuel mixture, with a higher octane?

The ECU has no idea what fuel you put in the tank.
The ECU has set value ignition tables and the knock sensor will retard the values as necessary according to knock (along with other variables) - which would be dictated by the fuel used.

Eg even if you put Avgas in your fit, there is only so much advanced timing the ecu can deliver (even if the fuel can handle more) because that is the set stock tables.

[deevergote]

I guess I worded that incorrectly...

If I put higher octane fuel in the Fit, would the ECU advance timing and lean the mixture until just before the point of detonation? I would assume not. I would assume that the engine would run exactly the same on 87 octane as it would on higher.

[evil_demon_01]

If I put higher octane fuel in the Fit, would the ECU advance timing and lean the mixture until just before the point of detonation?

No

I would assume not. I would assume that the engine would run exactly the same on 87 octane as it would on higher.

Correct

[deevergote]

So with that line of thinking, there's really NO way higher octane would increase power in a vehicle designed and tuned for lower octane fuel.

[1badacc]

ive been a member on there for a bit... alot of worthless threads... but i found out alot of good info for a friend

[deevergote]

Yeah, seems like a lot of idiots, but there are a few people that really know their stuff. Like most forums, I suppose. Unlike this place, their cars are only a few years old! Less is known, and the systems are more complicated.