I ran 91 octane here in denver for about a year in my brand new v-10 ! I have read all over the place to run 87. Should I be concerned with any engine damage that I may have caused. Ihave had no problems with yet at all I am just wondering!
thanks for the help all!
and I did switch to 87.

 

I think the only damage would be to your wallet.

 

I always use 89 octane...........I don't care what others say. In all three of my vehicles i get BETTER fuel mileage with 89 rather than 87........87 is the MINIMUM, get a bad batch of it and it could be 84 or 85...........my Mercury outboard runs best on 91 even though 87 is recommended.............ask others why the companies make 89 and 91 octane............there is a difference .

Dan / FT

 

Always use the lowest octane rated fuel you can without excessive engine knock. I worked for an oil company for many years. The extra additives, to reduce knock, will only gum up your fuel system if you don't need them.

 

Fishin-Technician- The reason that gas companies produce 89 and 91+ octane deals directly with the type of engine that you have...ie amt of compression. The higher the octane, the higher the flashpoint. You would want to run a higher octane in a higher compression engine. The V10 is NOT a high compression engine. And theoretically, as you go higher in altitude, you could use even a lower octane. The combustion pressures are lower at higher altitudes. The less air that is being compressed, the lower the combustion temps are as well. A HIGHER octane gas has LESS BTU's per gallon, which also means that using a higher octane will result in LESS power. So there is NO reason to run anything higher than 87 in the V10. I actaully had my truck in at the dealer for a complait of loss of power (caused due to ALT...DUH!), and their first question was "what octane are you using?". There is no octane sensor in these trucks, so the compuer has no way of adjusting for the higher octane.


Just my $.02

FLYINFORD

 

I think the official manufacturer's line is that running higher octane than necessary can lead to carbon buildup because of less-than-optimal temperatures. Higher octane runs cooler. It also affects emissions.

I have found that here on Long Island where the temperature swings from (lately) below 10F in winter and above 100F in summer, that higher octanes run cooler and the car just doesn't warm up as fast and responds like it's lean. In warm weather, it's OK.

I have a '97 Cougar 4.6L that I run only 87 in. I have a '96 t-bird 4.6l that I have to run 93 in because of the SuperChip. The '96 doesn't like to start up as easily as the cougar in the cold, but only when I use 93 octane with or without the chip. The compression ratio should be higher. In my V10 I run only 87 octane, and between two different gas stations there is a marked difference in flat-out performance and drivability between the two. One is good at 3000 RPM, the other starts up and idles better and gives better off-idle response. The one that is good at 3000RPM is probably a higher octane than the pump rating.

I saw a documentary on the History Channel or somewhere lately that was about oil refining, mostly gasoline. It turns out that most gasoline is piped around and they are common-carrier. Mobil, Exxon, BP etc all put their refined product into the pipelines, they mix in transit and they each take out as much as they put in at the beginning. Only locally do they add an additive package that adds detergents and other things like MTBE that is required here in NY Metro (soon to be banned because of it's affinity for drinking water). We have some refineries around here, so there may be some direct brands available here, but in, say, the Mid-West, there is probably a lot of homogenuity. Had a gasoline barge explode while filling docked at Staten Island recently...

BTW: "Octane" stands for the 8-molecule ring-shaped molecule found in gasoline. The more "octane" the higher the octane, so to speak. The ring-shaped molecule has a higher number of molecular bonds that are broken, releasing more energy. But it's harder to release and you need more compression to get there. Without an increase in compression or spark advance, increasing the octane is useless (theoretically - it has it's advantages in hot weather and there is plenty of anecdotal evidence to the contrary).

Sorry for the long-windedness, I am tuning databases tonight and there is plenty of dead-time waiting for things to complete

art k.

 

I have to run 89 octane or it's starts pinging... $1.54 a gal..

 

For best power, run the lowest octane that your engine runs well on (does not knock of ping).

Higher octane means harder/later detonation. Too high octane is exactly like retarding your timing as far as the engine is concerned.

-Jim

 

If anyones V10 pings on 87 octane, they should probably take it in and have it checked for codes.

More power to anyone that claims better fuel mileage on 'premium' fuel.

Higher octane fuels are for higher compression, higher performance engines, and chipped ECM's, anyone else who feels that they don't pay enough for gasoline!

(formerly 3992824)

 

If you want even more of the octane issue do a search of this forum and teh Superduty forum in the last 90 days there are several similar threads

V10 loves 87 octane and if you have problems with pinging/predetonation then first change brands to Chevron with Techron, if that does not work then get it to a competent technician as the V10 is a low emmissions vehicle certified by Ford to run on the cheap stuff. And the emmissions warrenty is a lot longer than 36/36K

I will admit that I run 89 when I am on a long trip, going fast, with my heavy TT load, and I get lower engine temps and better MPG with the mid grade. I notice no improvement with mid grade for daily driving thus will not waste the $$$.

 

In case some of you guys missed the point, regular unleaded here in Colroado is 85, not 87 octane. You can do that because of the thin air.

This is an interesting question because the owner's manuals for BOTH the 2000 F-150 5.4 I used to own and my wifes 2000 DOHC Focus, like HIROLLN's manual say to use 87 octane, even in high-altitude areas. That would be mid-grade fuel here. I even use 85 in my 460 wthout issue, and I've got the timing really advanced on it.

I've always used the local 85 octane regular in the vehicles that are supposed to burn regular 87 octane at sea level and never, ever have had a problem or pinging. That is, unless I filled up in Denver and headed down to lower altitudes in Kansas or Nebraska, then there'd be a little bit of pinging until I filled up with the local fuel.

I think the immediate answer is, if your truck runs fine on the 85, keep using it. Don't worry about it. But the more interesting question is why does Ford say to use higher octane fuel than what you really need around here, when everyone else, regardless of vehicle brand and millions of miles driven is having no problems?

------------------------------------------

2002 F-250 S/Cab Short Bed PSD 4x4. SCMT +80 HP, AFE Magnum intake, Magnaflow 4" exhaust.
1996 F-250 S/Cab Long Bed 460. E4OD auto, 4.10 posi, Air-Lift suspension, K&N filter in modified intake box, modified ignition advance curve, Edelbrock 2x61 mm throttle body, L&L 4 into 1 headers, milled heads, 3" exhaust system, cat & Flowmaster 70, modified MAF meter. 7,700 lbs GVW, 5,700 lbs empty.
{E\...F}

 

What are some things I can check for to resolve the pinging? The last thing I want to do is take a chance with the dealers around here! I'm at 87k and thinking about changing the plugs. Should I change the O2 sensors? What else?

 

Regarding Paarrothead's post on using 85 Octane fuel at altitude, has anyone done this with a V10?

The only vehicles I've tried the 85 in were a 1990 GMC with a 5.7/350 and a Dodge Neon (can't remember the year). Both pinged on 85. The Neon would ping on 85 if it was in gear the and A/C was running... granted, it was a Neon.

I've been afraid to try it on the V10.

 

My owner's manual for my E350 V10 says to avoid using anything over 87 as it may cause "rough running".

My van likes 87 just fine, even when fully loaded. My MPG seems constant in the 10-12 MPG range regardless of speed or load.

(note, 3.73 gears and cruise fitted)

 

I live here in Colorado and run only the 85 octane fuel. I have a '99 F250 CC SB with a K&N FIP kit , <a href="http://www.motorhaven.com/">Hypertech</a> III computer and Gibson Cat back system. I have never any detination or other problem with running the 85 through it. It runs like a striped monkey. Never had any problems towing my trailer with my race bike and spares in it.