My neighbour and I both have Jayco Greyhawks on Ford E450 chassis.The same engine, the 6.8L ford engine.He insists on using high octane fuel, probably octane 94.I was considering using octane 87, which is what the book says.Any opinions on this would be appreciated.My unit is a 2008 while his is a 2012.I just purchased mine a few days ago hence this question came up.Many Thanks

Follow the manual... I have since my first V10 in 1999. I tried higher octane and could not detect any difference in performance or milageIn fact follow on maintenance also, Ford designed the thing and know it better then 99.999% of all backyard gearheads.

Your neighbor is wasting his money on fuel.

Mine is a 2005 with 39k miles on it and have always used 87 octaneand never any issues.

n7bsn wrote:Follow the manual... I have since my first V10 in 1999. I tried higher octane and could not detect any difference in performance or milage.I totally agree, when we had our 2001 E-450 I did the same thing and the only thing that improved was the gas stations profit.

I was a Ford tech for 25 years.These engines are designed for low octane fuel.The high octane fuel is "slower" burning. This will actually create carbon deposits in the combustion chamber.These carbon deposits will flake off and jam a valve open causing engine damage.I have seen it happen several times.

A question on fuel for a E-450 ford chassis | Good Sam Community

18 Replies

carringb
Explorer
Jun 19, 2013
tatest wrote:
I sometimes buy 89 or higher octane when it is cheaper than 87 octane (a supply and pricing quirk that happens more often than you might imagine), but notice no difference in mileage or performance.
.

Anytime I've seen cheaper 89 octane its because its ethanol-blended, while the 87 octane is not. Running empty I see better fuel economy with non-ethanol fuel but when I'm towing heavy its doesn't seem to matter (maybe the higher octane mitigates the efficiency loss?).
tatest
Explorer II
Jun 19, 2013
I sometimes buy 89 or higher octane when it is cheaper than 87 octane (a supply and pricing quirk that happens more often than you might imagine), but notice no difference in mileage or performance.

Ford says 87 octane is good enough for the 6.8 V-10, that's what the fuel and ignition timing maps in the ECM expect to be dealing with.
gotsmart
Explorer
Jun 19, 2013
Home Skillet wrote:
I was a Ford tech for 25 years.
These engines are designed for low octane fuel.
The high octane fuel is "slower" burning. This will actually create carbon deposits in the combustion chamber.
These carbon deposits will flake off and jam a valve open causing engine damage.
I have seen it happen several times.

X2. I had a 1995 Ford Ranger XLT 4.0L (that had a rear axle recall). In 1995 the service dept at Nashua Ford (Nashua, NH) told me to use regular unleaded and to add a bottle of Gum Out in the fuel tank every 4 or 5 fill-ups or so.
dsurette
Explorer
Jun 19, 2013
I usually run 87 also, but on a trip out west last year the regular was 85 octane in the higher elevations. Supposedly in higher elevations can run ok with lower octane. Well my E-450 noticed it and didn't like it. I switched to mid-grade and things seemed back to normal.
carringb
Explorer
Jun 18, 2013
I'm running a DiabloSport Predator on the 87-Performance tune, plus some additional custom changes to the tuning for even more power. I still run 87 with my trusted brands (Chevron/Texaco, Safeway, Fred Meyer), but I am so close to the edge that some other-brands will cause pinging so I do occasionally spring for 89.
j-d
Explorer II
Jun 18, 2013
x2 on the Chip or Tune. Without one of those, no need to up the octane. And some Tunes take you to what they consider max for 87, then tell you higher is required for the higher versions they offer.
mlts22
Explorer II
Jun 18, 2013
Only time I have seen people use higher octane fuel is if they have a custom tune, and have timing changed so as to require the higher cost gas.

I just use the cheap stuff, and so far, so good.
wbwood
Explorer
Jun 18, 2013
Home Skillet wrote:
I was a Ford tech for 25 years.
These engines are designed for low octane fuel.
The high octane fuel is "slower" burning. This will actually create carbon deposits in the combustion chamber.
These carbon deposits will flake off and jam a valve open causing engine damage.
I have seen it happen several times.

What I've always heard.
GilONel
Explorer
Jun 18, 2013
Thankyou guys for all your posts and input.
I'll use regular 87 octane.
Dusty_R
Explorer
Jun 18, 2013
He IS getting some advantage from it. He feels better and his wallet is lighter.

Dusty