Sluggish Performance-Octane Rating
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Joined: May 2003
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From: Austin, TX
Sluggish Performance-Octane Rating
I have a 2003 Ford F250 with a V10 and a 4-speed automatic transmission. It has about 5,000 miles on it and it ran great up until about the last month. It seems to be a little sluggish, especially in overdrive. I brought it to the Ford dealer and they said everything checked out ok. The service manager who also happens to have a 2002 F250 V10 told me he only uses premium gas in his truck. He thinks that might be the problem that I'm having as he thinks the 87 octane is just too low for such a big engine. The service manual I recieved with my truck say's to only use 87 octane. Is there a reason not to use the higher octane rating, other than the extra cost? Does anyone else use premium fuel without any adverse problems?
P.S. Thank you to those who replied to my previous post.
P.S. Thank you to those who replied to my previous post.
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Joined: Jun 2002
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From: Central Illinois
Sluggish Performance-Octane Rating
The computer is tuned to run on 87 (unless you have it chipped).
https://www.ford-trucks.com/forums/s...hreadid=101903
On a side note, I was up in Michigan last weekend and filled up with some "economy grade" 86 octane fuel. Driving home, I averaged 15.7 mpg for the tank! I didn't notice any pinging with the lower grade juice.
Matt
https://www.ford-trucks.com/forums/s...hreadid=101903
On a side note, I was up in Michigan last weekend and filled up with some "economy grade" 86 octane fuel. Driving home, I averaged 15.7 mpg for the tank! I didn't notice any pinging with the lower grade juice.
Matt
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From: Jacksonville, FL
Sluggish Performance-Octane Rating
Like Matt said, the engine is supposed to run on 87 unless you have it chipped or have tweaked the CPU with a tuner. I ran mine fine with 87 octane for 20,000+ miles before getting a SCMT. Maybe you just got some bad gas...? Give it a tank or two and see if it evens out. If not, make the CPU re-learn your driving habits.
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From: Jacksonville, FL
Sluggish Performance-Octane Rating
From what I read here and personal experience, it is safe to say a 1/2 hour with the headlight switch in the full-on position, then flip the switch back and re-connect the negative.
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From: Long Island USA
Sluggish Performance-Octane Rating
Going to higher octane than necessary is only wasting money.
Higher octane gas is not a higher quality. The engine will suffer from dimished throttle response at low end, harder starting when cold, etc.
I chipped a '96 t-bird and while it needed 93 octane to keep from pinging, it did start harder when cold, crappy throttle response, etc. This is with or without the chip, so it wasn't the chip, it was the higher octane. Going back to 87 cures it. Saw the same thing with my '97 Cougar. Put in 89 or 93, and it doesn't have the crisp throttle response it usually does.
The higher the octane, the cooler it burns, unless you raise compression. So, using anything more than 87 is not going to do anything for you except empty your wallet faster.
Of course, you may have just gotten a bad batch of gas.
ak
Higher octane gas is not a higher quality. The engine will suffer from dimished throttle response at low end, harder starting when cold, etc.
I chipped a '96 t-bird and while it needed 93 octane to keep from pinging, it did start harder when cold, crappy throttle response, etc. This is with or without the chip, so it wasn't the chip, it was the higher octane. Going back to 87 cures it. Saw the same thing with my '97 Cougar. Put in 89 or 93, and it doesn't have the crisp throttle response it usually does.
The higher the octane, the cooler it burns, unless you raise compression. So, using anything more than 87 is not going to do anything for you except empty your wallet faster.
Of course, you may have just gotten a bad batch of gas.
ak
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From: Broussard USA
Sluggish Performance-Octane Rating
To reprogram the chip just find the ECU fuse and pull that, then you don't lose the radio settigs.
When it comes to octain most people are stupid and think that if you spend more you get more! The truth in advertising thing from the feds made it illegal to imply that you got better mileage and or botter performance from super vs regular! Now when have you heard those guys get involved in anything? So you know how bad the gas companies were lying.
The only time you need to incresae the octain rating is if you have detanation! Or if you increase the compression ratio and timing to take advantage of it.
When it comes to octain most people are stupid and think that if you spend more you get more! The truth in advertising thing from the feds made it illegal to imply that you got better mileage and or botter performance from super vs regular! Now when have you heard those guys get involved in anything? So you know how bad the gas companies were lying.
The only time you need to incresae the octain rating is if you have detanation! Or if you increase the compression ratio and timing to take advantage of it.
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From: Central Illinois
Sluggish Performance-Octane Rating
Originally posted by daimon1054
To reprogram the chip just find the ECU fuse and pull that, then you don't lose the radio settigs.
To reprogram the chip just find the ECU fuse and pull that, then you don't lose the radio settigs.
I disconnected my battery for about an hour while I installed my TB. I never lost radio presets, only the current station. I wonder if that means that I didn't reset the computer or if Ford has taken care of that little annoyance.
Matt
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From: Denver USA
Sluggish Performance-Octane Rating
When gas prices spike (as they are again) I fill up with 85 octane here in Denver. Altitude alows lower octane grades to perform as well as the higher grades at sea level. The last two tanks were 85 and it seems that I am getting better mileage.
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From: Central KY
Sluggish Performance-Octane Rating
For What I know, THe higher octane Gas has less energy per gallon than the lower octane because of the anti detonation additives. THe only thing that High octane does is let an engine take advantage of the power that it can make without detonation. If the engine is designed for 87, 93 is a waste. This stuff is what I found out while working on my pontiac 301 motor. BTW that motor is a POS (8 cylinders, 4 intake + 4 exhaust ports and only two counter weights on the crankshaft)
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From: Broussard USA
Sluggish Performance-Octane Rating
Hope Springs Hauler you and I think the same way! The gas companies will tell you there is not direct coralation in octane rating and stored energy and if you go by the way the test works they are right. But when you look at the fuel it always works out that way.
By compressing fuel say to 9-1 you can use 50% of the energy stored. (made up #'s here) but by compressing it to 11-1 you can use 70%. So even though the fule has less energy you use more of it. You can not squeeze the lower octain stuff because it will detonate.
So in all reality you get better power and MPG running the lowest octain fuel you can.
Now 1 problem is with knock sensors and computer control your truck will retard timing if it detects knock and that will reduce HP. But in this motor it is not a problem running reg fuel.
I drug a 30' 10,000lb camper 3000 miles in very hot weather and never missed a lick.
By compressing fuel say to 9-1 you can use 50% of the energy stored. (made up #'s here) but by compressing it to 11-1 you can use 70%. So even though the fule has less energy you use more of it. You can not squeeze the lower octain stuff because it will detonate.
So in all reality you get better power and MPG running the lowest octain fuel you can.
Now 1 problem is with knock sensors and computer control your truck will retard timing if it detects knock and that will reduce HP. But in this motor it is not a problem running reg fuel.
I drug a 30' 10,000lb camper 3000 miles in very hot weather and never missed a lick.
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From: Long Island USA
Sluggish Performance-Octane Rating
Originally posted by Hope Springs Hauler
For What I know, THe higher octane Gas has less energy per gallon than the lower octane because of the anti detonation additives. THe only thing that High octane does is let an engine take advantage of the power that it can make without detonation. If the engine is designed for 87, 93 is a waste. This stuff is what I found out while working on my pontiac 301 motor. BTW that motor is a POS (8 cylinders, 4 intake + 4 exhaust ports and only two counter weights on the crankshaft)
For What I know, THe higher octane Gas has less energy per gallon than the lower octane because of the anti detonation additives. THe only thing that High octane does is let an engine take advantage of the power that it can make without detonation. If the engine is designed for 87, 93 is a waste. This stuff is what I found out while working on my pontiac 301 motor. BTW that motor is a POS (8 cylinders, 4 intake + 4 exhaust ports and only two counter weights on the crankshaft)
The more octane molecules, the higher the "octane rating". Breaking the octane molecules is hard, so you need more compression or timing advance to take advantage of the power. Compression is the best way to take advantage of higher octanes. Advancing the timing sorta works because you are using other molecules that are more easily burned to raise the temperature in the chamber earlier. Problem is, you are expending power to make up compression to use the higher octane. Sometimes, you loose power. Compression is the only real way to take advantage of the higher octane.
Going to a higher octane gas helps "ping" or "detonation" because it takes longer to get the octane molecules to break. Thereby delaying the actual BANG.
Of course, additives do affect this... up or down.
ak
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From: Austin, TX
Sluggish Performance-Octane Rating
I disconnected the battery for about an 45 minutes so the computer would relearn and then went for about a 25 mile ride. It seems like the power is back (thank you to everyone that suggested this as well as all other suggestions). I've only had my truck for about 5-months and at about 1500 miles, I took it on a 2500 mile trip. I'm wondering if the computer adapted to all the highway miles and needed to be reset. The other scenario, which I hope isn't the case, is that it took several thousand miles for the computer to adjust and that's that's the way it's supposed to drive. I'm keeping my fingers crossed that is stays this because it seems like it's back to it's old happily running self.