mileage question
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Joined: Nov 2000
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From: omaha nebraska u.s.
mileage question
have heard that from the factory. computers in certian f-150 are set to run better on 87 vs 92+ my questionis. in less that 2 weeks i will be driving from here in omaha to vegas in my 97 4.6 sc 4x4. regarding mileage. will i be better off running 87 or 92. and is my computer set up for the lower octane? any help will be greatly appreciated.
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Joined: Mar 1998
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From: Virginia
Hi felixx695,
As long as your are running the factory program, it's basically a waste of money to run anything more than 87 octane, as that is what it is tuned for from the factory, and that is true of all these non-Lightning F-150's, not just some of them. The factory program does not have the ability to properly take advantage of premium gas. All it can do, if you run it on premium gas for 1500-2000 miles or so, is give you a maximum of 2% more power, which for your 4.6 means a maximum gain of 4.4 horsepower. It cannot increase spark advance sufficiently to see a true gain in mileage that would make it worthwhile for you to use premium gas instead of regular.
The fuel curves in the factory program are calibrated for the considerably quicker burn rate of 87 octane fuel; when you run it on premium, though it will hopefully run just fine, it will not have the best driveabiity it could have if you just stuck with the regular gas it's calibrated for, because the fuel curves are calibrated precisely for the burn rate of 87 octane gas. Premium gas burns slower, and so the fuel curves must be re-calibrated for that different & slower burn rate for proper driveability.
In fact, most owner's manuals for these trucks will tell you specifically *not* to use anything more than 87 octane gas, and this is exactly why, the different burn rate, because it can actually cause driveability problems, in some cases, as the motor "lays down" when the burn rate of the fuel is too slow, as it is when using premium gas with the factory program. We've seen that happen and had a number of people post here that this happened to them; we've seen cases of less power, worse mileage, & of course worse driveability when using premium gas with the factory program in these F-150's. Please understand that I'm not saying that happens *all* the time of course, but it can & does happen often enough to be a consideration for Ford, and that is why the owner's manuals for most of these vehicles tell you to use only 87 octane.
I hope this helps a bit, & have a good trip!
------------------
Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer
[This message has been edited by Superchips_Distributor (edited 03-22-2001).]
As long as your are running the factory program, it's basically a waste of money to run anything more than 87 octane, as that is what it is tuned for from the factory, and that is true of all these non-Lightning F-150's, not just some of them. The factory program does not have the ability to properly take advantage of premium gas. All it can do, if you run it on premium gas for 1500-2000 miles or so, is give you a maximum of 2% more power, which for your 4.6 means a maximum gain of 4.4 horsepower. It cannot increase spark advance sufficiently to see a true gain in mileage that would make it worthwhile for you to use premium gas instead of regular.
The fuel curves in the factory program are calibrated for the considerably quicker burn rate of 87 octane fuel; when you run it on premium, though it will hopefully run just fine, it will not have the best driveabiity it could have if you just stuck with the regular gas it's calibrated for, because the fuel curves are calibrated precisely for the burn rate of 87 octane gas. Premium gas burns slower, and so the fuel curves must be re-calibrated for that different & slower burn rate for proper driveability.
In fact, most owner's manuals for these trucks will tell you specifically *not* to use anything more than 87 octane gas, and this is exactly why, the different burn rate, because it can actually cause driveability problems, in some cases, as the motor "lays down" when the burn rate of the fuel is too slow, as it is when using premium gas with the factory program. We've seen that happen and had a number of people post here that this happened to them; we've seen cases of less power, worse mileage, & of course worse driveability when using premium gas with the factory program in these F-150's. Please understand that I'm not saying that happens *all* the time of course, but it can & does happen often enough to be a consideration for Ford, and that is why the owner's manuals for most of these vehicles tell you to use only 87 octane.
I hope this helps a bit, & have a good trip!
------------------
Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer
[This message has been edited by Superchips_Distributor (edited 03-22-2001).]