@sully963, you mentioned 93 gas. I'm curious. I run my '12 on 87 with no obvious issues (bought it with 170k and have a little under 210k now.). I do get some occasional minor pinging, but it performs well, pulls my 20ft boat with ease, and has plenty of power. I average between 16 and 17.5 mpg depending on driving conditions. I'm interested in knowing how many use 87 vs higher octane fuel?
Unexplained MPG Decline
- Thread starter sully963
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GlennSullivan
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Our 2011 and 2014 5.4 V8s have always been run on 87 and ran fine with no pinging, but I did not tow with either.
Our 2017 3.5 T/T runs on 87 when driven locally and not loaded. When loaded, on a trip or towing we always run on 93.
Our 2017 3.5 T/T runs on 87 when driven locally and not loaded. When loaded, on a trip or towing we always run on 93.
Yep, cause those kind of parts tend to cause alot of issues if other then OEM, and besides, it was only about $15 more than the so-called "compatible with" units..
I've heard too many sad tales of folks that tried to save a few bucks by using 3rd party coil packs, timing parts ect....
DeafBringer
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Octane does not improve or decrease fuel mileage. Octane is not reflective of fuel quality or purity. It is strictly a rating of combustion based on compression ratio. The octane you use should be what the vehicle calls for unless you're experiencing pinging, then go to the next octane provided that the spark plugs, coils, ignition, and compression are all within spec. This is to ensure that the air/fuel mixture does not ignite prematurely and cause damage to the engine.
The same applies for vehicles with forced induction from the factory such as the 3.5l twin turbo. While the Ford 3.5l CAN run a minimum of 87 octane, 91 octane is RECOMMENDED for towing, hot weather, performance, or other severe operating conditions. Some vehicles will require 89 or even 91+ from the factory due to their engine designed around it's compression ratio and using a lower octane than what is required by the manufacturer will eventually lead to engine damage. Also use of an octane lower than what the manufacturer requires can void the warranty.
The Ford 5.4l 3v v8 compression ratio from the factory is set for 9.8:1. Whereas the first gen 3.5l twin turbo v6 compression is 10.0:1 (2nd gen is reportedly 10.5:1?).
There are some great octane rating guides (including youtube), pick your flavor and enjoy! Luckily it is a lot more straightforward and simple compared to what oil you should use...
GlennSullivan
Full Access Members
Octane will improve mileage, but only in engines or engine loads that will benefit from it. The 5.4 3 valve is not one of those engines. However, the 3.5 T/T under higher load conditions WILL and DOES benefit from more octane under these conditions. We have documented this with the 3.5 T/T under towing and heavily loaded conditions.
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