87 vs 93 Octane

[MillstoneF150]

Ran 3 full tanks of 93 in my stock 5.0:
-did not get better fuel economy
-did not feel any better performance-wise
-did not run any better (always had a slight miss or something at idle once in a blue moon)

Anybody else have the same findings as me? Maybe WAWA 93 isn't any good

Looking to get an OZ tune in the near future

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[boy racer]

Not a 5.0 but I've noticed a difference in my 3.5 EB. Better performance and better gas mileage. Also bigger hit o the wallet but the mileage and performance make it well worth it. I'm sure it has to do with the turbo's and the factory programming just designed to run better on higher octane.

 

[powerboatr]

what perfect timing
i just filled up with 29.5888 gallons of 92
i had an .80 cents off a gallon at brookshires and figured i would splurge at 3.19 a gallon vice over 4 for 92.
we shall see if my routine nets any changes from 19.5

 

[JExpedition07]

If you get on the throttle you’ll notice, I am a lead foot. Stock dynos show 330 rwhp on 87 and 350-360 rwhp on 93. You’ll feel that at full throttle. The 5.0L’s 12.0:1 compression to too high for 87 to not pre-ignite, so it retards timing on 87 especially when mashing the throttle or towing. You can run 87 just fine all the time, but there is a power loss factor. It should not affect efficiency, just horsepower.

 

[Graygoose2021]

I always run 91, all we can get in town in my 5.0

 

[SpaceWhiteF150]

I usually run 87 and have great results with it, have yet to try 93. But last fill up I got some E85 and holy smokes it definitely wakes the truck up, but with a loss of about 2mpg.

 

[amschind]

I agree that you should get more out of octane with a forced induction engine than NA. At a very simplistic level, the job of the computer is to "boost to the threshold of detonation". In an NA engine, making those changes requires new pistons, rods or heads.

 

[My 2ND Ford]

I haven't tried 93 myself, I always run 87 because I'm cheap. Price diff is roughly $1.40 per gal. Maybe when I go snowmobiling this winter, I will try a tank or 2 while trailering. 3.5 eco.

 

[JExpedition07]

I agree that you should get more out of octane with a forced induction engine than NA. At a very simplistic level, the job of the computer is to "boost to the threshold of detonation". In an NA engine, making those changes requires new pistons, rods or heads.

12:1 compression is setup for high octane fuel, it’s got the pistons, rods, and heads you are talking about from the factory. It’s retarding the ignition timing on 87 octane, the 5.0 is it made to perform at its best with premium or E-85. There is not an engine in existence with compression over around 11:1 that runs at full power on 87 octane gas.

414 lb ft to the wheel stock on E-85 is a lot different than the 370lb ft at the wheel on 87 octane stock. That’s the whole story on display right there.

 

[amschind]

12:1 compression is setup for high octane fuel, it’s got the pistons, rods, and heads you are talking about from the factory. It’s retarding the ignition timing on 87 octane, the 5.0 is it made to perform at its best with premium or E-85. There is not an engine in existence with compression over around 11:1 that runs at full power on 87 octane gas.

414 lb ft to the wheel stock on E-85 is a lot different than the 370lb ft at the wheel on 87 octane stock. That’s the whole story on display right there.

That makes sense. I guess you can't use the extra power to increase mileage without different gears.

 

[KingDavid]

I got with 87 in there. I only used 93 or e85 after that. There was a big difference in power going to 93. But going to E85; especially now that I'm tuned? Wow. Big smile on face when I get on it a bit and a psychotic grin when I punch it. I love e85. I think the tune is only e40 as well.

 

[Big Dog Daddy]

I've been running 93 in my 5 0, I moved from 87 about a year ago. After the initial fill there was no emedite difference, after about a 100 miles or so with my 36 gallon tank the engine adjusted itself to the top shelf stuff, and you could feel a noticeable difference in power. On long highway trips I've found a slight mpg increase. It went from 21 to 22.5 and occasionally gets close to 23 mpg, and you'll have your foot into it just a little less to maintain 75 to 80 mph. Although the added mpg certainly doesn't justify the additional cost. The additional performance around town is worth it and the engine seems to happily agree!

Edit. I have a 3.31:1 axle ratio in tenth gear at 80 mph the rpm is just under 1750, barely above a fast idle at 80. My previous 150 5.0 had a 3 53: rear and with the 6 speed in top gear at 80 it was running about 2300 rpm. Never got more than 18 mph with that truck using 93 octane.

 

[JimL]

My 2020 5.0 knocks some on 87, but not nearly as much on the good stuff.

 

[Gros Ventre]

After reading much in here on the "Octane Question," I have drawn the conclusion that the engine is designed for 91 octane fuel. An Otto Cycle engine such as this is, cannot extract more power out of its fuel than the octane rating it is designed for. In order to gain the "benefit" of specifying 87 octane in literature and sales, they then used the electronics to derate the engine to run on 87 octane. So will it produce more power on 93 vs 91 octane? No. Will it produce more power on 91 vs 87 octane? In all likelihood: Yes. Would there be a difference in performance of the 5.0L normally aspirated engine vs the 3.5L turbocharged engine for equal power output levels? Yes. But, when designers set out to prevent detonation in a turbocharged engine, they richen the mixture up relative to what a normally aspirated engine would need for the same power output. So the fuel consumption of the turbo engine would likely be higher for the same power output.

 

[JExpedition07]

After reading much in here on the "Octane Question," I have drawn the conclusion that the engine is designed for 91 octane fuel. An Otto Cycle engine such as this is, cannot extract more power out of its fuel than the octane rating it is designed for. In order to gain the "benefit" of specifying 87 octane in literature and sales, they then used the electronics to derate the engine to run on 87 octane. So will it produce more power on 93 vs 91 octane? No. Will it produce more power on 91 vs 87 octane? In all likelihood: Yes. Would there be a difference in performance of the 5.0L normally aspirated engine vs the 3.5L turbocharged engine for equal power output levels? Yes. But, when designers set out to prevent detonation in a turbocharged engine, they richen the mixture up relative to what a normally aspirated engine would need for the same power output. So the fuel consumption of the turbo engine would likely be higher for the same power output.

I don’t think the 5.0 qualifies as your typical old fashioned Otto engine. It can totally change your valve overlap/duration on both the intake and exhaust sides independently and alter ignition timing at the same time to match whatever fuel you are using. This also isn’t considering what the dual fuel injection system can do. It will dumb it down for lower octane, and juice it up for higher octane where it can take advantage and create a more intense combustion event. E-85 certainly puts down more power than 91 octane on the stock calibration, E-85 puts the crank rating of 410 lb ft of torque to the actual rear wheel…that’s a huge jump in twist over E10 91 octane. Livernois and several others have verified this on their dynos on stock baseline runs. Generally E-85 is 105 octane or so, so it will gain more beyond 91. Quite a bit more.

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