Go Figure. I guess the obvious it too hard for people to understand. The lower the octane without pulling timing = more power and better mpg. You want to run the lowest octane possible. The only reason to go to higher octane is to slow the burn when adding high boost levels + timing to prevent detonation. If there is no detonation with a lower octane there is NO reason to run higher octane. Period.

Go buy a Ecoboost and dyno it. Once on 87 and once on 91. Show me the proof. Internet racing don't quite do it for me.

And as my original statement goes... if it's not pulling timing, you are not going to gain anything. Want to argue that??

Do you even know the a/f ratio on the F150 Ecoboost? Oh wait, that's right... you don't own a Ecoboost F150.

 

All I know is my 2010 Camaro SS the cheap bastids at the dealer put 87 in an engine designed for 91 after a service. It put the car into safe mode cutting it way back on power because it detected the knocking and was not remedied until they reflashed the computer.

Here is how I feel, the boost pressure on the Eco truck motor vs. the SHO Eco is most likely lower due to truck vs. car . In the summer any engine knocks more especially when pulling a trailer due to ambient temps and load. For most driving around town, I'll put in 87, but on a long trip pulling a trailer I'll feed my baby a better diet of 91. Being an ex-boat racer used to 500 inch Big Blocks, I know detonation or knocking of any kind rattles the hell out of things and is not good even for a milisecond. But I trust the computer in the truck for everyday driving and think 87 is fine even in Phoenix

 

Did you think that maybe the boost and timing are increased on higher octane, thus making more power? You said yourself, that is how more power is made, so maybe that is what Ford is doing? So, let's just say for a minute the EB is tuned for 91 octane, where it produces 365+y hp and 420+z ft-lbs torque. When it runs on 87 octane, it produces 365 HP and 420 ft-lbs. Timing is being pulled and boost dropped to accommodate the lower octane. Why is that so hard to comprehend???

No, I don't have an EB...the F150 isn't big enough for our fiver or I probably would. Personally, I don't care what the a/f ratio is, and I don't need to dyno it...I'll take Ford's word for it over yours. As I said before, I will trust a multi-billion dollar company (producing cars no less...something they should know something about) with a tremendous engineering division over you (an internet car tuner).

Since you seem to be the only one here disputing what Ford has said, why don't you buy an EB, dyno it on 87, then run a few tanks on 91 and dyno it again. Maybe you can prove us all wrong...even Ford!

 

On the freeway 70 MPH, but I have 20" wheels and 3.55 LS rear.

As far as additional power with premium I know for a fact that you get 15 hp and at least 15 torq from the 93 octane. I understand what Oldschool is saying but these new computers monitor knock and add timing appropriately. So if you are running the cheap stuff you will not get as much timing, switch to the good stuff and the computer will advance timing until it knocks then back it off. It samples million times a second and is always changing the timing. It is one of the nice features of electronic Variable timing.

 

Interesting thought process, when I was racing Big Block Chevies in boats, we put as much lead in the timing as you can as you can without blowing the thing up, because thats where the optimum power was. We ran our 500 inch methanol motors with 14.5 to 1 compression with 38-40 degress of advance, sometimes take it to 42 if the air was thin due to altitude and it was runing rich.

As for adding power by increasing octane on these new fangled Eco motors, I doubt the Ford computer will add enough advance and boost to net you 15 more HP, I agree with the "internet tuner" on that one

 

I own the truck. 91 isn't going to do squat. The only thing it might help is prevent ping while driving in the mountains/high altitude towing 8,000lbs on a 90+ degree day.

As far as what the original post is about - gaining MPG from higher octane = not going to happen and a waste of money.

As I said before... show me a dyno showing a 15HP gain or TQ from adding 91 and I'll eat my words. But until then.... silence!

Side note: I'll be one of the first people to have a tuner from SCT when they release one. If not, there are a few old school turbo tricks to add boost without tripping any kind of computer codes or throwing over-boost shutdowns - a.k.a "limp mode". Been there done that.

 

OK, last time and I am done with this, sorry for those of you who are annoyed by this but here goes, it seems an inside engineer says the computer will 'test' fuel and add timming and add boost depending on fuel ratings. That would make sense seeing that the guy that has a boost guage says he sees about 11 lbs, and I know these motors make 13 lbs. So take it for what you will and if I am wrong I will gladly eat crow.

http://fordflexforum.com/index.php?/...ompared-to-87/

"Well I can tell you my info, or I can tell you my source, but not both!

What's special about Ecoboost is the COMBINATION of turbos and direct injection. As you pointed out, old-school turbo engines required very low compression ratios in order to avoid detonation. But direct injection provides a cooler fuel charge, which helps prevent detonation. So essentially you can add more boost with direct injection than without it.

Basically Ford has used direct injection to offset the lower compression ratio requirement, thus an Ecoboost engine runs about the same compression as a normal naturally aspirated engine. But detonation is stil the main thing that holds back the amount of boost that can be safely run, and higher fuel octane can prevent detonation. So yes, the engine computer is smart enough to know when [what] kind of fuel it's running (as they have been for many years already) and can thus adjust the boost and timing accordingly.

You can get a lot more benefit on an Ecoboost engine by running higher octane fuel because the computer has both the boost and the timing to take advantage of, whereas a naturally aspirated engine will only be able to optimize timing."

 

Bottom line, if I feel like the truck runs better on premium and has a slight increase in mileage, I'm going to keep running it. If I dont, I wont. It's my money to waste, not yours

I'd be interested in getting a tuner as well. Now thats a way to gain some extra power without an online debate, ha.

 

Can't speak to the 3.5 but the FORD MANUAL claims a PERFORMANCE increase using premium in the 5.0. Unlike the 3.5 it does not stipulate severe duty as towing or heat being the environment in which a performance would be realized but that performance in general would be realized.

 

The Ford manual says premium fuel will provide "improved" performance for the 5.0. For EcoBoost they do not say improved performance but BEST OVERALL performance. They said "BEST OVERALL" performance using 91 or higher. Best as in the most advantageous and overall as in INCLUDING EVERYTHING.

They say it will be most noticeable during towing or heat. This does not mean it won't be noticeable elsewhere. And since they say BEST OVERALL that means EVERYTHING, not just towing or hot weather. For the 5.0 they do not stipulate best overall or 91 or higher. They just say improved and premium, whatever that means.

http://www.motorcraftservice.com/pub.../11f12og2e.pdf

 

Would you take the word of a Ford engineer?
After Mike at Pickuptrucks.com got bashed for not using premium for his towing test, he posted the following:



"The official response from Ford about using regular fuel for the EcoBoost test: "It is true that you would have had improved performance and fuel economy on premium, but to your point in the comments, we do our EcoBoost
ratings on regular fuel."

FWIW, I've recommended to Ford that if other journalists are going to tow heavy trailers for their road test, that they use premium.

 

From everything I've heard, EcoBoost owners have been getting more power from the higher octane.

 

Going back to my original post, I have burned about half a tank of 93 octane so far.

Trying to be self aware of the placebo effect, here is what I've noticed. The engine seems to idle a bit smoother, and go through the rev range smoother. There are no obvious power gains. My last tank averaged 14.8mpg on 87 octane and, so far, I am at 15.6mpg on the 93 octane tank. I realize there are hundreds of variables with this kind of test, but just thought I'd share what I've observed thus far.

side note: It's been about 97 degrees most days here in south texas.

 

Man that was what I was waiting for. This is your experiment for crying out loud. I would live to see you make the mpg that you are looking for with premium fuel. But if you don't, oh well. You did the experiment and have educated all of us on the real world results. That's the point of this, right? I say damn the torpedoes. Who cares what anyone else thinks, let's see some results and all get educated based on that! Great idea on the experiment here and I hope it works well for you. Tell the other crying babies to grow up.

 

Amen to that!