3.5 Ecoboost - What type of fuel are you running?

[peterk9]

Hello,
Just took delivery of my 3.5 eco-boost explorer premium Saturday. In the past I've always had supercharged Mustang Roush, SVT, etc. and had to use premium fuel. I can't see that Ford recommends premium fuel for this TwinTurbo engine what do you guys use?

Omar, the opinions here are like those regarding when to change your oil. My suggestion is to try running a month or two on one and then the other and judge for yourself which you prefer. You can't compared running an Ecoboost (EB)EB on 87 octane to a normally aspirated 3.5L as being in the same ballpark is on regular to that of a regular 3.5L V6. Like the Manual says, the recommended fuel is 87 octane. But if you feel that top performance is what you want, then by all means use premium. But comparing a normally aspirated 3.5L to an EB on 87 octane a non starter for me. I'd be very surprised if moving to premium is going to increase the HP by 75 and the torque by 95 ft. lbs. I noticed no such difference. The difference in cost today between 87 and 94 at the station I just filled up at was 96 cents a gallon (Cdn figures).

Peter

 

[dora51032]

i'm running 95, there are only 3 octane available here 91, 95 and 98
i've tried the 98 but didn't noticed any difference.

 

[expoman55]

My 15 EcoBeast is tuned and delivers 345 HP. I am consistently getting 20-21 around town and 22+ on trips

it is a beast and I burn 93 at ALL times.. what i find is that after a few thousand miles of around town I need a long trip.. Following that seems to be even quicker .Maybe my imagination..

 

[peterk9]

My 15 EcoBeast is tuned and delivers 345 HP.

The advertised HP with 93 octane for a non tuned Ecoboost 3.5 is 365. How can you get 20 HP less with a 'tuned' engine?

Peter

 

[seanmclean]

The advertised HP with 93 octane for a non tuned Ecoboost 3.5 is 365. How can you get 20 HP less with a 'tuned' engine?

Peter

Advertised HP and what is actually delivered to the wheels is very different.

 

[613GT500]

The advertised HP with 93 octane for a non tuned Ecoboost 3.5 is 365. How can you get 20 HP less with a 'tuned' engine?

Peter

HP/TQ ratings are at the crank. Real world output measured at the wheels on a dyno is less. I watched a few dyno runs on a stock 3.5EB and the hp was close at about 330 or so but tq was just shy of 300.

 

[Fentress24]

I have tried both. I ran 93 for the first 5000 miles after I first bought the truck to be safe. I switched to 87 after that and really didn't notice a change at all. I felt very little to no performance decrease and I am averaging 19.5mpg. I will switch to 93 when I get a tune, but the extra .50+cents a gallon they charge for 93 around here is ridiculous and not worth it in my opinion. The extra 50+ hp from a 93 octane tune is definitely worth it!

 

[bdginmo]

Since my wife drives the Explorer most of the time it gets 87. I haven't tried a higher octane yet.

I did a lot of research on how the stock ecoboost engines dynamically tune themselves so here's the cliff notes version. They start with a base set of timing values and adjust them by an octane adjustment ratio or (learned octane ratio). This OAR can float between -1 and 1 with 0 being the base value. Because of how the tuning table and OAR work together a negative/positive OAR equates to advanced/retarded timing respectively. The ECU will use the knock sensors (and possibly other inputs) to drive the OAR as far as possible towards bigger negative values (advanced timing) while still preventing knock. A value of -1 is the most desirable. This seems to be pretty well known.

What isn't as clear is the strategy it uses for dynamically changing the OAR. But based on forum posts I saw there may be both short and long term learning cycles. The short cycle apparently adjusts very quickly to knock, like when dropping from high octane to low octane fuel on a fill up, and uses a + adjustment to the OAR to prevent the knock in a reasonable amount of time, but the - adjustment to the OAR takes a bit longer. One forum post claimed the + adjustment can happen as quickly as a single WOT accelaration, but the - adjustment may take several miles.

There may also be a long term learning cycle in which the timing adjustments are stored in a semi-persistent memory area of the ECU and may take more than 1 tank of gas to fully adjust. If you have seen the claims about running a certain octane for several tanks before drawing conclusions then this is likely where this originated.

So from what I can tell the EcoBoost engines will respond very quickly to lower than expected octane and somewhat quickly to adjust to higher octane fuel. But, a fully adjusted tune may not occur on the first fill up.

If someone has something to add or correct then please chime in!

 

[Mlim_556]

93 always

 

[Fentress24]

I bumped to 93 around early December due to winter gas and have noticed the truck runs better. I will continue to run 93 going forward.

The truck runs just fine on 87, but it is definitely happier with 93 in the tank.

 

[peterk9]

I bumped to 93 around early December due to winter gas and have noticed the truck runs better. I will continue to run 93 going forward.

The truck runs just fine on 87, but it is definitely happier with 93 in the tank.

Saving around 96 cents/gallon (CDN) using 87 makes me happier and that is the important part.

Peter

 

[613GT500]

Still running 91 octane at $1.07/L ($4.00/gal) and enjoying every moment; with an impressive average of 16.8mpg.

 

[peterk9]

Still running 91 octane at $1.07/L ($4.00/gal) and enjoying every moment; with an impressive average of 16.8mpg.

According to 'Fuelly', I'm averaging 17.1 mpg (US) or 20.6 mpg in Canadian terms.

 

[Ruz]

Hello all. New to the forum, just purchased a 2017 Sport and curious what octane others are using. I know the manual says 87 is ok, but then it also states that best performance comes from 91.

Thoughts from people that have tried both, especially those with the 3.5 EcoBoost engines?

Thanks!

 

[613GT500]

Strictly 91 and only at top tier stations, such as Costco.
This is a performance engine with force induction and shouldn't be filled with anything less.

 

[ExPlat]

+ 1 to 91 octane....
I like the way the car performs with 91 octane.

 

[peterk9]

Hello all. New to the forum, just purchased a 2017 Sport and curious what octane others are using. I know the manual says 87 is ok, but then it also states that best performance comes from 91.

Thoughts from people that have tried both, especially those with the 3.5 EcoBoost engines?

Thanks!

Welcome to the Forum.
Your thread has been merged with this one found with the 'Search' feature. There's not much that hasn't been discussed.
As the Manual states, it runs fine on 87. That's all I've used in my 2014 MKT Ecoboost and my 2017 Platinum. If you want to achieve the advertised HP and torque numbers for top performance then use 93 octane. That is what was used to achieve those numbers. To my way of thinking and for my driving style, that would be a complete waste of money. But like asking about oil and oil changes, this octane one will get you replies that are all over the place. I seem to get the same mileage or better than some using regular.

Peter

 

[ExPlat]

In dear ol' California the highest octane fuel available at most pumps is 91 octane.

 

[Phil DeVtec]

I think I'll run 87 for the first 1000 miles, then 91 for the next 1000, and then 93 for the next 1000. I'll keep a log of MPG for each and see which is best. Not that it really matters, since I have the X5d as a daily, but it would be cool to see.

 

[peterk9]

I think I'll run 87 for the first 1000 miles, then 91 for the next 1000, and then 93 for the next 1000. I'll keep a log of MPG for each and see which is best. Not that it really matters, since I have the X5d as a daily, but it would be cool to see.

I think you'll find that any slight improvement in gas mileage will not be offset by the extra cost of the gasoline.

Peter