Testing premium fuel in the hybrid

[Ranko Kohime]

As I observed in this thread, the hybrid Maverick rarely runs the engine at Calculated Engine Load of higher than 70%, comparing to the 2017 Prius I owned which regularly ran at or above 95% load nearly any time the engine was above 1300 RPM.

Hypothesis: the larger engine, with the same compression ratio, (13.0:1) prefers a higher than 87 octane for best performance.

Expected results: higher load, and higher fuel economy. I do not expect it to be enough to warrant the continued purchase of premium fuel when not towing, and intend to return to 87, unless results are wildly better.

Stay tuned for results of this experiment.

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[HeyBales]

The stated compression ratio is not actually the same value since the Atkinson cycle causes less with intake valve open during part of compression distance.

You'll hardly be the 1st testing this as many threads have already had tests on it.

I got nothing out of a tank of premium.

Might search for those threads so even you don't have to stay tuned!

 

[AVC]

I don't recall any meaningful objective reporting on the differences; notably did the ICE timing map appear to be more aggressive with 91 vs 87, which would verify whether the 2.5L Atkinson recognizes and exploits higher octane.

All I saw was anecdotal posts regarding seat of the pants, or 0-60. WOT tests won't reveal the differences most notable from a timing advance improvement with higher octane for a typical "non-performance" tuned ICE; like improved throttle response and low to mid-range torque, and possibly some calculated torque or power output metrics.

 

[Chops]

I don't recall any meaningful objective reporting on the differences; notably did the ICE timing map appear to be more aggressive with 91 vs 87, which would verify whether the 2.5L Atkinson recognizes and exploits higher octane.

All I saw was anecdotal posts regarding seat of the pants, or 0-60. WOT tests won't reveal the differences most notable from a timing advance improvement with higher octane for a typical "non-performance" tuned ICE; like improved throttle response and low to mid-range torque, and possibly some calculated torque or power output metrics.

I have noted an improvement in MPG since switching from 89 to 91. Keeping track by hand in a notebook

I’m using 91 more for engine health than mpgs, however. Like a vaccination against the dreaded but rare knock disease. Trust the Science.

 

[h1k3rb]

I have noted an improvement in MPG since switching from 89 to 91. Keeping track by hand in a notebook

I’m using 91 more for engine health than mpgs, however. Like a vaccination against the dreaded but rare knock disease. Trust the Science.

Yes, it will make a difference in the EB but this thread is about the hybrid. From what I've read it's not going to help the hybrid at all.

 

[Cancunbadlands]

I’m using 91 more for engine health than mpgs, however. It's a turbo engine, 2.0l

 

[PeteBerner]

Your bio says you're in Texas, so your midgrade fuel is 89 octane which should be great if you want to run at a higher octane than just base/regular. 93 looks like the top octane for Texas and that seems like overkill for a hybrid. I'm in Colorado, where our octane levels are 85, 87, 91 because of the altitude, so I use 87 all the time in my hybrid (which is really like 89 octane at sea level). Consensus on the Internet (take that for what it's worth ) seems to be regular or midgrade for the hybrid and premium for the turbo ecoboost. The thing that a lot of people think is more important, is using top-tier gasoline versus whatever's cheap at a little corner mini-mart or grocery store. Name brands (Shell, Conoco, Philips 66, etc.) usually provide a better quality than some of the grocery store sludge tanks. I have noticed more of a difference going with a top-tier gas station than some of the watery junk that some other cheaper stations put out.

https://www.toptiergas.com/

 

[dochawk]

From what I've read it's not going to help the hybrid at all.

The only way that premium or mid grade is going to make a difference in the hybrid is if there's something more than an octane difference.

Once upon a time, that was the case; premium sometimes had different/better additives. But those days are long past. AFAIK, there are no longer any manufacturers that do this.

Also, the reason that octane matters on the ecoboost is that it adjusts timing and boost based upon available octane. I have never seen a report, here or anywhere else, that the hybrid does any such thing.

 

[Mavster Mechanic]

The hybrid does not advance timing with higher octane.

The only proven gas that gets higher MPG than E10 gas is gas without ethanol.

If you're already using ethanol free gas, you are getting maximum MPG for your conditions.

How you drive can vastly boost MPG.
I routinely get 55 MPG on E10!

This would probably be 60 MPG on neat gasoline.

 

[24hrsun]

The 2 things that I consider in gasoline is Top Tier and no ethanol. Around here I can get no ethanol at a select few stations but it is 91 octane. And if you want to make that no ethanol from a Top Tier certified fueling station that narrows the choices down further and in either case it will be 91 octane local to me. So when I can that is what I am buying.

The Maverick is too new and hasn't had that many tanks run through it yet, but typically it is the no ethanol that gives the MPG boost, but if you do the math economically you aren't likely to make up for the cost difference. My specific interest is in carbon deposits and keeping things clean over the long haul.

Lots of people are confused over the detergents used and the different certifications and what they mean. You can find a relatively recent video on The Motor Oil Geek youtube channel showing the testing info regarding the cleaners and fuel.

 

[Ranko Kohime]

The stated compression ratio is not actually the same value since the Atkinson cycle causes less with intake valve open during part of compression distance.

Might search for those threads so even you don't have to stay tuned!

I did forget to mention I was already aware of the Atkinson cycle, however the question is still raised, at least in my mind: does the effective compression still benefit from a higher octane?

I did search indeed, but with the Maverick having 2 powertrains, and the forum being what it is, I saw only topics where the EB and higher horsepower was the focus.

I don't recall any meaningful objective reporting on the differences; notably did the ICE timing map appear to be more aggressive with 91 vs 87, which would verify whether the 2.5L Atkinson recognizes and exploits higher octane.

All I saw was anecdotal posts regarding seat of the pants, or 0-60. WOT tests won't reveal the differences most notable from a timing advance improvement with higher octane for a typical "non-performance" tuned ICE; like improved throttle response and low to mid-range torque, and possibly some calculated torque or power output metrics.

This is definitely one area where I can hope to provide a meaningful report, whether the results are substantive or not. Calculated Load is a more reasonably objective measure than seat of the pants.

 

[Chops]

The 2 things that I consider in gasoline is Top Tier and no ethanol. Around here I can get no ethanol at a select few stations but it is 91 octane. And if you want to make that no ethanol from a Top Tier certified fueling station that narrows the choices down further and in either case it will be 91 octane local to me. So when I can that is what I am buying.

The Maverick is too new and hasn't had that many tanks run through it yet, but typically it is the no ethanol that gives the MPG boost, but if you do the math economically you aren't likely to make up for the cost difference. My specific interest is in carbon deposits and keeping things clean over the long haul.

Lots of people are confused over the detergents used and the different certifications and what they mean. You can find a relatively recent video on The Motor Oil Geek youtube channel showing the testing info regarding the cleaners and fuel.

Motor Oil Geek is the one stop channel for all oil related education needs. You seem pretty reliable too, thanks for info.

 

[HeyBales]

I did forget to mention I was already aware of the Atkinson cycle, however the question is still raised, at least in my mind: does the effective compression still benefit from a higher octane?

I did search indeed, but with the Maverick having 2 powertrains, and the forum being what it is, I saw only topics where the EB and higher horsepower was the focus.


This is definitely one area where I can hope to provide a meaningful report, whether the results are substantive or not. Calculated Load is a more reasonably objective measure than seat of the pants.

Yes there is confusion because folks on mobile devices cant see the profile info as to what engine.
And posters don't include in their post what engine.
So it gets sloppy - just as this thread has a bit.

But at the bottom of your thread now, and then at the bottom of those 2 threads - more.
Plenty of comments on tanks tested.

Considering the purpose of higher octane - no there's not going to be a benefit for slightly higher than 7.x:1 compression ratio. Perhaps some edge cases can be theorized.

 

[710-oil-614]

The 2.5L is mapped to 87 octane. Anything above 87 will provide zero additional benefits.

However, I wish you well in your research.

 

[dalola]

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