What a difference 91 octane makes in the 2.0 motor.

[thekingprawn]

We need the mythbusters to do weighted fuel tests again.

Is there any benefit to stepping up to mid grade gas? I have 87, 89, and 91 octane to choose from, and jumping all the way to $0.40 more per gallon is a big ask. Half that I'm more amenable to. Although, coming from the 130hp Nissan to the 250hp BSBL is a very significant difference in performance already.

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[Mark S.]

We need the mythbusters to do weighted fuel tests again.

Is there any benefit to stepping up to mid grade gas? I have 87, 89, and 91 octane to choose from, and jumping all the way to $0.40 more per gallon is a big ask. Half that I'm more amenable to. Although, coming from the 130hp Nissan to the 250hp BSBL is a very significant difference in performance already.

Dyno testing by owners in the Mustang EcoBoost community suggested a 10% hit on power when using regular over premium for the 2.3L EcoBoost. If that holds true for the 2.0L, you're only getting some 225 hp with regular in your Badlands. If the power increase is linear with an increase in octane (and we have no reason to believe otherwise), you can expect an approximate 12 hp boost switching to a midgrade fuel.

 

[69cuda340s]

Someone in one of the tuning threads on this forum did a baseline 0-60 run with his badlands a while back. He clocked 5.9 seconds. I asked if he let it cool down to get that number he said no just drove to deserted road and did the run. Dont recall if he ran premium fuel or not.

These vehicles are mass produced with a lot of tolerances on a lot of parts both mechanical and electrical. And different altitudes, diff climates, and diff fuel blends around the country. A lot of variables. Not to mention subjective opinions on the performance of the vehicle.

So some will believe it runs better on premium. Some say they don't see any difference. Mine seems to run a lot stronger and smoother with 93 octane so that what I run. But if someone else is happy with 87 great then keep using it save your money.

 

[13MikeH]

There are two major flaws with this video. First, the MPG test is using the indicated value as the standard. That indication is affected by a great number of factors, and unless they are all the same for both tests the result is meaningless. The only way to properly test is to average over several tanks. I did this with my car (results here and here), and measured no significant difference between octanes for fuel economy.

Second, the PCM (powertrain control module) takes time to adjust to a change in fuel octane. If you've been burning regular gas exclusively the fuel/ignition mapping is set such that the engine will produce less power to mitigate knocking. After putting premium in the tank the knock sensor will fire off less often—because engine power is down and higher octane requires more heat/pressure to ignite—and the PCM will begin to advance timing to permit greater power output. Eventually the knock sensor will begin to fire again, the PCM will stop advancing timing, and the engine is now producing the maximum possible power with the new octane fuel. This takes time. How long? I don't know for sure, but we can garner clues from vendors who sell "tunes." Many include documentation suggesting up to 100 miles of driving before the PCM fully adjusts to changing parameters.

Simply arguing with you? many are viewing this as peak repeatable performance upgrade. To me that's the beauty of the video. Just a dude, in his Bronco, fills up gas, gets his mpg and clocks 0-60/0-80. He then repeats with 93 octane...bottom line every drive you take has nuances. Traffic, distance, pedal pressure. Nobody drives in a dyno lab?

 

[sajohnson]

We need the mythbusters to do weighted fuel tests again.

Is there any benefit to stepping up to mid grade gas? I have 87, 89, and 91 octane to choose from, and jumping all the way to $0.40 more per gallon is a big ask. Half that I'm more amenable to. Although, coming from the 130hp Nissan to the 250hp BSBL is a very significant difference in performance already.

I've been working on cars since the 1970s. Back in the day of course, the answer to your question was no. Unless an engine had (say) carbon deposits that would get red-hot and cause preignition, there was no benefit to using higher octane than specified by the mfr. The engine had no way of knowing it was burning higher octane fuel, and could not take advantage of it anyway.

Flash forward -- most modern engines can vary valve timing, ignition timing, and boost pressure (if turbo/supercharged). They have knock sensors to tell the ECU when to retard the timing and/or reduce the boost. So they definitely *can* and do benefit from higher octane.

The subjective question is, is it worth it?

By definition, all octane levels of "Top Tier" fuels (most major brands) must have the same higher level of detergents and other additives. So there is zero benefit there.

As for performance, I haven't done a deep dive into the subject, but my sense is that higher octane does not make a huge difference. See the video I posted above (just something I grabbed off Google) and my sad tale about 93 octane only giving my Cobb Stage 2 modified WRX 5-10 additional hp (according to Cobb Engineering). That's like turning the A/C off.

All that said, all vehicles are different. Some are optimized for at least 91 octane. They will run on lower octane gas but will not be happy. Others are designed with the assumption that 87 will typically be used. The turbo size may be selected based on that assumption -- meaning max boost can be lower, and therefore (usually) the turbo can be smaller (less mass) so there is less turbo lag. That's all good, but it means there is little if any excess boost capacity to tap into at higher rpm with 91-93 octane fuel.

12/30/23: Edit to clarify that I'm referring to 'tuning' a turbocharged engine, where in some cases there may be extra boost available, and the engine can handle it.

With our Bronco Sports, my guess is it won't make much difference -- except perhaps when under extended heavy load, like when towing in the mountains.

Personally -- speaking only for myself, not making any recommendation -- we will likely continue using 93 octane for whatever small increase in performance and drivability it gives because we drive very little. The extra $0.60/gallon is only (say) $60 more per year. For others it might be an additional $600/year, which is significant.

 

[thekingprawn]

Just for poop and guffaws today I drove to work in sport mode. Other than the jerk who decided we were all getting on the highway at 45 mph I really, really liked the way it drove in sport mode. The acceleration felt smoother, the shift points where were they intuitively should be, and the heavier steering feel was a significant improvement over normal mode. I'll watch the gauge and see if the MPG starts dropping, but for the subjective reasons listed I may try driving in sport mode most of the time.

 

[sajohnson]

There are two major flaws with this video. First, the MPG test is using the indicated value as the standard. That indication is affected by a great number of factors, and unless they are all the same for both tests the result is meaningless. The only way to properly test is to average over several tanks. I did this with my car (results here and here), and measured no significant difference between octanes for fuel economy.

Second, the PCM (powertrain control module) takes time to adjust to a change in fuel octane. If you've been burning regular gas exclusively the fuel/ignition mapping is set such that the engine will produce less power to mitigate knocking. After putting premium in the tank the knock sensor will fire off less often—because engine power is down and higher octane requires more heat/pressure to ignite—and the PCM will begin to advance timing to permit greater power output. Eventually the knock sensor will begin to fire again, the PCM will stop advancing timing, and the engine is now producing the maximum possible power with the new octane fuel. This takes time. How long? I don't know for sure, but we can garner clues from vendors who sell "tunes." Many include documentation suggesting up to 100 miles of driving before the PCM fully adjusts to changing parameters.

Your results don't surprise me. I would not expect much difference in fuel economy between 87 and 91/93 octane.

I've never trusted CPU generated MPG. In part because we've never had a vehicle that had that feature (the 2002 WRX is the newest) -- so I have never had a chance to check accuracy. Of course I could be off-base, but a cynical person might suspect that the mfrs program the computer's MPG calculation to be "optimistic".

I've always used ye olde miles traveled divided by actual gallons used.

That said, maybe MPG displays in cars are pretty accurate. I've never had reason to look into it (until now).

FWIW, the guy did say he ran the same 30 mile loop each time.

I liked the 0>60 video you linked to (BTW, both links went to the same video). That guy does a good job. He basically described the C&D method I mentioned (knocking the first foot off the time).

I can confirm what he said about the WRX. Mine is modified to about the STi level. Even with the significantly reduced turbo lag (from Cobb exhaust), if you drive it normally -- start from a stop at just above idle, engage the clutch slowly, and then floor it, it's a dog. I used to jokingly say it was slower than a minivan, and that video confirms it. With most turbocharged engines you have to keep the rpm up above where the turbo kicks in or they fall on their face.

Also a good point about doing high rpm clutch dumps to get a low 0>60 time. That's hard on any car, but particularly one with AWD. With all 4 tires driven, significant tire spin is much less likely. Something has to give, and that's usually gears in the transmission. I've never done that to my WRX, not even once.

At least with the BS (or any AT vehicle) there are fewer ways to cheat (and abuse the car).

Good point about the PCM taking some amount of time to adjust to varying octane levels. He did run the 0>60/0>80 test after the 30 mile MPG loop, but perhaps that was not enough time. If it isn't, then maybe we can expect more of an increase using 91/93 in the BS.

FWIW, I do recall that Cobb had a method to force the PCM to 'learn' the new tune quickly. It's been years, but it involved loading the engine down by flooring the throttle and applying the brakes (ideally while climbing a hill). Of course the guy in the video did not do anything like that AFAIK.

 

[sajohnson]

Just for poop and guffaws today I drove to work in sport mode. Other than the jerk who decided we were all getting on the highway at 45 mph I really, really liked the way it drove in sport mode. The acceleration felt smoother, the shift points where were they intuitively should be, and the heavier steering feel was a significant improvement over normal mode. I'll watch the gauge and see if the MPG starts dropping, but for the subjective reasons listed I may try driving in sport mode most of the time.

Of course one factor in the MPG will be if sport mode encourages a heavier foot.

 

[thekingprawn]

Of course one factor in the MPG will be if sport mode encourages a heavier foot.

I'm generally a lighter foot person anyway. The first week or so the BS seemed like too much for me even if I kept the RPMs below 3K. Now I'll let it shift right around 3k (or maybe a touch higher) and it's fine. I did pass someone with frustration one day causing my wife to say "what the hell was that?!?" after I accelerated in the passing lane and the thing seemed almost to get squirrely.

 

[sajohnson]

I'm generally a lighter foot person anyway. The first week or so the BS seemed like too much for me even if I kept the RPMs below 3K. Now I'll let it shift right around 3k (or maybe a touch higher) and it's fine. I did pass someone with frustration one day causing my wife to say "what the hell was that?!?" after I accelerated in the passing lane and the thing seemed almost to get squirrely.

"Squirrely" is not an adjective I like to hear. Any chance it was the pavement?

Perhaps tire pressure is significantly higher than Ford's 33/33 psi spec?

'Passing vehicles with frustration' used to be an almost daily occurrence for me, back when I was commuting 75-100+ miles every day in the WRX. That's in part because I had a 'reverse commute' (PM shift) so it was not bumper-to-bumper traffic. I-70 and 270 were typically open, but the "keep right except to pass" concept has yet to sink in around here, and there were frequently drivers who would camp out in the left lane next to a truck doing 55 mph.

Anyway, I just read your post to my wife -- the Badlands is really her vehicle -- and suggested she try sport mode.

 

[thekingprawn]

"Squirrely" is not an adjective I like to hear. Any chance it was the pavement?

Perhaps tire pressure is significantly higher than Ford's 33/33 psi spec?

'Passing vehicles with frustration' used to be an almost daily occurrence for me, back when I was commuting 75-100+ miles every day in the WRX. That's in part because I had a 'reverse commute' (PM shift) so it was not bumper-to-bumper traffic. I-70 and 270 were typically open, but the "keep right except to pass" concept has yet to sink in around here, and there were frequently drivers who would camp out in the left lane next to a truck doing 55 mph.

Anyway, I just read your post to my wife -- the Badlands is really her vehicle -- and suggested she try sport mode.

It felt like the back end might have broken loose just a tiny bit when the power was sent aft. I'm sure a combination of road debris, warmth brining up oil, and giving it the beans while changing lanes contributed to things happening. Pressure is reading all around 33-35 (R front is 1 psi higher than the others), and the fancy air the dealership sold me keeps the pressure within 3 regardless of temperature.

Definitely give sport mode a try. I plan on using it all week as a test. The BS runs damn fine in normal, but sport just had an added feel of confidence, if that's the right descriptor. As fuel prices come down the amount of MPGs I'm willing to give to the cause is increasing. I never found a decrease from using it in my Nissan, but it also made little enough difference in the experience to bother most of the time.

 

[Escape2Bronco]

Someone in one of the tuning threads on this forum did a baseline 0-60 run with his badlands a while back. He clocked 5.9 seconds. I asked if he let it cool down to get that number he said no just drove to deserted road and did the run. Dont recall if he ran premium fuel or not.

These vehicles are mass produced with a lot of tolerances on a lot of parts both mechanical and electrical. And different altitudes, diff climates, and diff fuel blends around the country. A lot of variables. Not to mention subjective opinions on the performance of the vehicle.

So some will believe it runs better on premium. Some say they don't see any difference. Mine seems to run a lot stronger and smoother with 93 octane so that what I run. But if someone else is happy with 87 great then keep using it save your money.

Today’s cars account for the difference. It’s not like back in the day where you’d knock a hole in your piston running low octane fuel on a high compression motor with the timing set for oomph. I’m guessing you know this for sure.

 

[Mark S.]

It felt like the back end might have broken loose just a tiny bit when the power was sent aft. I'm sure a combination of road debris, warmth brining up oil, and giving it the beans while changing lanes contributed to things happening.

Relative to other SUVs on the market, the Badlands has a short wheel base with a lot power. It also sits on higher, softer springs. The taller springs change suspension geometry, specifically the scrub radius. All of these factors contribute to torque steer, which is what I suspect you were feeling.

The next time you're out and about try giving it the beans while gently steering left and right. You might notice the steering wheel tries to move on its own. That's torque steer.

 

[Mark S.]

That said, maybe MPG displays in cars are pretty accurate. I've never had reason to look into it (until now).

I compared displayed vs measured for my testing. Displayed is consistently higher than actual.

FWIW, the guy did say he ran the same 30 mile loop each time.

True, but the route is only one of many factors that affect displayed mileage. In my testing the difference between displayed and actual varied from around +1 to +2.5.

He did run the 0>60/0>80 test after the 30 mile MPG loop, but perhaps that was not enough time.

That's the point; we don't know.

FWIW, I do recall that Cobb had a method to force the PCM to 'learn' the new tune quickly. It's been years, but it involved loading the engine down by flooring the throttle and applying the brakes (ideally while climbing a hill).

Some "tune" vendors suggest 4-5 moderate (~75% throttle) acceleration runs between 2500 - 5000 RPM in a middle gear. You'd have to put it in manual mode to get the tranny to hold a gear. Ford's maintenance documentation includes instructions on how to put the PCM through a complete "drive cycle," after which all the stored data will have been updated. Based on that, I don't think 30 miles of cruising around at highway speeds would do it.

 

[sajohnson]

I compared displayed vs measured for my testing. Displayed is consistently higher than actual.


True, but the route is only one of many factors that affect displayed mileage. In my testing the difference between displayed and actual varied from around +1 to +2.5.

Good to know. As I said above:

"I've never trusted CPU generated MPG. In part because we've never had a vehicle that had that feature (the 2002 WRX is the newest) -- so I have never had a chance to check accuracy. Of course I could be off-base, but a cynical person might suspect that the mfrs program the computer's MPG calculation to be "optimistic".

I've always used ye olde miles traveled divided by actual gallons used."

So your experience confirms my suspicion -- at least for the vehicles you've tested (and probably others as well).

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