87 vs 89 vs 93 octane - my findings

[Jeremygsu]

I have a long commute for my job (75 miles each way) and purchased a '15 Expedition XLT back in March with 49k on the clock. I sold my '16 Tundra 4x4 and was curious on what the Expedition would get with the various octanes as I had heard the turbo'd engine was more affected by the octane ratings than a normal gas engine.

I decided to keep a log and run 5 tanks of each octane to see if there was a difference. The daily route is from Ocala, FL to Orlando and back. I tried to keep the speeds consistent using cruise control as much as possible and minimizing idle time. I typically ran 72mph down and 80mph back. I also reset the computer at each fill up and compared that to hand calculations.

Here were my findings:

87 octane -
Calculated vs computer
17.20 vs 18.1
17.10 vs 18.1
17.30 vs 18.5
16.20 vs 17.3
17.50 vs 18.9

87 Avg 17.06 vs 18.2

89 octane
17.10 vs 18.3
16.89 vs 18.2
17.77 vs 18.7
17.45 vs 18.7
16.85 vs 18.1

89 Avg 17.21 vs 18.4

93 octane
18.56 vs 19.8
18.36 vs 19.6
19.58 vs 20.8
18.00 vs 19.0
17.34 vs 18.2

93 Avg 18.36 I forgot to record the computer recording for the last fill-up.

So 93 octane does yield better mileage but will cost you more money.

It also showed that the computer is not accurate compared to Fuelly or hand calculations.

I am going to try 5 tanks of 91 next to see what that yields.

This was just for my personal findings and nothing else.

Jeremy

 

[210M]

This is good stuff... Thanks for putting in the time and effort. Did you notice any significant difference in engine performance?

 

[Boostedbus]

Is your Expedition 4x4 and regular wheel base? Also what axle ratio do you have? I also assume you are running air conditioning and not windows down in FL.

 

[Jeremygsu]

This is good stuff... Thanks for putting in the time and effort. Did you notice any significant difference in engine performance?

Honestly, I didn't get on it that much during these trials to really get a good feel of the power difference. I think it had more umph and ran smoother, but to be honest before I started this I didn't think the power was bad running 87. Coming from my 5.7 Tundra I thought the mid-range power was great once you got past the turbo lag.

 

[Jeremygsu]

Is your Expedition 4x4 and regular wheel base? Also what axle ratio do you have? I also assume you are running air conditioning and not windows down in FL.

Sorry. Mine is a regular wheelbase 4x2 and I am unsure of the rear axle ratio. My commute is about 69 miles highway and 6 miles side road. Yes, I ran the A/C the whole time, sometimes blasting it the whole way.

Another note, I was actually able to keep my cruise control on more during the initial 87 testing because of Covid there was nobody on the freeway. During the 93 tests I had to take it off more frequently because of traffic. The tests may have yielded even better results if I could have done it in April as well when we were shutdown.

 

[mquick5]

My 2017 xl 4x4 averages 13.7 but on the freeway sometimes the dash thingy will show well above 20mpg on 87 octane.

Sent from my SM-G930T using Tapatalk

 

[JasonH]

This is good stuff... Thanks for putting in the time and effort. Did you notice any significant difference in engine performance?

There is a readily discernible difference between 87 and 93 octane. I tow on 93 only, but even without a heavy load I can feel the difference. The engine pulls timing on 87 because the difference is noticeable even at part throttle, where peak boost wouldn't come into play.

 

[07navi]

So what's the bottom line? More power? Better mpgs? Worth the extra money? Only good for towing? Good for all years? Waste of money?

 

[Aspen03]

So what's the bottom line? More power? Better mpgs? Worth the extra money? Only good for towing? Good for all years? Waste of money?

Based on the data just cruising down the hwy on 93 looks to be a loss, financially speaking. A 10% mpg gain w a fuel that's 20% more costly in most areas. Around here it can approach 30% with gas prices where they currently are. Of course the data isnt really useful for all years. The 15 is a completely different everything from likely 70% of the expeditions on the road today.


OP: I've seen similar results in my 2003. I run through a tank every 8 or 9 days and while on a commute what so else do I have to do other than track mileage. 93 routinely nets me about a 1-1.5mpg increase...why I dont know because I'm cruising at 67-68 and rarely if ever sit in traffic and engine load is low. Just stop light here and there. On a 5.4 that's about a 10% difference as well. Gas from same station, same pump and I generally run it down to about 40mi range beforehand which results in about a 26g fill. If I'm loaded up w the whole gang and packed full 93 does tend to run better in my experience.

I'm kind if shocked you dont get better being a 4x2. I'm in a 4x4 EB with 221k on it and average out just shy of 16 most of the time. Of my 24mi commute each way there is 17mi hwy so I actually have more in town than you do from a percentage of the drive than you but I would say the difference in traffic is probably what gets you. My last tank I averaged 14.86 but I was also relegated to drive through for lunch and ate in the car a couple times w AC going. That was easily an hour of idle time amongst the days.

 

[Boostedbus]

I'm kind if shocked you dont get better being a 4x2.

He said he’s running 80 mph on the trip home. I know my mileage suffers when I crank up to 80 - 85 mph. I’ve got 3.73 gears though. Lower gear ratios come into play more at high speeds especially on flat ground in Florida. He probably doesn’t have 3.73’s with the 2wd and doesn’t need them on flat ground unless he’s towing a parachute. I’m sure he could do better if he wanted to , but I think his goal was to be consistent in all tests with his driving style. There is no way I could be that consistent even with one tank. I’d be too impatient and have to WOT around someone if they were just creeping along.

 

[Jeremygsu]

He said he’s running 80 mph on the trip home. I know my mileage suffers when I crank up to 80 - 85 mph. I’ve got 3.73 gears though. Lower gear ratios come into play more at high speeds especially on flat ground in Florida. He probably doesn’t have 3.73’s with the 2wd and doesn’t need them on flat ground unless he’s towing a parachute. I’m sure he could do better if he wanted to , but I think his goal was to be consistent in all tests with his driving style. There is no way I could be that consistent even with one tank. I’d be too impatient and have to WOT around someone if they were just creeping along.

Running 80 definitely drops the mileage on the computer quickly. I tried to be consistent but I'm not saying I didn't floor it here or there. It's extremely difficult to be 100% consistent over 15 tanks of gas and that many thousands of miles. I had some variances even with the same octane as everyone can see. I don't believe I have the 3.73 gears. I'll have to call the dealer to find out what it was built with.

I do think the 93 offers better performance and fuel economy, but it's going to cost you more money to run it. Is it worth it? Well, that's up to you. If I can afford it I like the idea of better mileage and it running better, even if it is a waste of money.

One thing I confirmed with yet another vehicle is the computers can be off by 1-1.5 mpg's. My '06 F-150 was like that too. I will say that the computer seemed to be consistent with it being off where my Tundra could be all over the place.

I am curious to see if 91 offers similar results as 93 so I'll be trying that next.

 

[Aspen03]

I didnt even see the 80mph part. Makes sense, I have 3.73's w the hd tow and lsd and anything over low 70s wrecks fuel economy. 72-73 is about as fast I cruise for hwy. Being its 55 the entire trip that's probably fast enough anyway. When you have the aerodynamics of a single wide trailer resistance comes up rather quickly.

I used to be the same way in ither vehicles. On any given day it wouldnt be uncommon to close in on triple digits. Wasnt hard w the old car, wot going around a semi you could 65-100 by the time you safely cleared the truck.

 

[Brent Wahl]

Here is a list of the results:

• 87 octane 0 to 60 run: 5.9-seconds
• 93 octane 0 to 60 run: 5.3-seconds
• 87 octane quarter-mile time: 14.5 seconds
• 93 octane quarter-mile time: 14 seconds
• Speed trap findings: 4 mph difference
• 87 octane shows 1.9 psi dip in turbo response

So what do the findings mean? You don't have to be an engineer to see that 93 octane gasoline outperforms 87 gasoline. To show this more clearly C&D performed a real-world test that proved premium gasoline performs better. They took the vehicles used for testing to an interstate where they set the cruise control to 75 mph. Cruising at 75, the testers found that premium (93 octane) gasoline returned 17.6 mpg. When they changed the fuel to regular (87 octane), they found that the Ford F150 with the EcoBoost powerplant achieved 17 mpg, a difference of .6 mpg.

Ford F150 Owner Will Pay More For Performance

So what does this all mean? It means that if you opt for premium fuel, you will be spending more at the pump because the higher-quality gasoline is much more expensive than 87-octane regular. Think of it this way, though you may be spending more at the pump, you are gaining better performance from the higher octane gasoline.

Follow Marc Stern, the Ford F150 Reporter for Torque News with news and tips about Ford trucks at @iraradioguy or on Facebook at mstern001.

Source: Car & Driver

https://www.torquenews.com/3769/ford-f150-performance-reflects-octane-level-93-definitely-better

 

[JasonH]

So what's the bottom line? More power? Better mpgs? Worth the extra money? Only good for towing? Good for all years? Waste of money?

The 93 octane provides better performance and mpg, but the mpg improvement will not offset the additional cost. I tow on 93 and daily drive on 87. I'm not romping on the accelerator often enough to enjoy the benefits of 93 while tooling around town. But when I'm merging onto the freeway with 18 wheelers, I want all the power the engine can deliver. The engine can be tuned to provide higher power levels on 87 if you don't care about your warranty.

 

[Trainmaster]

Anyone see similar effects on a 5.4?

Unless the motor adjusts the timing as the Ecoboost apparently does, premium gas would usually reduce your mileage as it has more additives and less BTU. If the timing advances automatically until detonation starts, then the mileage would be better, as premium is less volatile to pre-ignition.

Don't know how a 5.4 would handle this. I do know that this ethanol blend severely degrades mileage.

 

[LokiWolf]

I do know that this ethanol blend severely degrades mileage.

Haha! You know this from actually testing or by reading the evils of Ethanol on the Internet?

Most NA vehicles see less than 1-2% degrade in MPG on E10 vs E0 octane being the same.

Turbo vehicles may see the same MPG loss but gain power. Can’t find the post, but one of the respected tuning company’s in Canada where they removed E from the 94 Octane fuel but left it in the 87. The 87 with E made more power than the 94 without. Ethanol has timing advantages over straight gas that is VERY beneficial to Turbo motors.

93 all the way. I like the power, the MPG is slightly better. I would like to RUN E50 in the Expy, but too much a pain for the wife to mix.

Good Data from the OP above! I did similar testing when we first got our 17, a few years ago. I saw 93 to basically be a wash, so I saw a little bit more difference in MPG.

So 93, more power, better MPG, FAR less knock. Pay a little more. It is a 60K, Huge vehicle. Saving a few bucks isn’t why I bought it!




Sent from my iPhone using Tapatalk Pro

 

[chuck s]

93 octane is always 60¢/gallon more expensive than 87 here in Richmond. 87 can drop to $1.50 and 93 will be $210 (40% more expensive) or if like pre-COVID19 87 was $3.10 and 93 was at $3.70 (20% more expensive). I know the prices only because one of my other cars requires at least 91 and all we get here is 93. I run 87 in my '17 Expedition other than when towing my small travel trailer -- gives me a warm fuzzy feeling but it tows just fine on 87.

Ford notes the engine produces more power on 93. Frankly has adequate power for me on 87. The ECU handles timing to avoid knock as necessary.

I run ethanol-free gas in my lawn equipment. I think it's 89. It's also more expensive than Shell 93.

-- Chuck

 

[JExpedition07]

The 5.4 Triton (‘05+ 3-Valve engines only) definitely advance timing. Most 08+ 5.4L engines are Flex Fuel capable and on E-85 are rated +20 horsepower over the 87 octane rating. It also makes roughly 400 lb ft of torque on ethanol. Worth it to run E-85 all the time? Likely not with the mileage drop for a slight power increase. Worth it for towing or when you feel like romping on it? Probably. Depends on what year “Triton” engine though. The older pre 3-valve 5.4 motors weren’t adorned with the technology to advance timing to take advantage of higher octane of E-85, that came along with the 3-valve and the new ECM/knock/injection setup in ‘05.

 

[07navi]

People are going to run high octane all the time if it puts out more HP depending on how much they value the power and how much money they are willing to spend.

 

[LokiWolf]

93 octane is always 60¢/gallon more expensive than 87 here in Richmond. 87 can drop to $1.50 and 93 will be $210 (40% more expensive) or if like pre-COVID19 87 was $3.10 and 93 was at $3.70 (20% more expensive). I know the prices only because one of my other cars requires at least 91 and all we get here is 93. I run 87 in my '17 Expedition other than when towing my small travel trailer -- gives me a warm fuzzy feeling but it tows just fine on 87.

Ford notes the engine produces more power on 93. Frankly has adequate power for me on 87. The ECU handles timing to avoid knock as necessary.

I run ethanol-free gas in my lawn equipment. I think it's 89. It's also more expensive than Shell 93.

-- Chuck

You are going to the wrong stations. Even quality stations. My Kroger is only 30c/gallon between 87 and 93 currently. Max pre-COVID maybe 50c at the higher prices. FYI for you others that don’t know, I live on the other side of Richmond from Chuck.

For clarity these motors are tuned from the factory for 91ish. They detune based on detected knock, seen as KR(Knock Reduction) when logging.

The knock vs timing is how they determine learned Octane.

On 87 they regularly knock, but minimally. Even on 93 under heavy load they do, and pull timing. Safe, but it is important to know these motors detune, not tune up.

Lawn equipment is by far the best use of Non-ethanol. Because of open fuel systems and sitting, ethanol can be troublesome. The fact that it pulls moisture out of the air. My solution to that, EGO 56V Electric Mower, Blower, and Trimmer.



Sent from my iPhone using Tapatalk Pro