What a difference 91 octane makes in the 2.0 motor.

[Mark S.]

It also helps in cooling the intake charge.

Can you explain the physics on this?

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[sajohnson]

It's for efficiency. Higher compression ratio yields better fuel economy.

I wonder why there is a difference in the compression ratio between the 2.0L and the 1.5L engines?

I'd think Ford would have found that one or the other is optimal and they would both be the same.

 

[SgtT11B]

Can you explain the physics on this?

Ethanol just runs cooler than regular gasoline, that's all I can tell you I am no fuel engineer.

Here is what I found.

Ethanol burns cooler than regular gasoline. It requires lower combustion temperatures. Also, it creates a thermodynamic cooling effect that regular gasoline doesn’t offer. This is quite beneficial because E85 helps keep the engine cool. This helps keep the engine healthy.

There was a test a while back they did a test on a race engine that was making 700 horsepower. They used a straight E85 tune with E85 fuel versus a regular race gas tune using ms109 VP racing which is also 105 octane as the E85. Even though it had the same octane rating it made 30 to 40 more horsepower than the racing fuel.

 

[Xrayphoton1]

I have a hard time believing that a simple little catch can would not be implemented by Ford if there were any merits to it. It would certainly be cheaper than spending millions of dollars on warranty and extended warranty repair bills, assuming of course that there is a significant failure rate to begin with.

The problem with having a factory catch can is who is going to regularly empty it before it's full? Most owners would forget it's even there

 

[Mark S.]

Ethanol burns cooler than regular gasoline. It requires lower combustion temperatures.

This is partially correct. Ethanol does indeed burn at a lower temperature than gasoline--roughly 125F--during combustion. I'm guessing you meant to say that ethanol requires a higher ignition temp, not combustion temp, but that's not correct. Ethanol is much higher octane (110+) than gasoline, so it requires a higher ignition temperature. This is one of the many benefits of using ethanol in race engines, which generate tremendous amounts of heat.

Also, it creates a thermodynamic cooling effect that regular gasoline doesn’t offer. This is quite beneficial because E85 helps keep the engine cool. This helps keep the engine healthy.

Your original comment was about 10% ethanol blends, not E85. You can't burn E85 in these engines without significant modifications. Even though ethanol burns slightly cooler than gasoline, blending ethanol with gasoline can actually result in HIGHER combustion temps. This is because a) ethanol burns best at a significantly different fuel/air ratio than gasoline, and b) ethanol releases oxygen as it burns. The result of these two factors can be a too-lean mixture, which increases combustion temps.

That said, Ford's designers set up its EcoBoost line of engines to operate with 10% ethanol blends because that's what's sold at pumps pretty much nationwide. It programmed the PCM (powertrain control module) to adjust the fuel/air ratio on the fly to accommodate different fuels, which means operating temperature will not be affected by ethanol blends.

There was a test a while back they did a test on a race engine that was making 700 horsepower. They used a straight E85 tune with E85 fuel versus a regular race gas tune using ms109 VP racing which is also 105 octane as the E85. Even though it had the same octane rating it made 30 to 40 more horsepower than the racing fuel.

There's no question that ethanol offers many benefits over gasoline in high-horsepower race engines. But that's beyond the scope of this discussion. What we want to know is what how does the use of the permitted ethanol blends (up to 15% according to the Owner's Manual) affect operation of the engines in our cars. The answer to that is the PCM adjusts operating parameters, including fuel/air ratio, to manage engine heat, so there's essentially no difference.

The video below from Midwest Bioenergy explains the chemistry if you're interested.

 

[Meanderthal]

Can you explain the physics on this?

When Mark said that, I was just waiting for this:

This is partially correct. Ethanol does indeed burn at a lower temperature than gasoline--roughly 125F--during combustion. I'm guessing you meant to say that ethanol requires a higher ignition temp, not combustion temp, but that's not correct. Ethanol is much higher octane (110+) than gasoline, so it requires a higher ignition temperature. This is one of the many benefits of using ethanol in race engines, which generate tremendous amounts of heat.



Your original comment was about 10% ethanol blends, not E85. You can't burn E85 in these engines without significant modifications. Even though ethanol burns slightly cooler than gasoline, blending ethanol with gasoline can actually result in HIGHER combustion temps. This is because a) ethanol burns best at a significantly different fuel/air ratio than gasoline, and b) ethanol releases oxygen as it burns. The result of these two factors can be a too-lean mixture, which increases combustion temps.

That said, Ford's designers set up its EcoBoost line of engines to operate with 10% ethanol blends because that's what's sold at pumps pretty much nationwide. It programmed the PCM (powertrain control module) to adjust the fuel/air ratio on the fly to accommodate different fuels, which means operating temperature will not be affected by ethanol blends.



There's no question that ethanol offers many benefits over gasoline in high-horsepower race engines. But that's beyond the scope of this discussion. What we want to know is what how does the use of the permitted ethanol blends (up to 15% according to the Owner's Manual) affect operation of the engines in our cars. The answer to that is the PCM adjusts operating parameters, including fuel/air ratio, to manage engine heat, so there's essentially no difference.

The video below from Midwest Bioenergy explains the chemistry if you're interested.

Excellent information as always Mark!

 

[PaulOinMA]

Recent article on regular versus premium.

Is Premium Gas Worth It? We Test High Octane on 4 Popular Vehicles (caranddriver.com)

Numbers I saw for the previous single scroll 2.0T was 240 h.p. on premium, 233 on regular.

 

[SgtT11B]

Tell me about it. I had a 2.0 escape that felt like a rocket compared to this badlands Bronco. I usually switch between super and regular but I’ll switch to straight high test from now on. Did you notice the turbo lag in certain spots of the power band is much more pronounced in the Bronco vs. the Escape ? I certainly have.

Sorry didn't see this until now. In sport mode I haven't noticed much of if any difference. I never drive this vehicle nor the Escape in normal mode. The throttle mapping is just to lethargic.

 

[SgtT11B]

Recent article on regular versus premium.

Is Premium Gas Worth It? We Test High Octane on 4 Popular Vehicles (caranddriver.com)

Numbers I saw for the previous single scroll 2.0T was 240 h.p. on premium, 233 on regular.

The numbers I used were based on the Mustang with the 2.3L.

 

[sajohnson]

This is partially correct. Ethanol does indeed burn at a lower temperature than gasoline--roughly 125F--during combustion. I'm guessing you meant to say that ethanol requires a higher ignition temp, not combustion temp, but that's not correct. Ethanol is much higher octane (110+) than gasoline, so it requires a higher ignition temperature. This is one of the many benefits of using ethanol in race engines, which generate tremendous amounts of heat.



Your original comment was about 10% ethanol blends, not E85. You can't burn E85 in these engines without significant modifications. Even though ethanol burns slightly cooler than gasoline, blending ethanol with gasoline can actually result in HIGHER combustion temps. This is because a) ethanol burns best at a significantly different fuel/air ratio than gasoline, and b) ethanol releases oxygen as it burns. The result of these two factors can be a too-lean mixture, which increases combustion temps.

That said, Ford's designers set up its EcoBoost line of engines to operate with 10% ethanol blends because that's what's sold at pumps pretty much nationwide. It programmed the PCM (powertrain control module) to adjust the fuel/air ratio on the fly to accommodate different fuels, which means operating temperature will not be affected by ethanol blends.



There's no question that ethanol offers many benefits over gasoline in high-horsepower race engines. But that's beyond the scope of this discussion. What we want to know is what how does the use of the permitted ethanol blends (up to 15% according to the Owner's Manual) affect operation of the engines in our cars. The answer to that is the PCM adjusts operating parameters, including fuel/air ratio, to manage engine heat, so there's essentially no difference.

The video below from Midwest Bioenergy explains the chemistry if you're interested.

Good video, thanks.

 

[13MikeH]

With gas prices returning to just above double what they were about two years ago I tried some 91 on the way to DTW and man...I have to say, I didn't notice a bit of difference except for spending way more on gas than I should have to.

 

[sajohnson]

Recent article on regular versus premium.

Is Premium Gas Worth It? We Test High Octane on 4 Popular Vehicles (caranddriver.com)

Numbers I saw for the previous single scroll 2.0T was 240 h.p. on premium, 233 on regular.

I just read the article. C&D got some interesting results. Here's the summary:

The difference 93 octane makes in the F-150 is substantial. The times improve more than a 20 hp difference would suggest. 0>100 dropped from 16.0 seconds to 14.2?! That's huge.

Oddly, the Charger saw greater increases in hp and torque yet its times stayed essentially the same.

 

[13MikeH]

I just read the article. C&D got some interesting results. Here's the summary:

The difference 93 octane makes in the F-150 is substantial. The times improve more than a 20 hp difference would suggest. 0>100 dropped from 16.0 seconds to 14.2?! That's huge.

Oddly, the Charger saw greater increases in hp and torque yet its times stayed essentially the same.

By nature I call foul. No other vehicle on that list showed that much impact 0-100. And better still even the data specific to the F-150 for 0-60 is half a second like most of the other vehicles. I call outlier data point that does not fit with the other trends. Something is wrong.

 

[PaulOinMA]

Don't know if I posted the following in here or a similar thread.

There used to be Ford reps on fordescape.org several years ago. We had this discussion. They spoke to a Ford engineer. Said that the incremental h.p. increase with premium may be felt at WOT or when towing. Other than that, save money and buy regular.

Edit. I believe the discussion was of the 3G 2.0T. 240 published h.p. vs. roughly 233 on regular.

Those numbers look similar to what C&D observed. Premium won't be noticed on my 4-mile drive to the supermarket.

 

[sajohnson]

Don't know if I posted the following in here or a similar thread.

There used to be Ford reps on fordescape.org several years ago. We had this discussion. They spoke to a Ford engineer. Said that the incremental h.p. increase with premium may be felt at WOT or when towing. Other than that, save money and buy regular.

Edit. I believe the discussion was of the 3G 2.0T. 240 published h.p. vs. roughly 233 on regular.

Those numbers look similar to what C&D observed. Premium won't be noticed on my 4-mile drive to the supermarket.

I agree that premium won't be noticed driving 4 miles to the supermarket.

I've posted that we use premium because we drive so little that the additional cost is minimal, and I'm a lead foot 'car guy' so I like the idea of having the maximum performance available (even if it's not a huge difference).

Most people probably run regular, save some money, and go on down the road.

That said, what C&D found was a 20 hp increase with the F-150. Granted, that's a larger, more powerful engine, so we can expect the difference with the BS BL 2.0L turbo to be less, but the bigger factor is the decrease in the truck's times. 0>60; 0>100; and 1/4 mile (time and speed) all improved significantly with 93 octane.

Of course, just because it's also a turbocharged Ford does not necessarily mean we can expect similar improvements with the BS BL.

Then again, see Mark's post #61. Mustang testing showed a bit over 10% difference -- or about 25 hp with a 2.0L Badlands -- a drop from 250 to 225 hp.

One take-away from the C&D testing seems to be that there are large differences between vehicles. Some were slightly faster and/or made more hp and torque with 87 octane. There is no consistency.

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