Regular vs Premium Gasoline

[BMCGC]

Those Aussie race trucks that launch off ramps on a road course are pretty cool. I saw one of those races a couple months back. It looked a lot more exciting than Nascar.

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[SilverPigeon]

They're lucky someone invented a thing called a "spring" ?
It's a shame these days that all circuit racing that looks like fun has no relation to "real" cars - you can't even buy the rally cars at a dealer ?

 

[Suns_PSD]

Does anyone know how to monitor timing advance/ retardation utilizing the Torque app?

Basically, I'm trying to see if the fuel I'm running (93 Octane with 15% E-85) provides enough Octane in this heat (about 105' most days) where I can maintain peak/ most advanced timing in this particular engine?

And then I'd like to drop Octane a bit once temps col off, probably just straight 93, if it allows me to maintain peak advance.

Thanks

 

[Calson]

The higher the compression ratio of a gas engine the more likely there is to be pre-ignition of the fuel when it is injected into the hot cylinders. The 35L engines have a compression ratio that is engineered for 87 octane rated gasoline. Ford recommends using 93 octane when towing to minimize pre-ignition when the engine is working harder to deal with the greater overall load and generating more heat (which is why for towing a larger capacity radiator is needed).

Commonly the Acura engine used by Honda will be virtually identical the engine they used in their Civic models except the Acura engine had a slightly higher compression ratio and so produced a little more horesepower. The gain was around 5 extra horsepower and it required the use of premium fuel in the Acura cars while the Civics could use regular gas.

It was the desire to boost octane and boost corporate profits that led to the use of tetraethyllead in gasoline for which General Motors owned the patent. The additive worked very well but did a tremendous amount of damage to the brains of children exposed to the lead from engine exhaust. Once lead was removed from gasoline there was a gradual reduction in crime with fewer brain damaged children becoming adults.

 

[darkhorse]

So, I must admit, I've been pretty stubborn (maybe ignorant?) on the whole octane issue. I live at 7000ft and just kind of told myself that 87 octane is fine for my 2023 PowerBoost... but it does indeed appear that 91 octane ($0.60 more per gal) really does provide better performance. The gas has the same energy density, but because of the higher octane the engine controller can be more aggressive on timing providing more horsepower.

Since I don't roll that many miles per year... I think I'll just switch over to 91 octane for a while.

Good article here: https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

 

[My 2ND Ford]

So, I must admit, I've been pretty stubborn (maybe ignorant?) on the whole octane issue. I live at 7000ft and just kind of told myself that 87 octane is fine for my 2023 PowerBoost... but it does indeed appear that 91 octane ($0.60 more per gal) really does provide better performance. The gas has the same energy density, but because of the higher octane the engine controller can be more aggressive on timing providing more horsepower.

Since I don't roll that many miles per year... I think I'll just switch over to 91 octane for a while.

Good article here: https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

Interesting article.

 

[wayfarer556]

So, I must admit, I've been pretty stubborn (maybe ignorant?) on the whole octane issue. I live at 7000ft and just kind of told myself that 87 octane is fine for my 2023 PowerBoost... but it does indeed appear that 91 octane ($0.60 more per gal) really does provide better performance. The gas has the same energy density, but because of the higher octane the engine controller can be more aggressive on timing providing more horsepower.

Since I don't roll that many miles per year... I think I'll just switch over to 91 octane for a while.

Good article here: https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

Besides the benefits of 93 vs 87 in our 3.5 Twin Turbos, the computer literally provides better tuning when it detects octane level. So you *will* get a benefit. Whether or not you notice it may be a different story, but for me personally I can definitely notices a difference.

 

[HammaMan]

The higher the compression ratio of a gas engine the more likely there is to be pre-ignition of the fuel when it is injected into the hot cylinders. The 35L engines have a compression ratio that is engineered for 87 octane rated gasoline. Ford recommends using 93 octane when towing to minimize pre-ignition when the engine is working harder to deal with the greater overall load and generating more heat (which is why for towing a larger capacity radiator is needed).

There was a problem with detonation with direct injection engines and a team headed up by oak ridge national laboratory --- it was determined part of the cause was the fuel mixing with the engine oil on the cylinder bore being set off by the piston rings interacting with fuel and oil mix at the cylinder wall on the compression stroke. Lake Speed Jr was on that team. After the research was published, new formulations / standards began development. Interesting topic to listen about regarding the LSPI (low speed pre ignition).

The API SP and ILSAC GF6 standards were published after this research was conducted. GF7 is currently being set and will be published early next year. Crazy to think that oil was responsible for detonation to the point where ORNL got in on the research.

Samples of LSPI damage

 

[BMCGC]

Since I don't roll that many miles per year... I think I'll just switch over to 91 octane for a while.

$22 a tank for an extra 20hp on a truck that you pretty much just use as a DD?

That same $22 will buy you two shares of Ford stock.

 

[FaaWrenchBndr]

Once lead was removed from gasoline there was a gradual reduction in crime with fewer brain damaged children becoming adults.

So you’re saying today’s problems is because they started putting lead back in gasoline?

 

[Marcsrx]

Having owned turbo cars since the early 2000's, heavily modified and stock, the thought of 87 octane in a twin turbo V6 makes me cringe.

Any modern ICE performance car requires 93 octane. All of Fords HP/TQ, towing and payload specs, fuel economy etc were no doubt achieved with 93 octane as well in order to show the highest possible numbers.

I get it can accept 87 octane. Technically any forced induction vehicle can if you pull enough timing and boost. You're intentionally neutering your truck. On top of the engine having to compensate for knock which ideally would be 0. More boost, more timing equals more power and higher efficiency, if you can afford a 70k truck I'd think you can afford premium fuel. If you wanted 87 octane in my opinion you should've gotten the 5.0.

 

[Calson]

As I already stated the octane is determined by the compression ratio of the gas engine and nothing else. Higher compression leads to more pre-ignition and with a diesel engine with it very high compression ratio even diesel fuel can be ignited inside the cylinders.

Altitude was a factor with carburators and some need different jets to function well where the air was thinner or needed superchargers. With fuel injection this is not the case as the fuel to air ratio is regulated.

As a teenage I bought and read Colin Campbell's book "The Sports Car: Its Design and Performance" and although it was first published in 1954 it is still quite informative. Today's cars have computer controlled fuel injection and electronic spark control but are otherwise unchanged over the past 100 years.

During WW II the Germans were surprised at the performance of British fighter planes until they were able to investigate a plane on the ground and learned that the engines were using 100 octane gas and so could use a higher compression ratio in the cylinders and produce more power. The Rolls-Royce supercharged engines could have a higher compression ratio thanks to the availability of 100 octane aviataion fuel.

For the past 30 years the use of turbo chargers is the best way to increase horsepower while having maximum fuel economy with smaller engines. A sedan can travel at 70 mph and needs only 15 horsepower to maintain its speed as with the Citroen cars. The trick is to be able to provide more power for acceleration when needed and that is where turbochargers or electric motor assist with a hybrid design, come into play.

 

[FaaWrenchBndr]

Artificial displacement

 

[Marcsrx]

As a teenage I bought and read Colin Campbell's book "The Sports Car: Its Design and Performance" and although it was first published in 1954 it is still quite informative. Today's cars have computer controlled fuel injection and electronic spark control but are otherwise unchanged over the past 100 years.

This is not true. We have variable cam timing and overhead cams, more valves per cylinder, exotic alloys in heads and engine blocks, catalytic converters, lead free fuel and ethanol in all pump gas, direct injection, O2 sensors, knock sensors, ethanol sensors, MUCH MUCH more efficient turbos, synthetic oil, higher compression ratios, many more gears in transmissions, higher speed limits etc.

 

[FaaWrenchBndr]

This is not true. We have variable cam timing and overhead cams, more valves per cylinder, exotic alloys in heads and engine blocks, catalytic converters, lead free fuel and ethanol in all pump gas, direct injection, O2 sensors, knock sensors, ethanol sensors, MUCH MUCH more efficient turbos, synthetic oil, higher compression ratios, many more gears in transmissions, higher speed limits etc.

I agree…..Calson is just a WEE bit behind. Engines have advanced DRASTICALLY

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