How does your GT run on regular gas?

[Bulldog9]

Lessee, say 4000 mi per yr/18 mpg=222 gallons x .27 cents diff between 87 and 93 = $60.

I'll stick with 93 thank you! I personally did the fill up on the dealer's dime when I picked up my GT in JAN and it got 93 QuickTrip, been running COSTCO 93 since(advertised as 6x the cleaner required to be top tier).

LOL, find the place where 93 is only .27 higher than 87 and I'd agree. It averages between $1 and $1.25 more where I am. I fee sorry for the poor schleps that bought a Diesel for better fuel mileage, they are getting HOSED............

Happy to run regular for my normal around town, commuting and Sunday drives. When I head out to the mountains in a few weeks will feed the 93 juice..........

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[Bulldog9]

That episode of Engine Masters really bothered me. If you are planning to run 116 octane, the engine should be built for high octane - probably 15:1 compression, etc. You can make a lot of additional power if you design the engine for high octane. The Coyote is designed for 87, so it's a different situation.

Yes obviously if the engine doesn't knock on 87 you won't get a benefit from higher octane (all other things such as ignition and valve timing being equal). The Coyote will automatically retard the ignition timing and has the ability to change valve timing on the fly, so it's possible to derive a benefit from higher octane with the Coyote. The Coyote is designed to run well on 87 but can slightly benefit from higher octane. Completely different situation than considering how much power you can make from 116 octane race gas vs. 87.

The Engine Masters episode was just really lazy. They could have built a couple different engines with each optimized for that specific fuel. That would have shown the difference in power you can make with higher octane. But what they did was more like comparing 87 and 93 in a Coyote - you will get very small benefits if anything.

So many variables here, and the 'evidence' was for that car, engine and setup. Some vehicle's ECU's can accommodate for a wide range of octane with wide adjustment to timing, be it ignition, intake tract, or valves as well as the length of fuel pulse to eliminate knock in all but extreme circumstances. The GM and Ford motors clearly state you can run 87, but with a degradation of performance.

Try that in a Supra, or BMW, or Mercedes, or say our old H6 Subaru and it is ping and knock city, and aggressive driving will likely damage the motor. My wallet and I are glad that I can run 87 without worry in my Mustang, and Tundra......

 

[WildHorse]

The Coyote is designed for 87

Designed for 87oct sure. But not optimized-ish for 91oct+ stock tune-wise.

@dpAtlanta still waiting for you to explain it to me.

Please, lemme know if all the tests was running the same stock (non performance tune). Cause I'm about to type a lot of coyote BS.. hate to think I wasted my time. Nah.. won't be a waste, cause it's coyote talk.. not limp d*ck LS talk. K, putting my thoughts together. Annnd go.

Stock tune, gen 1:

91 octane 420hp @ 6500 rpm
87 octane 402hp @ 6500 rpm
91 octane 390lb-ft @ 4250 rpm
87 octane 377lb-ft @ 4250 rpm

Again, super conservative stock tune.
Good enough ? What the f*ck, sure.

The reason why the gen2 coyote can run 87 octane on 11:1 CR is the revised colling jackets around the exhaust valves. When Ford raised the CR ratio to 12:1 in the gen3 those jackets lost some effectiveness even with an extra cooling passage in the head gasket, hence the need for direct injection to cool the cylinder further and allow it to run 87 octane.

Now when you tune for performance, you're not so much giving all the timing salsa at peak load, it's more like giving the whole timing vs load curve a bump up in timing @ WOT especially from 2000 to 5000 rpm @ .15-.50 load, which ironically is the same rpm/load range as to where most of the 'detonation' happens at and where low octane isn't happy at all. I repeat: Not happy at all. Modifiers/Multipliers & knock sensors take care of the rest. So, hence the need for higher octane with a PERFORMANCE tune that makes 60 more coyote-rific HP vs 87oct w/ a stock tune.

That said, if your only making 'a few more horsepower' with 87 vs the world octane champs with a performance tune, well, I think I explained it:

1. Engine Masters must have the most incompetent tuners on the planet.
-------------------- or ------------------------
2. It was a pretty much bone stock LS

So what does all this mean ? Few more HP ? LMFAO. I typed to much.

 

[dpAtlanta]

@dpAtlanta still waiting for you to explain it to me.

My suggestion still stands... watch it yourself and come up with your own argument. I agree with their test methodology and results.

I think you will enjoy their episode.

 

[Hack]

Designed for 87oct sure. But not optimized-ish for 91oct+ stock tune-wise.

@dpAtlanta still waiting for you to explain it to me.

Please, lemme know if all the tests was running the same stock (non performance tune). Cause I'm about to type a lot of coyote BS.. hate to think I wasted my time. Nah.. won't be a waste, cause it's coyote talk.. not limp d*ck LS talk. K, putting my thoughts together. Annnd go.

Stock tune, gen 1:

91 octane 420hp @ 6500 rpm
87 octane 402hp @ 6500 rpm
91 octane 390lb-ft @ 4250 rpm
87 octane 377lb-ft @ 4250 rpm

Again, super conservative stock tune.
Good enough ? What the f*ck, sure.

The reason why the gen2 coyote can run 87 octane on 11:1 CR is the revised colling jackets around the exhaust valves. When Ford raised the CR ratio to 12:1 in the gen3 those jackets lost some effectiveness even with an extra cooling passage in the head gasket, hence the need for direct injection to cool the cylinder further and allow it to run 87 octane.

Now when you tune for performance, you're not so much giving all the timing salsa at peak load, it's more like giving the whole timing vs load curve a bump up in timing @ WOT especially from 2000 to 5000 rpm @ .15-.50 load, which ironically is the same rpm/load range as to where most of the 'detonation' happens at and where low octane isn't happy at all. I repeat: Not happy at all. Modifiers/Multipliers & knock sensors take care of the rest. So, hence the need for higher octane with a PERFORMANCE tune that makes 60 more coyote-rific HP vs 87oct w/ a stock tune.

That said, if your only making 'a few more horsepower' with 87 vs the world octane champs with a performance tune, well, I think I explained it:



So what does all this mean ? Few more HP ? LMFAO. I typed to much.

Are people really getting 60 HP from a tune? And are your numbers from real dyno runs, or just made up? I don't think 87 vs 91 is 20 hp. More like 5.

Edit: on Engine Masters 91 octane made 0.2 hp more than 87 in an LS engine.

 

[WildHorse]

Are people really getting 60 HP from a tune?

vs 87 octane w/ a stock tune.

 

[Hack]

vs 87 octane w/ a stock tune.

Do you have some evidence such as 1/4 mile timeslips before and after? That's a lot of power to gain. I might have to get a tune if I could really gain that much.

 

[WildHorse]

Do you have some evidence such as 1/4 mile timeslips before and after? That's a lot of power to gain. I might have to get a tune if I could really gain that much.

look above. 20 horse difference between 91 vs 87 stock tune. Performance 91 tune is around 30-35. 40 on the very high side. <- I picked that, cause, I'm a optimistic kind of mofo haha

 

[Hack]

look above. 20 horse difference between 91 vs 87 stock tune. Performance 91 tune is around 30-35. 40 on the very high side. <- I picked that, cause, I'm a optimistic kind of mofo haha

EM got 0.2 HP from 91 vs. 87 on an LS making similar power as the Coyote - so 20 HP is a pretty large claimed number. Hard to believe. I'm certain that if the LS had made 20 HP from the change EM would have reported it. I guess I'm not that optimistic and maybe a little curmudgeonly - if that's a word.

 

[WildHorse]

Hard to believe.

Then don't. Actually please don't. Cause you know. Comparing a LS to a coyote

 

[Fastoldman]

I feel for you guys on the Coasts as the spread for us in a lot of the Midwest seems to be in the 30-60 cent range from 87 to Premium. I actually fill up at one Station that is 93 Octane and it is usually only around 30 cents higher than the plebeian 87 stuff. It was at $4.04 the other day, which is high but nothing compared to the boys and girls in California!

 

[MotoMike]

LOL, find the place where 93 is only .27 higher than 87 and I'd agree. It averages between $1 and $1.25 more where I am. I fee sorry for the poor schleps that bought a Diesel for better fuel mileage, they are getting HOSED............

Happy to run regular for my normal around town, commuting and Sunday drives. When I head out to the mountains in a few weeks will feed the 93 juice..........

I feel for you guys on the Coasts as the spread for us in a lot of the Midwest seems to be in the 30-60 cent range from 87 to Premium. I actually fill up at one Station that is 93 Octane and it is usually only around 30 cents higher than the plebeian 87 stuff. It was at $4.04 the other day, which is high but nothing compared to the boys and girls in California!

Just checked gasbuddy and right now here in west GA the spread between 87 and 93 at the COSTCO where I fill up is 30 cents. I guess we're lucky it isn't more. i will continue using 93 in my 5.0's.

 

[Dfeeds]

EM got 0.2 HP from 91 vs. 87 on an LS making similar power as the Coyote - so 20 HP is a pretty large claimed number. Hard to believe. I'm certain that if the LS had made 20 HP from the change EM would have reported it. I guess I'm not that optimistic and maybe a little curmudgeonly - if that's a word.

It is a word, and you are. Keep in mind that 20 hp really isn't that large, all things considered.

You're also comparing apples to oranges. An LS engine running 10.**:1 compression, without vvt, and relying on displacement for torque won't benefit from higher octane (even tuned for it) like a smaller displacement engine, that relies on 12:1 compression and vvt to make all of its low end grunt, would benefit. That's like saying higher octane fuel is snake oil because you ran it in your old, 9:1 CR, N/A pushrod 302 and were down on power.

If an engine's potential can be fully realized on 87 octane, then bumping it up to 93 won't gain anything. The exception may be if ethanol is used because it will keep combustion temps lower and that has its own set of benefits.

All of that being said, a .2 HP difference is incredibly suspect. You can run the same engine, back to back with zero changes, and have a greater variance in power.

 

[5speed]

Just to weigh in; I lived in NC for years and worked near the tank farms for Colonial Pipeline. I had a friend that worked there. All gas comes through the pipe from the refineries in LA the same. The only exception at that time was Amoco (BP) Unleaded premium which was white gas and they would put air in the lines to separate it from the rest. The difference is when they were pumped into the holding tanks, quality gas such as Mobil and Exxon as examples, would put additives into the fuel which is really what separates the junk from the name brand. What those are and how they help, besides detergents I am not knowledgeable enough to say.

 

[Hack]

Then don't. Actually please don't. Cause you know. Comparing a LS to a coyote

That's a good point. The LS is very low tech compared to the Coyote. Cam timing can only be adjusted as an entirety rather than intake and exhaust getting separate adjustments. So there is less flexibility WRT dynamic compression ratio.

It is a word, and you are. Keep in mind that 20 hp really isn't that large, all things considered.

You're also comparing apples to oranges. An LS engine running 10.**:1 compression, without vvt, and relying on displacement for torque won't benefit from higher octane (even tuned for it) like a smaller displacement engine, that relies on 12:1 compression and vvt to make all of its low end grunt, would benefit. That's like saying higher octane fuel is snake oil because you ran it in your old, 9:1 CR, N/A pushrod 302 and were down on power.

If an engine's potential can be fully realized on 87 octane, then bumping it up to 93 won't gain anything. The exception may be if ethanol is used because it will keep combustion temps lower and that has its own set of benefits.

All of that being said, a .2 HP difference is incredibly suspect. You can run the same engine, back to back with zero changes, and have a greater variance in power.

I'm sure they ran multiple sessions over and over and averaged them. That's typically what they do. Basically it means that the engine didn't knock on 87, so 93 was the same.

So how much a Coyote gains depends on how much it knocks on 87 (or how much it has to adjust from peak power settings to remove knock with 87). If it doesn't knock when running 87, then it won't gain anything with 93. I've always said I think on a hot day there might be some benefit, but when it's cold you won't notice. But I could also believe 20 hp, since 5% is a small enough change that I might not be able to tell a difference.

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