93 Octane and higher

[chief135smitty]

Is there an advantage to running higher Ocatne fuel than 93 in the GT350? Since the dyno numbers have been released a lot of people are asking what numbers would have been posted if they had used 93. I understand a higher octane is needed to prevent detination and using a higher octane rating on a car that only requires 87 is a waste of money. So is it a waste of money to run higher than 93 or could you get some more power from a racing fuel? Just thinking about those couple of tanks a year for track days.

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[Hack]

On a hot enough day I wouldn't be surprised if you get gains from higher octane. In cool ambient temperatures there probably won't be a difference.

 

[Helmet]

Is there an advantage to running higher Ocatne fuel than 93 in the GT350? Since the dyno numbers have been released a lot of people are asking what numbers would have been posted if they had used 93. I understand a higher octane is needed to prevent detination and using a higher octane rating on a car that only requires 87 is a waste of money. So is it a waste of money to run higher than 93 or could you get some more power from a racing fuel? Just thinking about those couple of tanks a year for track days.

The octane ratings the manufacturers recommend are usually minimal octane ratings

 

[Myshelby3425]

A few more hp with 93 but if you decide to run e85 there is a nice jump in HP.


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[krt22]

A few more hp with 93 but if you decide to run e85 there is a nice jump in HP.


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Not so sure about that with the GT350, especially untuned

 

[Lucky7s]

Wha??? E85 has less power per gallon of fuel than Gasoline.

Now if you are running a Turbo with lots of Boost, Sure! Allows for high boost level because it burns so much slower and cooler.

1 gallon of E85 has 73% to 83% of the energy of one gallon of gasoline
(variation due to ethanol content in E85).

1 gallon of E10 has 96.7% of the energy of one gallon of gasoline.
(which is what most of us buy at the pump)

 

[flaps]

Wha??? E85 has less power per gallon of fuel than Gasoline.

Now if you are running a Turbo with lots of Boost, Sure! Allows for high boost level because it burns so much slower and cooler.

1 gallon of E85 has 73% to 83% of the energy of one gallon of gasoline
(variation due to ethanol content in E85).

1 gallon of E10 has 96.7% of the energy of one gallon of gasoline.
(which is what most of us buy at the pump)

Yes but the stoichiometric air:fuel ratio is 9.8:1 for E85 compared to 14.7:1 for gasoline, so you can put a lot more fuel into the engine. So even if E85 only has 78% of the energy, it can still make 17% more power because a lot more fuel will get injected.

Obviously you would have to tune it for this though.

 

[bpracer]

Not so sure about that with the GT350, especially untuned

I agree, I doubt E85 would help on an NA engine, and Ford says the GT350 is not E85 compatible. If I was running a supercharger or turbo than yes, I would tune a car to use E85. You want the least amount of octane that the engine can use without detonation. Lower octane fuel burns faster, in general, than high octane and can give more power on many engines.

There are fuels that are highly oxygenated that can add power, that may be fine on a motorcycle, but pretty expensive for a car track day. I have used higher octane fuel 110 low lead in previous race cars more as insurance against lean conditions rather than as requirement (and it smells good!)

Learning how to brake better and get on the power earlier will get you around a track faster than spending $5/gallon more for race gas.

 

[Myshelby3425]

Not so sure about that with the GT350, especially untuned

Well with a tune of course.. Your not benefitting from running race gas and no tune. So 93 would be it


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[bpracer]

Yes but the stoichiometric air:fuel ratio is 9.8:1 for E85 compared to 14.7:1 for gasoline, so you can put a lot more fuel into the engine. So even if E85 only has 78% of the energy, it can still make 17% more power because a lot more fuel will get injected.

Obviously you would have to tune it for this though.

I think more than a tune, new injectors and fuel pump to pump 30% more fuel.

 

[Myshelby3425]

I think more than a tune, new injectors and fuel pump to pump 30% more fuel.

Yea most probably injectors as well but it does pick up great power


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[chief135smitty]

Yeah it is expensive to run, but I think on an occasional weekend it is nice to splurge just for the smell factor. It reminds me of being at the airport smelling the 100LL.

BPRacer you are right my skill level with those 3 pedals and that round thingy are not up to par. Much practice ahead.

 

[Mountain376]

Well with a tune of course.. Your not benefitting from running race gas and no tune. So 93 would be it


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Not true. You will be up on power slightly, but that's not the thing you'd notice from running higher than 93. What you'll notice the most is the engine running super smooth, nearly in every instance. The engine will be running much closer (depending on fuel octane increase) to its max tuned potential at every point of the curve.

In my 2012 GT I once put in about 6 gal of 110 race fuel (not recommended due to the lead content and cats not liking that). This was in the middle of Michigan summer (>60% humid, temp above 75F) and on a 100% stock, 12k mile car. The engine just felt strong everywhere, in any gear, at every load. The engine felt the same as it would on a crisp, fall morning or evening. I'd say stronger at certain rpm's and driving conditions.

 

[mustang_lurkers]

526hp is not enough for you guys????

 

[Myshelby3425]

526hp is not enough for you guys????

Hell no especially with the numbers it's putting out.


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