Does premium gas make a big difference over regular?

[boB]

Octane does not equal power, UNLESS your engine is tuned to require higher octane. Putting 94 in an engine tuned to run 94 will put out less power if you dump in 91, due to the knock sensor having to intervene when a knock event takes place.

If your GT isn't tuned, you will experience maximum performance your car is capable of while running octane as low as 91, due to the knock sensor just being along for the ride, never having to cut power. The octane itself is not producing more power.

Make sense?

If we don't believe Ford when they specify 5W-20 then why would we believe Ford when they note that 91 octane is all we need? ;)

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[boos550t]

I've always put premium in my GT but when i had my ecoboost i can definitely tell a difference between 87 and 93, it is minor, but it is there. Daily driving though staying under 2k rpm cruising highway speeds you are just throwing money away with 93

 

[MikeHTally]

Why bother with regular? It’s a performance car and the yearly cost isn’t that much more between the two. I want max performance when I want it.

Agreed. Besides, the actual fuel cost/mile difference is negligible.

 

[MikeHTally]

‘18 Ecoboost Premium with factory 20” rims and w-rated tires. Bone stock other than strut tower brace (garbage NJ roads) and kn air filter.

Butt dyno seems to favor 94 Valero gas.

Would throttle body spacer, blow-off valve, and/or catch can along with 92 or 94 gas give most bang (pun intended) for the buck?

The spacer will add a whistle...

 

[MikeHTally]

Observations are based on the center dash cluster readings.

How are you logging - manual log as in hand weitten based on data directly from fueling receipts? Maybe I should try that method?

The computer is drastically optimistic. My last tank, the computer reported just under 24 mpg. The actual was 21.74. That same computer "deception" applies to my Ram, my Speed 3, and the 300C. I measured the Mazda's - it averaged 11% high.

For those interested, fuelly.com is a handy tool for tracking mileage.

 

[Qcman17]

Octane does not equal power, UNLESS your engine is tuned to require higher octane. Putting 94 in an engine tuned to run 94 will put out less power if you dump in 91, due to the knock sensor having to intervene when a knock event takes place.

If your GT isn't tuned, you will experience maximum performance your car is capable of while running octane as low as 91, due to the knock sensor just being along for the ride, never having to cut power. The octane itself is not producing more power.

Make sense?

Thx yes it makes sense. So I'll rephrase my question can the stock tune utilize the 94 by advancing the timing more than 91? Does the tune scale up enough to do anything. Or should I just run 91 in the GT & not bother with any higher octane?

 

[Qcman17]

please run premium in your 5.0s

Ugh I am I'm just asking if a higher grade premium does anything more than the lower grade premium (91).....

 

[IPOGT]

I notice the difference even with my V6 dodge minivan. Smoother and better milage. Feels a little more responsive as well.

 

[IPOGT]

Ugh I am I'm just asking if a higher grade premium does anything more than the lower grade premium (91).....

You're expecting a simple answer to a complicated question. Many variables. In some cases one or two octane points can mean the diff between a blown engine and a great run.

 

[Deleted member 35644]

Everything I've seen says 91 octane is what Ford used to achieve their stated HP. Short of asking a Ford engineer, there is no way to tell if they also tried 93 and got better results, but chose not to state them. You'd need some dyno time to prove otherwise.

 

[IPOGT]

You're expecting a simple answer to a complicated question. Many variables. In some cases one or two octane points can mean the diff between a blown engine and a great run.

If your car is tuned just get the highest octane you can. Better safe than sorry.

 

[boB]

I notice the difference even with my V6 dodge minivan. Smoother and better milage. Feels a little more responsive as well.

My Honda CR-V gets no turbo boost on 87 octane. None on 89 or 91 either. ;) I have not run my '19 GT on lower than 91 and probably won't except on long trips.

 

[BlackandBlue]

Just to answer an unasked question. 87 will knock in a port 12:1 engine. It is science.

Ford gets around this with direct injection and cooling but the engine will knock when the port fuel system is in use.

12:1 is just beyond the maximum of 87s stability.

 

[MikeHTally]

Not sure I get why the type of injection affects knock. Knock is pre-ignition. How the air/fuel mixture arrives in the combustion chamber would seem irrelevant.

 

[MikeHTally]

I notice the difference even with my V6 dodge minivan. Smoother and better milage. Feels a little more responsive as well.

Riiiiggghhhhhttttt

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