Does premium gas make a big difference over regular?

[TorqueMan]

Wow, so much misinformation in this thread. Your car is electronically speed limited to 126 mph, and it has nothing to do with fuel octane or tires. The reason the car is speed limited is due to cooling. To maintain speeds above 126 mph requires constant boost on the engine, which produces too much heat for the standard radiator. The performance pack--an option intended to make the car track ready--includes a larger radiator to handle the increased cooling requirement that will result from running under constant boost.

Your engine will not knock if you run 87 octane; the powertrain control module incorporates sensors to detect detonation (knock) and alters engine tuning to prevent it. (This goes for the V8 engines as well; if your engine is experiencing audible detonation take your car in for service immediately because something is gravely wrong).

Here's where things get confusing. If you check your owner's manual you'll find 87 octane is the recommended fuel. The engine will not, however, produce the maximum advertised power using 87 octane, but not because the engine is knocking. Remember, the PCM will not allow engine knock because it can cause engine damage. To prevent knock, however, the PCM will retard ignition timing, which will result in lower power output. That's why your owner's manual tells you to use premium fuel for "improved performance" or for "severe duty usage."

How much more power will you get using premium? A good rule of thumb is that you must increase power by at least 10% to feel a difference. My research online suggests the PCM cuts power to around 275 hp when burning 87 octane, which is some 35 hp less than the advertised maximum of 310. Some here have reported feeling a difference in their "butt dyno" when switching to premium from 87 octane, which makes sense since 35 is approximately 11% of 310.

You can install a tune to defeat the speed limiter, but it comes with tradeoffs. Depending on how many miles you have on your car, you may forfeit the remainder of your new vehicle limited warranty. Additionally, any time you demand greater power from an engine you reduce reliability and durability. How much? I can't tell you that, but you can search around on this site and find a poll of people who have blown their ecoboost engines, and almost all of them were running a tune meant to increase power output. Finally, although you will gain the capability of exceeding 126 mph, unless you also upgrade the radiator your stock cooling system cannot handle running for extended periods under boost.

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[GasPedal]

I switched to regular even though I planned on always using 93. Not that much of a difference in acceleration for the $0.50+ difference here v regular. Plus I'm always in traffic so being able to run up 2nd gear feels like lightspeed anyway.

 

[Ebm]

Three suggestions for performance & longevity: 1. Higher octane is always a value, regardless of price. 2. If you have any way to do it, never put ethanol in your car. As a forensic engineer I can assure you that ethanol is evil. 3. Change your oil religiously and use full synthetic oil.

My 2012 GT has 221K miles and still runs as strong as when new, and still gets 26 - 28 MPG on the freeway. In WI I don't have to buy ethanol, and if I ran out I'd walk with a can to get real gas if it was only 50 miles or so.

221k miles? That's like 27k miles a year. You stay on the road eh?
It is good to hear a Coyote lasted 221k miles so far. That's longevity!

 

[Hack]

There's two thought processes here...

1) Why do I need premium gas if I'm just driving my car to work. It seems like a waste of money and it probably is. Just because you own a high performance car doesn't mean you can't be financially conscious.
2) With a car with this much horsepower, you need to run premium fuel. The car will knock with regular gas and you are leaving power on the table.

With that said, would your thought process change if gas was $10 a gallon instead of $3 a gallon? Be truthful. This question probably isn't meant for you. If you can afford a new Viper, you are rich anyways.

That's pretty well said. The other thing about octane is that knock is more likely under certain conditions. If you live somewhere with highs in the 80s and 90s almost every day, then premium might make a noticeable difference.

If you are driving around and by far the most common temperatures are below 70 degrees, it's much less likely that you will notice a difference in power between premium and 87 octane.

When I owned a 2015 GT I tried both and ended up running 87 most of the time. I couldn't tell a difference between 87 and 91 in my normal usage of the car. When I had my GT350 I had to run 91 because that was what Ford recommends for that car. I have access to 93, but I would rarely run it. I typically couldn't tell a difference between 91 and 93 in the GT350.

So for me it's just about not wasting money on something unnecessary. I have no problem paying for fuel, but I'm not going to pay extra for a number that does nothing for me.

 

[Jiki05]

This thread turned into an octane war.

 

[tcman54]

I like TorqueMan's comment very much but....

Even though it appears that one can gain about 10% more horsepower with 93 octane compared to 87 octane the fact of the matter is the car is still limited to 126mph correct?

And to take it one more step, my car is modded with 168mph rated tires, upgraded intercooler, sports suspension, oil separator etc but the fact of the matter is unless a tune is installed to take off the limiter in the program the car still won't go over 126mph.

I thought initially maybe higher octane gas would do the trick but apparently not, maybe for some it might cure knock and make the car "feel" faster but I don't have those problems.

So I guess I either get a limiter delete tune or shut the heck up.

Terry

 

[Hack]

This thread turned into an octane war.

It always does. I prefer to think "octane conversation", but yes people always disagree about octane.

 

[Ginger1]

‘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?

 

[YoloBathsalts]

I like TorqueMan's comment very much but....

Even though it appears that one can gain about 10% more horsepower with 93 octane compared to 87 octane the fact of the matter is the car is still limited to 126mph correct?

And to take it one more step, my car is modded with 168mph rated tires, upgraded intercooler, sports suspension, oil separator etc but the fact of the matter is unless a tune is installed to take off the limiter in the program the car still won't go over 126mph.

I thought initially maybe higher octane gas would do the trick but apparently not, maybe for some it might cure knock and make the car "feel" faster but I don't have those problems.

So I guess I either get a limiter delete tune or shut the heck up.

Terry

Doesn't really matter. Eventually you're going to get pulled over trying to top the car out on public roads and your car will go to impound while you're carted off to con-college.
If you are running an Eco and you are not using 93 you are a pleb. Get the FP tune it's fairly solid.

 

[mustang1]

I like TorqueMan's comment very much but....

Even though it appears that one can gain about 10% more horsepower with 93 octane compared to 87 octane the fact of the matter is the car is still limited to 126mph correct?

And to take it one more step, my car is modded with 168mph rated tires, upgraded intercooler, sports suspension, oil separator etc but the fact of the matter is unless a tune is installed to take off the limiter in the program the car still won't go over 126mph.

I thought initially maybe higher octane gas would do the trick but apparently not, maybe for some it might cure knock and make the car "feel" faster but I don't have those problems.

So I guess I either get a limiter delete tune or shut the heck up.

Terry

Just leave it as is. For the price of a tune and a speeding ticket you can buy a lot of 93 octane.

 

[tcman54]

Ok will research some tunes and in the meantime will try some 93 octane and see if it does anything for me in the "feel" department.

Thanks for the all the replies.

Terry

 

[nastang87xx]

‘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?

Nothing that you listed would provide extra power. Throttle body spacers are a thing of the way way way past. Do you know what a BOV is for specifically? As well as a catch can? Then again if I'm misinterpreting what you're trying to accomplish and looking for just benefit and not necessarily power, a catch can. The other two are completely meaningless especially the spacer.

 

[66Bronc1]

I ran 87 octane in my 2018 GT all the time. It was one of the selling points to me in choosing the Mustang over the Camaro. It is recommended to run 93 octane although you can run 87. 93 octane can be very expensive here is South Florida. Some stations charge 1.00 or more a gallon for it. And you usually can't get it before or after a hurricane. My GT ran OK on the 87 but it started pinging at low RPM. The engine starting making very strange noises at around 4K miles- rattling, knocking. I never tried 93 octane to see if it would cure it, I decided to down size my fleet and traded it in. I now have lesser cars that run on 87 octane just fine and it's readily available so I no longer have to worry about premium fuel. For those of you that the manual suggests to run the 93 octane for maximum performance, I for sure would use it and not use the 87 octane at all.

 

[vnzbd]

Car and Driver this month has a good article on this very subject. They test 4 vehicles. The difference is minor for most producing 0-60 and 1/4 mile testing with approximately a .1 second improvement at 93. The one vehicle that has a major impact is the v6 twin turbo ecoboost pick up truck. Interesting.

 

[Nagare]

Wow, so much misinformation in this thread. Your car is electronically speed limited to 126 mph, and it has nothing to do with fuel octane or tires. The reason the car is speed limited is due to cooling. To maintain speeds above 126 mph requires constant boost on the engine, which produces too much heat for the standard radiator. The performance pack--an option intended to make the car track ready--includes a larger radiator to handle the increased cooling requirement that will result from running under constant boost.

The car is still capable of hitting and sustaining higher speeds without a larger radiator. The tires are not rated for higher speeds, they are the lowest safety factor and the limiter matches that. Performance pack is definitely not a "track" ready option, it is more handling oriented but definitely not for sustained tracking.

Your engine will not knock if you run 87 octane; the powertrain control module incorporates sensors to detect detonation (knock) and alters engine tuning to prevent it. (This goes for the V8 engines as well; if your engine is experiencing audible detonation take your car in for service immediately because something is gravely wrong).

I don't think anyone is really saying the car is going to be knocking like that. What they mean is that the knock sensors are going positive which in turn pulls power (alters the engine tuning as you said). This may be what @bigzyf was misunderstanding too. If you run bad gas, your knock sensors will be going crazy and that can happen even on the stock tune. Doesn't mean you're immediately ruining your engine though.


The rest of what you said is probably valid, but I wouldn't say there is "so much misinformation in this thread".

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