GT Fuel

[mikes2017gt]

If the car is stock you can get away with 87 octane. Of course, there's 87 octane from a major brand/distributor and there's 87 octane from Bob's Quickee Mart and Bait Stop type stores. The quality of the fuel overall matters as much as it's octane rating. Many folks on this forum have modified Mustangs. Even something as simple as a Ford Performance Power Pack requires premium (91 octane minimum) fuel. Pretty much any tune, even a mild one, is going to require premium fuel. Just something to think about.

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[Zinc03svt]

87 octane probably makes the low-mid range torque pretty flat on a coyote. I can afford to put top tier 93 or E85 in my mustang for best performance and do. Play car and not a daily.

 

[Dr. Norts]

I have a few 5 gallon cans of VP Racing C12 if anyone wants to try it... My CR250 loves the stuff

112 octane and leaded. What could go wrong? Lol

 

[VooDooDaddy]

That's so sad :(

Don't feel too bad for me...

I'm a home renovation project manager. The Mustang doesn't fit that bill very well as a work/DD car. My '16 GT is my car that I plan on having until I'm dead, so keeping the miles down will help me keep it for 20+ years. The upside is the fact that since I rarely drive it, when I do it feels like a special occasion.

Plus I roadrace 200+ hp Ducati motorcycles during the summer months, and after you do that for a few years (I've been doing it since 2003), pretty much every car I could ever drive would feel a bit underwhelming, so there's that too...

 

[Smokey613]

We recently purchased a CPO 2015 GT Premium vert with 31K. It had 87 in it when we test drove it I am pretty sure. I noticed it was not smooth in it’s low speed operation and would buck some. It was simply not smooth. I ran it down to almost empty and filled with BP 93. After about 50 miles it smoothed out. It also was more responsive at lower RPMs and throttle tip in was a lot smoother. It’s had nothing but 93 since and runs great. We just took a 1200 mile round trip and on I-10 I frequently had the cruise set at 80mph and got 24-25.5 using GasBuddy to track my mileage. I do not see me going back to 87. For me the extra cost is worth it.

 

[bootlegger]

I have a few 5 gallon cans of VP Racing C12 if anyone wants to try it... My CR250 loves the stuff

112 octane and leaded. What could go wrong? Lol

Probably not a great thing to try if you still have cats.

 

[bootlegger]

Disclaimer, Gen 1 Coyote. Below is a dyno graph showing the difference between 87 octane and 93 octane. According to the shop, no other changes were made to the car/tune/etc. Similar weather for both passes, carat normal operating temperatures.

Note: 6 RWHP peak difference. Not that much, but look at the difference in the mid range, especially 4500-6000 rpm. Looks to be ~20 RWHP difference in places (corresponding increase in torque, of course).

My butt dyno has verified this.

 

[Darkstar]

I've been using ethanol-free 91 octane at QT. Car runs pretty strong on it. I might get a flex tune if the quality of the E85 improves around here.

 

[Zelek]

Been a while since we had another fuel thread. Surprised it hasn't turned into a massive heated never ending argument yet.

Stock and drive like a granny? 87 octane
Hotter climate, driving it like you stole it? 91/93 octane
Tuned? 91/93 octane or E85
Maximum Effort? E85

 

[tal]

I've got a 2016 GT and I have the $99 Steeda tune loaded. I have a 93oct & 87oct tune. I've tried the 87oct tune and it's pretty good. I still have the tuning from the trans and ring out a few more HP with the 87oct tune. I think the 87 tune is nice because the car isn't constantly fighting to go into the high fuel cell trims (93oct).

I've had both tunes loaded and there is a difference. The 93oct tune definitely has more power but the 87oct tune still has the nice drive-ability of the canned tune.

I'll swap to the 93oct tune here in the spring. If gas gets too high, I simply will reload the 87oct tune.

Here in the Chicago area, the spread between 87oct & 93oct can be $.90 a gallon. Can add up if doin' alot of drivin'!

 

[Severn Wes]

Not cheaping out on fuel. Have four other cars burning premium. Given the statement in the owner's manual, just asking a freakn' question!

Interesting question. Here's my convoluted answer. I have two cars, a 2017 VW GTI with 2.0 L turbo engine (9.6:1 compression ratio), and 2018 GT with 5.0 L Coyote (12:1 compression ratio). In the past, the GTI's were required to run premium fuel, but by the 2017 model year, RUG was fine, albeit with reduced horsepower. I've run the GTI on 87 Octane fuel for the entire original 23,000 miles (all mine) it has accumulated without a problem. That being said, I am on my second tank with the Mustang GT. The first was what the dealer put in which I assume was just 87 octane. The current tank was filled with 93 Octane Sunoco by me. I have less than 400 miles on the GT, but since they recommend at least 91 octane, and taking into consideration its compression ratio compared to the VW GTI, it seems to me to make sense to put the highest octane fuel possible. Modern engines adjust timing to reduce per-ignition knock, but I'm sure the technology is not perfect. The less they have to make adjustments (by running higher octane fuel) the less chance you run in suffering engine damage from pre-ignition knocking. Just my opinion an 2 cents.

 

[bootlegger]

I've got a 2016 GT and I have the $99 Steeda tune loaded. I have a 93oct & 87oct tune. I've tried the 87oct tune and it's pretty good. I still have the tuning from the trans and ring out a few more HP with the 87oct tune. I think the 87 tune is nice because the car isn't constantly fighting to go into the high fuel cell trims (93oct).

I've had both tunes loaded and there is a difference. The 93oct tune definitely has more power but the 87oct tune still has the nice drive-ability of the canned tune.

I'll swap to the 93oct tune here in the spring. If gas gets too high, I simply will reload the 87oct tune.

Here in the Chicago area, the spread between 87oct & 93oct can be $.90 a gallon. Can add up if doin' alot of drivin'!

If I were in Chi-town (still), I would be taking advantage of all that sweet sweet E85.

 

[Zelek]

Interesting question. Here's my convoluted answer. I have two cars, a 2017 VW GTI with 2.0 L turbo engine (9.6:1 compression ratio), and 2018 GT with 5.0 L Coyote (12:1 compression ratio). In the past, the GTI's were required to run premium fuel, but by the 2017 model year, RUG was fine, albeit with reduced horsepower. I've run the GTI on 87 Octane fuel for the entire original 23,000 miles (all mine) it has accumulated without a problem. That being said, I am on my second tank with the Mustang GT. The first was what the dealer put in which I assume was just 87 octane. The current tank was filled with 93 Octane Sunoco by me. I have less than 400 miles on the GT, but since they recommend at least 91 octane, and taking into consideration its compression ratio compared to the VW GTI, it seems to me to make sense to put the highest octane fuel possible. Modern engines adjust timing to reduce per-ignition knock, but I'm sure the technology is not perfect. The less they have to make adjustments (by running higher octane fuel) the less chance you run in suffering engine damage from pre-ignition knocking. Just my opinion an 2 cents.

My 18 Accord is the same way. I run 87 octane in it all day long with the 2.0T. It definitely gains some power for running 93 as it adjusts its timing some, but I don't push mine really hard because well.... It's an Accord. It's a commuter and the pistons and internals were designed to be able to run on the lower octane unlike the Type-R. Mazda's are the same way with high compression (12.5:1) and run 87 octane as well with a unique piston / long tube header design on their Skyactiv platform. Most of these cars are all under 300 HP though unlike the Mustang and are your typical daily sedan drivers. With 465 hp from the factory, I would be running 93 octane at 12:1 compression because I know I'm going to step on the pedal in several occasions.

 

[sonicc]

Been a while since we had another fuel thread. Surprised it hasn't turned into a massive heated never ending argument yet.

Stock and drive like a granny? 87 octane
Hotter climate, driving it like you stole it? 91/93 octane
Tuned? 91/93 octane or E85
Maximum Effort? E85

This.

Now lets get this thread locked up and throw the key away.

 

[michail71]

I second, or 3rd, E85 as well. The car feels dead/broken on 93 octane. It smells nice too.

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