Normal or Premium Gas

[Adeel3466]

Wanted to know what you all put in your Mustang GTs. I looked up the s550 owners manual and it said that it is designed for 87 but for optimal performance to use 91. Is it better to just go 91 all the time or maybe just use 91 when going to a track or doing other performance tests? What are the pros and cons of each? I have a GT performance pack on order.

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[Back2Gas]

It depends. If you want to utilize the full performance of the Engine then premium. Otherwise regular would work fine.

 

[Jrws1014]

Anyone ever use E88? The gas door shows it can handle E0-E15. So I’m curious is going to E-88 (which is 15% ethanol) will harm the engine. Some days you just want to save that $1 per gallon….

 

[Skye]

https://www.mustang7g.com/forums/threads/premium-fuel-for-mustang-dh-to-be-more-expensive.156717/

I want to utilize and appreciate all my car has to offer. Sporting compression ratios of 12:1 (V-8) and 10:1 (EcoBoost), it's also a step towards goodness to use the best. I only run Premium, Top Tier gas (Shell).

 

[krisk]

Anyone ever use E88? The gas door shows it can handle E0-E15. So I’m curious is going to E-88 (which is 15% ethanol) will harm the engine. Some days you just want to save that $1 per gallon….

I assume you are referring to Unleaded 88, which is just another name for E-15. As long as the care is approved for E-15 then it should be safe in the car. However, with the higher ethanol content you will likely experience worse fuel efficiency.

 

[krisk]

Wanted to know what you all put in your Mustang GTs. I looked up the s550 owners manual and it said that it is designed for 87 but for optimal performance to use 91. Is it better to just go 91 all the time or maybe just use 91 when going to a track or doing other performance tests? What are the pros and cons of each? I have a GT performance pack on order.

I always use premium (93 Octane in my area). I am no expert, but from prior research my understanding is the car has optimal performance using at least 91 octane, but is safe down to 87. Essentially, the car has systems that monitor knock and will retard timing to prevent knock if detected. Generally this occurs when running lower octane fuel, and will result in reduced power. In everyday driving I doubt you could even tell a difference in performance, but it likely would show lower horsepower on a dyno when running lower octane.

I’ve heard others say that it takes the computer some time of running the higher octane to adjust timing back to optimal performance when switching from lower octane back to higher. Whether this is true or not, I have no idea. What I do know is if you are running 87 octane normally, and want to switch to higher octane for track or performance use, then you’ll have to get the tank to less than 1/3 full before filling with 93 octane to get your overall octane rating back to 91. For me, I just prefer to keep premium in it all the time.

 

[LETHAL]

Top Tier premium is more then just an octane rating. There are detergents and additives that help with keeping the top end of your motor (valves and combustion chamber) clean. I'll pay the extra money to get the most out of my vehicles. Esp the EcoBoost vehicles.

 

[Bikeman315]

If you can’t afford premium go buy a Prius.

I’ve always wanted to say that!

Seriously, this is around the 100th thread on gas octane and every single one of them is the same. Ford‘s performance and fuel economy numbers are based on premium. Therefore that’s what’s “recommended”. But, as been said before, regular is exceptable. So using regular will not harm the engine but why buy a car like this and then water it down by not using what Ford recommends? I only use 93 Top Tier, but you do whatever is best for you.

 

[mcky2011]

Wanted to know what you all put in your Mustang GTs. I looked up the s550 owners manual and it said that it is designed for 87 but for optimal performance to use 91. Is it better to just go 91 all the time or maybe just use 91 when going to a track or doing other performance tests? What are the pros and cons of each? I have a GT performance pack on order.

To beat the dead horse, super.
Performance engine = performance fuel.

 

[Q6543]

I have a more of a racing background, people need to realize the modern science miracle of being able to put 87 octane in a 12:1 engine and not detonate itself to death from mile one.

even 93 octane really isn’t enough… that’s why E85 pick up so much HP… the engine can finally get the timing it needs safely.

i know people will say it’s ok to run 87… just realize that your engine running normally is detonating and relying on knock sensors, ignition and cam timing tricks to keep from eating itself in no time.

 

[LETHAL]

I have a more of a racing background, people need to realize the modern science miracle of being able to put 87 octane in a 12:1 engine and not detonate itself to death from mile one.

even 93 octane really isn’t enough… that’s why E85 pick up so much HP… the engine can finally get the timing it needs safely.

i know people will say it’s ok to run 87… just realize that your engine running normally is detonating and relying on knock sensors, ignition and cam timing tricks to keep from eating itself in no time.

Even amongst premium brands there are differences as I stated above in another post. When I had my 18GT and was tuned by Lund, they looked at my logs and capped the advance at 25*, WHILE MANY WERE SEEING 28*-30*. I was told even the top tier around my area must be so/so.

 

[Smaaron]

Sounds like premium fuel makes the biggest difference for ecoboost engines
https://www.steeda.com/87-vs-93-octane-for-mustang
Edit: just realized Lethal already mentioned that. Article says it’s only about 2% difference in v8 and maybe ~12% in ecoboost.

 

[GrabberBlueFan]

Sounds like premium fuel makes the biggest difference for ecoboost engines
https://www.steeda.com/87-vs-93-octane-for-mustang
Edit: just realized Lethal already mentioned that. Article says it’s only about 2% difference in v8 and maybe ~12% in ecoboost.

Wow, big difference for ecoboost! I’ll be running premium, but now have to look into the Top Tier Shell gas.

 

[Bikeman315]

Wow, big difference for ecoboost! I’ll be running premium, but now have to look into the Top Tier Shell gas.

The 2.3 EB should have had a requirement for premium, not a recommendation. Big, big difference. And that was on my 15’ EB. As far as brand, I use Costco. It’s Top Tier and you never have to worry about sitting in their tanks for long. But if there is no Costco around I do seek out a Shell station.

 

[GrabberBlueFan]

The 2.3 EB should have had a requirement for premium, not a recommendation. Big, big difference. And that was on my 15’ EB. As far as brand, I use Costco. It’s Top Tier and you never have to worry about sitting in their tanks for long. But if there is no Costco around I do seek out a Shell station.

Thanks for the info. I use Costco when I’m close (it’s about 20 min away), but never realized the Top Tier meant anything. I hardly ever used Shell, but those two will be my top picks now. Thanks again.

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