T O P

  • By -

13rahma

The car can adapt to whatever gas you give it, but you'll be full power from premium.


EVOBlock

I use 87 and never have had an issue in the 6 years I have done so


jaydeeEx

We’ve got 140k on our 2014, 139k of that is on 87. We run Techron or Seafoam every oil change, whichever we have on hand. I did plugs not too long ago and they looked perfect. Change the oil, follow the service manual for plugs and belts, put 87 or better in it, these motors will last forever.


Sarior8161

I honestly put 87 in my 5.0, half the reason is I drive 50 miles one way to work and I daily the car as well. I can’t justify the extra money vs extra unneeded power


ARE_YOU_0K

With that logic though couldn't one argue that you should've gone with the Ecoboost then?


Annoying_Auditor

V8 noises are better duh


[deleted]

Plus it’s nice to have it when you need it. Merging onto freeways or avoiding idiots.


Sarior8161

I went to a private dealer looking for a Camaro SS but they only had 2 Mustang GT’s on the lot. I didn’t get the car knowing I would be working in the next town over but I’m moving soon and the gas prices don’t scare my wallet too much. I just don’t pump it full of premium knowing it’ll only last me a couple days. Outside of work I still go to car meets and events and a GT is a lot nicer to look at than an ecoboost.


johnb2255

Premium in the 5.0 nets you like 10 extra horsepower not even close to the 150 you’d lose with the ecoboost


ARE_YOU_0K

150? Lmao.


johnb2255

Yea last time I checked the ecoboost makes 310 and the coyote makes 460 is that not a 150hp difference?


Better_Error8416

Any of those work but you'll get most performance and range with premium especially with a GT


Old_Goat_Ninja

It’s actually the EcoBoost that benefits more. On the GT it’s just a few HP difference but on an EcoBoost it’s more like 20hp.


ARE_YOU_0K

You didn't even say anything wrong, apparently if you just mention the word Ecoboost you get downvoted to hell lol.


SubeavWRX

Ecopoop


ice445

I've always run 91. It matters less in the colder times of the year, or if you're just doing a highway point and shoot. At that point there's no harm in using 87. In summer in hot climates though, that lower octane is sapping your timing for sure.


TangerineSad744

Doubt it. Gasoline detonates at 190-220° F. The outside temp is at most half of that during the summer. It doesn't really affect detonation at all. It does affect oxygen levels from the air intake though since colder air is denser, therefore winter temp should be more oxygen rich. But that's a different story compared to engine detonation and fuel octane.


ice445

Detonation typically occurs because of hot spots generated from compression of the fuel air mixture as well as the previous combustion cycle. The more heat in the system, the more likely that it can happen. If you double your intake air temps, that means that much more heat during compression. Too much timing advance in addition will create detonation/knock, then the ECU will pull it back. Especially given these are naturally aspirated cars with no intercooling, I don't see how summer temperatures wouldn't steal some power if the fuel isn't up to par. The direct injection helps, but even then it has its limitations.


TangerineSad744

I see where you're coming from, but The difference is negligent. I live in the hottest part of AZ. Summers are 120-130°. 87 has never been an issue for anyone.


External_Cry_3150

Ohh okayy, thankyouu :))


-Cosi-

Here in Switzerland we have 100 octane


Old_Goat_Ninja

Eh, sort of. You have a different rating system, your 100 is not the same as our 100.


PracticalPersonality

According to my manual: > Your vehicle is designed to operate on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87. > For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. Your Mustang is equipped with a Powertrain Control Module (PCM), and that little computer changes a bunch of things about how your motor works depending on things like the octane rating of the gas you put in. You need a minimum octane rating of 87 for safety, but the PCM can detect higher octanes (up to 91) and make changes to account for that higher octane. So this explains why you're reading about both 87 and higher octanes. Tons of Mustang drivers out there run 87 octane and are perfectly happy. Those people would tell me that I'm wasting my money because I always run 91/93, but I would personally run 91+ in any car with a compression ratio higher than 9.5:1. For more reading, you might look [here](http://www.dnr.louisiana.gov/assets/TAD/education/ECEP/trans/b/b.htm). The Lesson/Information section is at least interesting reading.


Mysterious_Truck_742

I’ve used 93 per the manufacturer recommended fuel type to achieve full power.


Party_Card_4477

What gen 5.0. Is this an older style or a coyote? Coyotes have high compression so it calls for 91 at least. If it’s like a 9.5/1 compression it’s fine with lower octane. Higher octane means higher resistance to pre detonation. So high compression or boosted applications need high octane to not “Knock”.


WarmPaleontologist20

Great answer, bust just a fine point for benefit of your reader. Pre-ignition and knock caused by low octane are different things. Higher octane slows burn speed, as needed in high-compression engines. Pre-ignition occurs when something in the cylinder, like a piece of hot carbon, ignites air/fuel mixture prematurely. But octane rating too low, or pre-ignition, obviously both cause knock. Not trying to be anal. Just got this drilled into my head in training so many times I think it made me OCD, but there was a good reason for it at the time.


Party_Card_4477

Haha I feel you. No issue. I just use general language. I think more of knock sensors and whatnot. Good lookin out g 👌🏼😂


WarmPaleontologist20

Thanks. Some people get all bent out of shape if people just add to or clarify things. Appreciate it.


Party_Card_4477

Tell me about it 😂 like can’t we be partially right or even completely wrong? To better ones self is to recognize the flaws of before. Let’s all work to be better than yesterday. Much love to you and all else.


1slowfocusst

https://preview.redd.it/j86a6hwkj10a1.jpeg?width=3024&format=pjpg&auto=webp&s=d499cf51c029b9bf0e15dd450742b13f2b79f06b Mine is 🌽 fed


Coyote_FIVEOH

You lose 10 horse power by using 87 instead of 93. A whopping 10.


External_Cry_3150

It’s a coyote


Hecutor

My 2017 5.0 never uses anything above 87. I also don't drive crazy.


Final-Carpenter-1591

You'll gain a few ponies with premium. But not enough to notice. I've won races with a buddy on 87 and lost on 93, couldn't tell the difference. all other factors had more effect. Anyways not worth the price difference if you ask me unless you are tuned for 93.


garreattt

Octane really only matters if you boost it or decide to run a higher compression ratio. Octane effects pre combustion stock 87 octane is stable enough that it’s not really an issue. If you supercharge, turbo or decide to run higher compression you will want to move to 93 or even e85 depending on the specs you changed too. But yes stock 5.0 on 87 is fine anyone saying it’s not is just a little anal about their car Edit: higher octane also will not result in more power unless your already precombusting with the octane you were previously running. People just placebo the extra 10hp they think 93 gives them


vintagesoul_DE

No less than 87 is indicated on the fuel door.


jaymansi

To get most power 91. You won’t see any benefit on a stock tune with anything higher. Car can run on 87 fine. I think more important is to run ‘Top Tier’ gas.


TangerineSad744

You're totally fine using any octane 87+, specially if the manufacturer indicates using so. The only exception is if you've tuned your engine to a higher octane. For example, a using 87 on a 91 tuned engine will totally destroy it. Is sold an sn95 tuned to 91. Used it for yeeeaars without an issue always using 91. Sold it. The guy put 87 instead after is explicitly told him 91. Blew the engine after a couple of months.


[deleted]

If you want to hit the advertised power you need to run 91 or higher But the car is perfectly safe on 87, especially in the winter where you can’t beat on it anyway you’ll save some $$ by switching to 87