i can’t be the only one who runs regular in a GT right?

[sk47]

Dude my 18 pp1 with the 10r80 was ignition cutting like crazy on 94oct with 15-20% ethanol. Now i can only imagine how much harm you are doing to your engine if you run out of luck one day

The knock sensors must be working full time 24/7 and even if you don't hear it (as minimal it can be) it is bad for your piston ringland and your only looking for an engine failure eventually. And there is no excess in my reaction right here im only warning you that you should at the very least run 91 in this motor. Unlike previous generation this new one is pushing the limit of whats possible to run (compression wise) on street pump fuel. And your not getting 450 hp out of 87oct

The difference is so huge, that 87 octane you barely break tire loose, and on 94 you can do a 360 degree shifting from 1st to 2nd in drag mode if you keep it pinned.

Now you do what you want, its your car.

Hello; There is an issue with the context of your post. First, I am not disputing your experience but am throwing out an issue if you are correct.
I did some checking when shopping for a GT about which octane was required. What i found at more than one dealer and by looking at gas caps on actual cars is that 87 octane is approved. I have also done some checking online. Others in this thread also have stated that 87 octane fuel is OK for the stock V8 Coyote engine. This has been verified by several in this very thread.

Thing is and will be that we cannot have faith in the specs put out by Ford if what you write is correct. I tend to go by the mfg. specs on most everything at least while under factory warranty. On some things for the total time i own a vehicle. If in fact you are correct that a Mustang GT needs at least 91 octane and should have 94 octanes, then the rest of Fords specs come into question.

I had a 1989 Ford F-150 pickup which was good on 87 octanes for a long time. I did start to notice a little ping when under a hard load. So, I began to run higher octane fuel in one tank and 87 octanes in the other tank. It had two fuel tanks. When doing a heavy haul or tow I used the higher octane fuel and things worked out fine until the truck weas totaled with 112,00 miles. So, I had an example of a vehicle needing a bit more octane under some conditions. Of course, that was over 30 years ago and the tech should be much better today. That truck had fuel injection. It may have had a build up of carbon on the inside of the combustion chamber after a few years. I drove it for over 12 years before getting into an accident.

I do wonder about how direct injection will work after many miles. In other types of FI the intake valves are washed by fuel so do not build up carbon deposits. Will it be that like the exhaust valves the intake valves can build up carbon deposits. That seems likely.

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[Angrey]

Hello; There is an issue with the context of your post. First, I am not disputing your experience but am throwing out an issue if you are correct.
I did some checking when shopping for a GT about which octane was required. What i found at more than one dealer and by looking at gas caps on actual cars is that 87 octane is approved. I have also done some checking online. Others in this thread also have stated that 87 octane fuel is OK for the stock V8 Coyote engine. This has been verified by several in this very thread.

Thing is and will be that we cannot have faith in the specs put out by Ford if what you write is correct. I tend to go by the mfg. specs on most everything at least while under factory warranty. On some things for the total time i own a vehicle. If in fact you are correct that a Mustang GT needs at least 91 octane and should have 94 octanes, then the rest of Fords specs come into question.

I had a 1989 Ford F-150 pickup which was good on 87 octanes for a long time. I did start to notice a little ping when under a hard load. So, I began to run higher octane fuel in one tank and 87 octanes in the other tank. It had two fuel tanks. When doing a heavy haul or tow I used the higher octane fuel and things worked out fine until the truck weas totaled with 112,00 miles. So, I had an example of a vehicle needing a bit more octane under some conditions. Of course, that was over 30 years ago and the tech should be much better today. That truck had fuel injection. It may have had a build up of carbon on the inside of the combustion chamber after a few years. I drove it for over 12 years before getting into an accident.

I do wonder about how direct injection will work after many miles. In other types of FI the intake valves are washed by fuel so do not build up carbon deposits. Will it be that like the exhaust valves the intake valves can build up carbon deposits. That seems likely.

The difference is in the compression. At 12:1 compression, the tune can only compensate so much timing before preignition and knock end up hurting your motor. I would say if you're just trying to get down the road and you're not flogging the car, it's fine. But I personally wouldn't mash hard on a 12:1 compression motor on 87.

Just because you CAN do something and even if you get away with it once or 10 times, doesn't mean you should or it's wise or smart.

You can smash random broads from the bar or the strip club with no condom. Maybe you don't end up with HIV or syphilis this time, but it doesn't make it smart or responsible. Eventually you're playing with fire. There's always the guy that claims "I smash randoms bareback all the time" and some people get lucky, but using 87 on a high comp motor for more than just limping to the next station is just begging for a broke motor, a tow truck and frownie face.

 

[m3incorp]

Yikes, no condom. This thread is hitting all aspects of life.

 

[thunderstrike]

When doing a heavy haul or tow I used the higher octane fuel and things worked out fine until the truck weas totaled with 112,00 miles. So, I had an example of a vehicle needing a bit more octane under some conditions.

Agree. When I am going to Moab, UT to do some 4-wheeling my Jeep Wrangler is loaded down with cargo it runs like it's a 4-banger. I will use higher octane for extra assist.

 

[sk47]

The difference is in the compression. At 12:1 compression, the tune can only compensate so much timing before preignition and knock end up hurting your motor. I would say if you're just trying to get down the road and you're not flogging the car, it's fine. But I personally wouldn't mash hard on a 12:1 compression motor on 87.

Just because you CAN do something and even if you get away with it once or 10 times, doesn't mean you should or it's wise or smart.

You can smash random broads from the bar or the strip club with no condom. Maybe you don't end up with HIV or syphilis this time, but it doesn't make it smart or responsible. Eventually you're playing with fire. There's always the guy that claims "I smash randoms bareback all the time" and some people get lucky, but using 87 on a high comp motor for more than just limping to the next station is just begging for a broke motor, a tow truck and frownie face.

Hello; I understand your point. An engine which needs a high octane fuel can be damaged by using a lower octane fuel. That was not my contention. My question is about Ford saying the 87 Octane being suitable which is my understanding. The new direct injection and other tech apparently makes it possible to use 87 octane even in a higher compression engine.
Keep in mind I am always referring to a stock engine without any tune or other modifications.

 

[DougS550]

The difference is in the compression. At 12:1 compression, the tune can only compensate so much timing before preignition and knock end up hurting your motor. I would say if you're just trying to get down the road and you're not flogging the car, it's fine. But I personally wouldn't mash hard on a 12:1 compression motor on 87.

Just because you CAN do something and even if you get away with it once or 10 times, doesn't mean you should or it's wise or smart.

You can smash random broads from the bar or the strip club with no condom. Maybe you don't end up with HIV or syphilis this time, but it doesn't make it smart or responsible. Eventually you're playing with fire. There's always the guy that claims "I smash randoms bareback all the time" and some people get lucky, but using 87 on a high comp motor for more than just limping to the next station is just begging for a broke motor, a tow truck and frownie face.

WTF, Where Are you going with this, YIKES!!

 

[Bikeman315]

WTF, Where Are you going with this, YIKES!!

 

[Helios]

Not that you can't get away with 87 octane, but i blame all the lastest gen coyote engine failures related to the same thing. Piston/Ringland problem

In my opinion most folks see in their manual they can run regular and do it, but its more harmful than great. So like i said you do what you want with your car but don't be surprise if it fails premature down the road

My car been run like i stole it since day 1, always filled with 94 and never ticked or show signs of being about to give up. Coincidence ? I don't know

All i know is 12+ compression on regular is nonsense, honda engines with anything higher than 10.5 comp ratio always required 91 octane. So i go with experience on this

 

[Qcman17]

The difference is in the compression. At 12:1 compression, the tune can only compensate so much timing before preignition and knock end up hurting your motor. I would say if you're just trying to get down the road and you're not flogging the car, it's fine. But I personally wouldn't mash hard on a 12:1 compression motor on 87.

Just because you CAN do something and even if you get away with it once or 10 times, doesn't mean you should or it's wise or smart.

You can smash random broads from the bar or the strip club with no condom. Maybe you don't end up with HIV or syphilis this time, but it doesn't make it smart or responsible. Eventually you're playing with fire. There's always the guy that claims "I smash randoms bareback all the time" and some people get lucky, but using 87 on a high comp motor for more than just limping to the next station is just begging for a broke motor, a tow truck and frownie face.

Wait I can bang strippers bareback but I should not under circumstance run 87 got it!

I would think the fact the car is DI would prevent some preignition from happening with 87 octane despite the 12:1. That said I never go under 91 anyways.

 

[shogun32]

While making a 1,600 mile road trip, I couldn't stomach paying 70 cents premium over the regular gas, so tried using regular.

now since the GT has 24,000 miles, with engine well broken into. Of course, I will purchase 93 premium when Sam's or Costco are near/lines are not long.

you're buying gas wrong. There's Costco's everywhere and you just need to time your gas stops to be before 9am and after 7pm. No lines. Easy peasy. $3.03 regular, $3.35 for 93

 

[ZeroTX]

My car is on its first (ever) tank of gas. It was filled up by the dealership. What are the chances it's not regular? hehe. I think about 0. But I won't be driving it hard during the first tank. Needs break-in.

 

[Angrey]

As if the typical concerns weren't enough, if you're banking on direct injection to save you, here's some food for thought.

Yes, there's evidence that DI helps to control preignition and detonation. HOWEVER, what they're discovering is that calcium content of the lubricant is coating the combustion chambers and creating conditions for a build up and sudden "knock" events. This "low speed pre ignition".

The research into this area suggests that particular combinations, namely direct injection play a part in these seemingly sudden super knock events.

They've found that reducing calcium content in the motor oil helps to reduce it, but it seems that DI both helps to reduce knock and also predisposes the motor to it under certain, low speed, high load conditions. Obviously this phenomenon is made worse with poor fuel quality.

So things that help to mitigate the risk of these LSPI damaging events. Limit Calcium content of the oil. Run high quality fuel. Don't lug the motor (typical during highway passing conditions).

 

[shogun32]

Don't lug the motor (typical during highway passing conditions).

3000+ RPM for any large throttle application.

 

[RacerX#99]

jersey is definitely annoying for it. i pump my own gas at work at our municipal fuel station, it’s not like we hire people to sit out there and attend it for municipal vehicles…but i guess bc it’s government in nj it’s ok, but the public, god forbid they do it!!! ridiculous lol. and i’m sure i will try using 91 once i stop wasting so much gas driving around daily all over just bc she’s brand new lol

Let me explain something about pumping your own gas. I lived in NJ for all of 65 years and I always pumped my own gas in my CJ Mustangs in the '60s because I was a regular and knew the owners. When I went outside my area I got out and watched the gas jockey pump in my cars that they usually admired. Now I live in NC and almost all the gas stations are convenience stores so you can also buy your beer and lottery tickets while your car is sitting at the pump taking up space where somebody just like me just wants gas. If it's raining or 20 degrees get out and pump your own gas. Pumping your own is highly overrated. BTW I only use reg in my 2021 GT

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