I run 87 oct in my Fist and its fine :)

[HaveBlue83]

Just for anyone who always wanted to run crappy gas, i dont even notice a different btn 87 and 93. Ive been doing it for years. Used to run 93 when gas was cheap. I have exclusively used 87 unless i accidently pushed the wrong button since the admin change and gas went up.

Now, for all of you that say "ur gonna ruin your motor, your mpg will go down" blah blah.

I best this car daily, rev it all over, and i get an avg of 31.5mpg. 36.5mpg @65, 40mpg @55mph.

i have 173547 mi, and i did plugs about 120k. Front o2 sensor at 80k. That oil bucket thingy? Havent even LOOKED at it. No catch can. Stock tune.

Enjoy your bulletproof cars, guys n gals!

 

[TyphoonFiST]

Just for anyone who always wanted to run crappy gas, i dont even notice a different btn 87 and 93. Ive been doing it for years. Used to run 93 when gas was cheap. I have exclusively used 87 unless i accidently pushed the wrong button since the admin change and gas went up.

Now, for all of you that say "ur gonna ruin your motor, your mpg will go down" blah blah.

I best this car daily, rev it all over, and i get an avg of 31.5mpg. 36.5mpg @65, 40mpg @55mph.

i have 173547 mi, and i did plugs about 120k. Front o2 sensor at 80k. That oil bucket thingy? Havent even LOOKED at it. No catch can. Stock tune.

Enjoy your bulletproof cars, guys n gals!

Na....won't ruin the engine.But the car is smart enough with the OAR to take power down a notch or two when using regular gas*

Sent from my SM-S908U1 using Tapatalk

 

[HaveBlue83]

I didnt even notice a difference btn 87 and 93 with a cobb ots tune....hence why i put it back to stock.

Yeah, car iz smart. It adjusts so it always feels the same lol

 

[HardBoiledEgg]

WHO CARES

 

[SteveS]

There is truth here. The car runs just fine on regular unleaded. It may not reach the rated horsepower, but the amount of decrease makes no difference in day to day driving.

 

[FiestaSTdude]

I used 87 in mine for a while when I first got it and used it for door dash. Now I use 93 because I drive less. I definitely noticed a small decrease in performance with 87 but other than that, I've not had an issue with 87

 

[HaveBlue83]

WHO CARES

WOW GREAT POST. THANKS. 11/10


i got 173k miles, some people like to know how things hold up after years and miles more than they have. Im just reporting my findings. You can not reply if you dont like it lol.

 

[gtx3076]

I run E30 most of the year for years. Definitely a difference felt between ethanol and 93. I can only imagine how stark that would fee between 87 stock tune and E30.

 

[Mikey456]

I think it’s fine on a stock tune because it adjusts for the lower octane like the other ecoboost motors. The engine runs hotter when you run the tunes that are designed for 91 oct and above and run over boost all the time.

 

[DEss]

I run E30 most of the year for years. Definitely a difference felt between ethanol and 93. I can only imagine how stark that would fee between 87 stock tune and E30.

It's pretty apparent. I usually go 87 but if I'm near empty and near a station with e85, I run my e30 because the cost with 3+ gals of e85 and rest in 93 is very comparable to topping off in 87. Anyway, with the 87 stock tune it almost feels like an NA. It's a pretty gradual build up. With e30, there's a definite kick-in- the-ass feel as the rpm build - like the old 80s-90s turbos.

DS

 

[M-Sport fan]

^^^E85 is readily available in BROIKLINN??

 

[DEss]

Not readily...was one Citgo with it in Starret City. Another place in Queens had it. And then, a few in LI.

DS

 

[Stkid93]

The way I see it is like this.

the computer will adjust timing and such but the problem with that mindset is that the computer needs to see knock in order to be able adjust for it. The computer can’t tell the future. And so every time the engine knocks. You are running the risk of damaging your motor. Maybe it’s small knock events. And 1 or 2 won’t do anything. Or maybe you get super knock, or have a really bad knock event that is big enough to damage the motor and the computer couldn’t save it because it couldn’t adjust until it was too late.

You are playing with fire to save $5 on your tank of gas. When running good gas, knock events may still happen, but they will be far less frequent, and the severity of the knock event will be way less intense due to the added octane. There are probably a million Subaru engines that have cracked ringlands and destroyed motors because of knock.

yes our ecus are far more advanced, but I just won’t risk it

 

[Intuit]

I'm not interested in less HP so have always run premium from new.
There are reasons I didn't go with the 2016 138HP Chevy Sonic RS.
The over-boost feature was one of them.

After running 87 for several tanks, don't expect full over-boost to be immediately available just because you decided to put in 93 this time.
When I step on the pedal I want that available. Full stop.

 

[CSM]

Perfectly safe to run 87 in the FiST. This has been discussed to death. The car will adjust the timing to compensate for the decrease in knock resistance, hence why it'll be down on power as well.

 

[WannabeST]

I think it’s funny how you’re running 87 in your ST but I’m running 91 in my SE to advance the timing just a few degrees. Car feels like the throttle response is slightly better but no power gain that’s noticeable.
(no hate, I just find it funny that we have different goals lol)

 

[HaveBlue83]

My old car is currently at 190k. Doing fine.

 

[NOVA_Ranger]

I run 87 in my '19 Ranger and I can't really tell the difference between 87 or a couple tanks of 93. Then again, I don't do much 'spirited' driving with my truck. I had a 93 performance tune on it for a while and WOW, that really woke the truck up (faster off the line than my Fiesta, even with the tune, for sure). For daily driving, 87 is fine in any vehicle that allows it.

 

[Stkid93]

I don’t know enough about it. But I’m just afraid that running 87 is fine until it’s not. And then you bend a rod or crack a cylinder because of a massive knock event. Will it happen it most situations? Probably not.

But you get a nice hot day, the engine gets real hot, and you get a knock event bad enough to do damage. Who knows. I just choose not to risk it. Am I wasting money on 93? Maybe. But the extra few dollars a tank is worth my peace of mind. I feel like on 87 I would be so worried about something happening that I wouldn’t enjoy driving the car, and would subconsciously baby it.

I think it really depends on the car, compression ratio, boost levels, how aggressive the tune is/what safety nets are built into the tune, heat range of spark plugs. heat/environment, and driving habits. So under most situations it will probably be fine. But when you’re running 27psi on a small 4 cylinder with tons of cylinder pressure. It starts to get scary.

 

[SteveS]

You won't have any damage running a stock Fiesta ST on 87 octane gas no matter what the temperature is out or how hard you drive. The car is made to handle it.

If you tune it beyond stock, then you are at your tuner's mercy. And if you're tuned, this thread is not for you. You have to then run the fuel that your tuner made the tune for. You have no idea if your tuner built in leeway for lower octane fuel or allowed the ECU to downtune itself to compensate (probably didn't). Even if you run the fuel it was tuned for you might then have trouble if they really pushed the tune.