"Treating" your car with 93 octane gas

[Thirdgen89GTA]

Some of my family members do this. Their car specs 87-93 octane, but they normally run 87.

They occasionally "treat" their car with 93 octane at the pump. And every single time they mention it, I tell them that if the car was designed for 87 octane, then 93 won't do a thing for it.

But they don't seem to understand it. If your car is rated for 87, just run 87 unless you like paying more at the pump. As long as its good gas 87 vs 93 isn't going to net any benefits in most cars.

I only know of a few cars that seem to have timing tables aggressive enough to take advantage of 93 octane when the fuel door says 87+. The Focus ST happily runs on 87 octane, but with about 10hp less than its 252hp rating according to Ford. I never ran anything but 93 in it.

Click to read more...

 

[blck10th]

If the car doesn't need it. I don't run it. I have a dd that only needs 87 and I've never put anything higher in it. And I won't.

 

[MikeyLikesIt]

87 in the minivan that only requires 87. 93 in the Acura that recommends 93.

 

[P40E]

It is a noticeable difference in my fiesta se . I use 89 .

 

[Thirdgen89GTA]

It is a noticeable difference in my fiesta se . I use 89 .

I think Ford is calibrating the cars to run on 93 octane, and giving enough leeway in the tune that it will back the timing off. I know they do it on the "ST" line.

 

[10sec]

IDK man, the reason it "backs if off" is because it's seeing knock. I think that's why most cars gain so much from just a tune, as the tune is set to the lowest octane rating to keep dumbass car owners from blowing the cars up whilst not paying attention to what fuel is needed.

 

[sickmint79]

it probably really comes in handy when they never go above 4000 rpm too

 

[Thirdgen89GTA]

IDK man, the reason it "backs if off" is because it's seeing knock. I think that's why most cars gain so much from just a tune, as the tune is set to the lowest octane rating to keep dumbass car owners from blowing the cars up whilst not paying attention to what fuel is needed.

Pulled from the Focus ST supplement.
http://www.fordservicecontent.com/Ford_Content/catalog/owner_guides/13focst1e.pdf

252 hp @ 5500 rpm on 93 octane 243 hp @ 5500 rpm on 87 octane
270 lb-ft @ 2500 rpm on 93 octane 270 lb-ft @ 2500 rpm on 87 octane

* SAE Certified Performance ratings are achieved with 19.5 psi, but up to 21 psi can be delivered to maximize power depending on fuel quality and atmospheric conditions

OCTANE RECOMMENDATIONS
Regular unleaded gasoline with a pump (R+M)/2 octane rating of 87 is recommended. Some stations offer fuels posted as Regular with an octane rating below 87, particularly in high altitude areas. Fuels with octane levels below 87 are not recommended. Premium fuel with an octane rating of 93 or higher will provide improved performance and is recommended for severe duty or high performance usage.

 

[jason05gt]

My wife's Edge Sport feels noticeably different when running 93 vs 87. MT recently did a test to verify this.

 

[Thirdgen89GTA]

My wife's Edge Sport feels noticeably different when running 93 vs 87. MT recently did a test to verify this.

Maybe its the newer cars that have more learning ability in the PCMs.

Speaking more for the early and mid 200x's with my initial post.

 

[Bruce Jibboo]

I think a lot of luxury car owners put in premium because premium

granted these days many are designed for the higher octane with the forced induction on so many motors.

 

[IDAFC21]

I envy people that only have to put 87 in thier cars.

 

[Bruce Jibboo]

Although I noticed the John Deere and other small motors seems peppier on 93 so now all the lawn equipt gets 93. Could be a false sense though lol.

 

[sickmint79]

 

[Bob Kazamakis]

I tried premium in my truck for a tank. Felt the same. Now it's back to the swill that is 85 octane.

 

[Stink Star]

My last several cars require premium. Otherwise it's regular

 

[firemandan1700]

On the TCG Tour last year, for shits I ran about 3 tanks of 93 through the 1978 vette and it actually ran worse.

 

[Primalzer]

93 octane actually is marginally less power dense than 87. It resists ping better, what the octane rating means, but it actually contains less power per unit than 87. If your car can take advantage of 93, it'll run better, get better fuel economy, make more power, etc. But if your car doesn't specifically have tables for 93, it'll theoretically run worse than 87.

 

[Bruce Jibboo]

93 octane actually is marginally less power dense than 87. It resists ping better, what the octane rating means, but it actually contains less power per unit than 87. If your car can take advantage of 93, it'll run better, get better fuel economy, make more power, etc. But if your car doesn't specifically have tables for 93, it'll theoretically run worse than 87.

100%, sluggish enough for some cars to end up at the dealer asking whats wrong after putting in 87 when 92-93 required.

 

[Fish]

IIRC running higher octane than needed makes the engine work harder to ignite the fuel. If that is correct, good job making your engine work harder. Treat yourself.

 

[Primalzer]

IIRC running higher octane than needed makes the engine work harder to ignite the fuel. If that is correct, good job making your engine work harder. Treat yourself.

This is true...93 has less power per unit, than 87

 

[Chet Donnelly]

I can tell a difference in my Explorer between 87 and 93. The PCM has to be adapting to the fuel in it.

I've even tested this (not super scientific) by doing a few pulls against a buddy with the same exact Explorer and he runs 87 (both have 3.5L twin turbo V6). I can slowly pull away from him.

 

[Primalzer]

The Ford EcoBoost motors will run on 87, but will run stronger on 93. That's a known fact. The same goes with their Coyote's in the Mustang. I'm not sure about the Coyote's in the F-150 though.

 

[Bruce Jibboo]

nothing like a little knock and a little knock retard and fuel trim adjustments to stick it to the man

 

[Primalzer]

All the turbo motors I've had, I never ran anything below 91 (only ran 91 when 93 wasn't available.) To me, it wasn't worth the possibility of detonation and engine failure.

I will run E85 through my flex fuel vehicles every 6 months or so. My theory being that the corrosive-ness of the ethanol will theoretically keep the fuel system clean, and the ethanol will bind with and eliminate any excess moisture. I take the hit in fuel economy for that one tank (usually 20-30% fewer MPG's.)