87+ Octane Gas vs. 91+ - HELP

[M&M Beer]

I run the cheapest gas I can find in my bronco the only reason i would run 91-93 would be if I were going to let the gas set in the tank for a long period of time. Iook at the owners manual and you can use 87 all the time.

Sponsored

 

[brkdncr]

Modern engines sense "knock" and can adjust timing (when the valves open/close/spark etc...)

timing is not when the valves open/close.

timing is simply when spark happens in relation to where the crankshaft is at. It’s measured in degrees before top dead center of a piston, which is a static location of the crankshaft

in old cars timing was tied to the crankshaft by gearing, typically off the camshaft, through the distributor.

as engines progressed, valves became variable and timing became more important. The crankshaft position sensor now communicates the location of the crankshaft to the module that controls spark, replacing the old distributor with its inherent inaccuracy.

now days engines have valves that open effectively whenever they want. Spark can also occur whenever, but it’s still directly related to crankshaft position.

 

[5GENIDN]

timing is not when the valves open/close.

timing is simply when spark happens in relation to where the crankshaft is at. It’s measured in degrees before top dead center of a piston, which is a static location of the crankshaft

in old cars timing was tied to the crankshaft by gearing, typically off the camshaft, through the distributor.

as engines progressed, valves became variable and timing became more important. The crankshaft position sensor now communicates the location of the crankshaft to the module that controls spark, replacing the old distributor with its inherent inaccuracy.

now days engines have valves that open effectively whenever they want. Spark can also occur whenever, but it’s still directly related to crankshaft position.

Well see... I said someone would be able to describe what is happening better than I could....

I agree it is not changing "when the valves open or close" but in changing the ignition point relative to when valves open or close.... You described that more acuratly than I did.

 

[jzweedyk]

Maybe I have bought into the "hype", but my understanding is that the premium gas has more additives than regular. IF that is true (I did not work in the energy department), then higher octane is "better" than lower octane, not just different. I also believe in the top tier designation and for the most part only use that.

The other thing I don't get is that you are willing to change you oil way before it is called for, but not willing to put higher octane gas in the tank.

 

[PolarVortex]

Maybe I have bought into the "hype", but my understanding is that the premium gas has more additives than regular. IF that is true (I did not work in the energy department), then higher octane is "better" than lower octane, not just different. I also believe in the top tier designation and for the most part only use that.

The other thing I don't get is that you are willing to change you oil way before it is called for, but not willing to put higher octane gas in the tank.

No - the additives are pretty much the same if you get 87 vs. 93 and anything in between if you go to a Top Tier station. "Regular", "Mid-grade", "Premium", "Ultra" etc all denote octane names.

 

[jzweedyk]

Thanks for the input.

I still stand by my "better" comment regarding 91/93 vs 87. If it gives you more horsepower and slightly better fuel mileage (documented several times over on the F150 Raptor forum, by several studies) then I would call that better. If you don't want "better" use 87 and you will be fine.

 

[PolarVortex]

Yes then I would agree with you that it's better, in however you like to reference the word. No matter what, I'm with you that our Broncos like the higher octane.

 

[AZ_Liberty]

This is why I will always run "Top Tier" gasoline no matter what Octane I use.

I think I would have to work pretty hard to find a gas station that was not part of the "Top Tier" org.

Even cheap places like ARCO or Quick Trip are part of the Top Tier consortium.

 

[AZ_Liberty]

I run the cheapest gas I can find in my bronco the only reason i would run 91-93 would be if I were going to let the gas set in the tank for a long period of time. Iook at the owners manual and you can use 87 all the time.

That would only make a difference if the 91-93 was actually 100% gas and not 10% ethanol. Some places that's true. Here, all the gas at all grades is 10% corn squeezins.

 

[5GENIDN]

I think I would have to work pretty hard to find a gas station that was not part of the "Top Tier" org.

Even cheap places like ARCO or Quick Trip are part of the Top Tier consortium.

There are a lot of places around my neck of the woods that sell gas at a discount. I do not trust them to be adding the detergents at the prices they are offering. I may be wrong.

There are always lines of cars looking to fill up at them though.

 

[BigHoof]

I think I would have to work pretty hard to find a gas station that was not part of the "Top Tier" org.

Even cheap places like ARCO or Quick Trip are part of the Top Tier consortium.

Not here. Sheetz, and GetGo have pretty much taken over along with a sprinkling of Speedways. None are Top Tier. Belong to Costco but it is 45 minutes away so not going there for fuel unless I'm there shopping.

 

[AZ_Liberty]

There are a lot of places around my neck of the woods that sell gas at a discount. I do not trust them to be adding the detergents at the prices they are offering. I may be wrong.

There are always lines of cars looking to fill up at them though.

Admitedly I am in a large metro area. If I road trip, the cheapest places are almost always the major truck stops (Loves, Flying-J, Pilot).

The East coast has a bunch of stations I have never heard of before. I was in Detroit on a business trip last week, and didn't recognize a single brand.

 

[5GENIDN]

Admitedly I am in a large metro area. If I road trip, the cheapest places are almost always the major truck stops (Loves, Flying-J, Pilot).

The East coast has a bunch of stations I have never heard of before. I was in Detroit on a business trip last week, and didn't recognize a single brand.

Truck stops are great! I just always look to see what brand of gasoline they are offering. One flying J may offer one brand and another a different brand. Although, to be honest... doesn't Flying J offer there own branded gas???? I know they do not produce it but I do not know what they are offering if it is rebranded.

 

[Roofus]

This is the dumbest advice I’ve ever heard for a turbo engine. Find a new tech. You actually risk getting “ping” from lower octane fuels not burning efficiently in a turbo motor.

 

[KirchTX]

Great writeup Joe.

FWIW, here in VA we have Sunoco (a Top Tier) which has four choices of octane - 87, 89, 91, and 93. I just got my Bronco and it's got the 2.7 which I love. The free tank of gas from the dealership was nothing special and it didn't feel right to me, like the Bronco was holding back slightly. The engine sounded just, ok, but no loud knocks or anything. So I put 93 in it when I got it as empty as I could, comfortably. Since then I've noticed a slight improvement in the acceleration and general performance and the engine sounds better. I agree it's not a good idea to jump from one octane to another too much so I won't do that, but I may try a tank of 89 or 91 just once in a while to compare.

In the meantime, the price difference works about to be about $5.50 a fillup more with 93 than 87. I worked out that it's around $265 per year more to use 93 over going with 87 at today's price by me, with my commute and number of fillups (about once a week).

At the moment, I'll stick with 93 whether it's a placebo effect or not, as that seems like an ok trade-off to me.

Shouldn’t you go with the 91 since that’s what Ford says the engine is tuned for? Or is there additional benefit between 91 & 93?

I’ve never seen 91 & 93 sold together unless it was 0% ethanol and then it has a different octane.

Sponsored