Running 89 octane

[gbub]

Static compression ratio is fixed but dynamic compression ratio is not. Valve timing can change dynamic compression ratio and turbo boost does too.

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[swamp2]

But Top Tier 87 > grocery store 89 (or even 93).

Similarly, and in contrast to your prior post, Costco isn't good gas, they use so many suppliers and what you get isn't the same each time, nor does it have a consistent additive package. I also think (no firm evidence) that no Costco gas has what is a top tier detergent package.

 

[adam1991]

Similarly, and in contrast to your prior post, Costco isn't good gas, they use so many suppliers and what you get isn't the same each time, nor does it have a consistent additive package. I also think (no firm evidence) that no Costco gas has what is a top tier detergent package.

where did you get your info?

Absolutely it has a consistent additive package. Every time. Because the do something that NO OTHER vendor does: they have a tank of their own Kirkland additive package on site, and it gets mixed in with every delivery.

This way, they can take from whatever vendors but ensure that what goes into the member's tank is top quality and Top Tier.

And it keeps costs down. Way down.

https://web.archive.org/web/2019012...DEF/Fuel Additives_Hurlocker_2013_Tuesday.pdf

It works just like the dosing at the terminal, when loading the truck, except smaller in scale. The truck delivers, and the dosing happens at that time.

For the record, it's Lubrizol 9888.

This process allows them to take ANY gas--including the tankers with the lowest legal dose of whatever lowest cost additive package (grocery store gas), but deliver to its customers a Top Tier gas. And at a cost lower than grocery store gas.

Again, where did you get YOUR info on how Costco runs their fueling program?

There's a guy here on the net somewhere, thinks he knows everything about the gasoline business because he used to run a group of stations many years ago. When I said that Costco delivers its own additive package at each delivery, he flat-out denied that that could possibly be--simply because "nobody does that" and he had never heard of it. He argued it to the death. Then he STFU after I pointed him to the link above.

On top of all that, Costco sells a metric shit ton of gas every day. Each station gets many deliveries each day. As a result, their gas is ultra fresh.

 

[Bugkillah]

Variable valve timing has no practical (theoretically, very very minimal) on the relationship between octane, knock, compression, etc. The significant mechanical factors are compression ratio (fixed), amount of turbo boost (controlled by computer at any given point), and timing advanced (where in the stroke cycle the spark plug is ignited, again controlled by the computer).

In other words, the reason the Ford Ecoboosts are somewhat "octane agnostic" is the computer's ability to vary boost and timing advanced based on what the knock sensors are reporting to it.

Corrected original post, thank you.

 

[zoober]

No reason not to run 87/89 on a regular basis if all your doing is driving around unloaded.
I do see quite a noticeable difference running highway speeds in the mountains, in terms of power. With 92/93 6th gear will climb anything at highways speeds with 800 lbs of gear. With 87/89 I’d have to drop to 5th or even 4th gear on the steeper climbs. No knocking whatsoever with either on the 2.3 L SAS MT. BTW, this is at 5000’+ ASL.

Was just in the Smokies this week. Going up to Kuwohi (Clingmans Dome)at 6600 ft, I had no issues with 87.
I use 90% Shell gas. Only if I can’t find it do I use other gas.
I’ve run 93 a few times, and while I could feel (quite a bit) better pull, my mileage was the same-ish. I say ish because I don’t know if the conditions, foot, etc had anything to do with it.

 

[adam1991]

As long as we're discussing Top Tier gas:

 

[PlayTime]

Anyone running 89 octane in their 2.3l as your lower end fuel any issues or knocking I know the 2024 2.3 Ecoboost is rated for 87 octane but a few people on here seem to be having issues. 89 and 93 are regularly available here but if I can would like to run 89 all the time . Had a 04 Land rover years ago what a mistake thy was, it was 93 or nothing .

My personal experience is that I bounce between 91 and 87, depends on how I feel that month. '23 OBX 2.3L automatic
There's a minor difference with 91, but 87/89 has never pinged, or failed passing on the freeway or canyon here.

 

[Bronc69]

I run Top Tier 87 in my 2.7 all the time. Zero issues. TBH, it's not the octane that's the issue, it's the additives that keep your engine running cleaner. I've run Top Tier fuels in all my cars since I found out about them. I keep cars a LONG time and have had zero fueling issues with any of my cars (2000 VW Golf GL for 15 years with 240K miles).

For me, it's not a "high performance" machine. It accelerates without any issues regardless of octane. I drove it in Sport mode once and scared me LOL! It just doesn't make sense to me to have an overly reactive throttle and transmission mapping when the vehicle is more suitable for off-roading. But, that's me.
It can get me out of a bind if I need and cruises nicely. What more do I need? For me, the higher octane is a waste of money.

I'll run 94 in my 911 that has a tune and makes over 500hp.

 

[WildBill44]

Has anyone tried any additives to help keep the valves from building up gunk. I have seen a lot of videos showing the 2.3 Ecoboost with severe build up on the valves and Ford has no current answer for it so far no one recommends a safe alternative additive that won't hurt the turbo.

 

[adam1991]

Has anyone tried any additives to help keep the valves from building up gunk. I have seen a lot of videos showing the 2.3 Ecoboost with severe build up on the valves and Ford has no current answer for it so far no one recommends a safe alternative additive that won't hurt the turbo.

No additive will help. Fuel doesn't wash over the backs of valves in the 2021-2024 2.3. So, they never get cleaned off.

Some swear by Seafoam treatments. That's up to you.

 

[chern03]

Anyone running 89 octane in their 2.3l as your lower end fuel any issues or knocking I know the 2024 2.3 Ecoboost is rated for 87 octane but a few people on here seem to be having issues. 89 and 93 are regularly available here but if I can would like to run 89 all the time . Had a 04 Land rover years ago what a mistake thy was, it was 93 or nothing .

 

[chern03]

Anyone running 89 octane in their 2.3l as your lower end fuel any issues or knocking I know the 2024 2.3 Ecoboost is rated for 87 octane but a few people on here seem to be having issues. 89 and 93 are regularly available here but if I can would like to run 89 all the time . Had a 04 Land rover years ago what a mistake thy was, it was 93 or nothing .

I have a 2024 Bronco Black Diamond I purchased in Oct, 2024. Somewhere along the line, I heard the engine is computerized to settle into adjusting to the octane level commonly used/purchased. I tried a few monitoring my mpg per tank.
Costco 87 Octane won. I was getting over 20mpg at first, but quickly settled down to 18, sometimes 16-17 on snow days with 4-wheel drive on.
In Feb, 2025, I found Costco 87 to run the best and consistently.
I am getting 20mpg now with Costco gas.
I just drove to Utah round trip from SE MI. I found Costco gas on my route even up to Salt Lake City.
I got HWY 20mpg.
I got mixed 20mpg at home around town.
(I went into the dealership for warranty service and received my car at 19.2, go figure!)
Now, I had a 2013 Ford Taurus. I had low gas milage with Costco gas, but had 28-32 mpg.
Oh the days of a good old sedan!

 

[Brian_B]

Somewhere along the line, I heard the engine is computerized to settle into adjusting to the octane level commonly used/purchased.

Sorta.

It will dynamically adjust according to knock, and knock is directly related to what octane your fuel is. This adjustment happens very quickly - several times a second. And it's very sensitive to knock - it can pick up events before it becomes something you would hear as pinging.

But, it has to have a starting point when you first start the engine - it has no idea what the octane really is, so it does have a parameter called Learned Knock Modifier that adjusts over time. But it only affects the timing when you first start up, the dynamic adjustments always override it. But if they are always overriding in one direction, the computer will bump the Learned Knock Modifier in that direction so it starts closer to what gas you are using.

It does take several miles - some say upwards of a full tank, for Learned Knock Modifier to settle in if you change octane. Tuners use this to determine if you still have room for additional adjustment, or if you need to adjust the mix of your fuel.

 

[Zeaks]

Where? It's gotten stupid around here--a buck more. I'd die if I saw a 40 cent differential anymore.

Costco in Georgetown, TX. The other Costcos around me are sometimes less, same, or more. I just looked and 93 is 3.07 and 87 is 2.49, so 0.58 cents more currently. A month or two ago I was getting 93 for 2.90-2.95 and 87 was still around 2.49. I generally only fill up once every two weeks so the extra $20-$30 a month is not an issue for me.

 

[adam1991]

so 0.58 cents more

be careful with throwing phrases like that around. 0.58 cents is just a tad over half a penny. Fifty-eight hundredths of a cent.

You mean 58 cents, or 0.58 dollars (also expressed as $0.58).

Verizon learned that the hard way:

https://verizonmath.blogspot.com/2006/12/verizon-doesnt-know-dollars-from-cents.html

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