Does anyone know of any stations around Columbia (Forest Acres) that still have Ethanol free 90 octane? All of my spots have recently changed from 90 octane to 87.
Does anyone know of any stations around Columbia (Forest Acres) that still have Ethanol free 90 octane? All of my spots have recently changed from 90 octane to 87.
I would use 87 and add some 93 to it
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The station on Longtown about a mile off Killian had it before. I'll check tomorrow and see if they still do or you can call them I guess,
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Download the Pure Gas app. I’ve found it to be pretty accurate. It’s showing that the Murphy express at beltline and two notch has it, as well as a couple others that aren’t too far.
Just curious, what are you running it in? I’m very particular about running ethanol free in my small engines, but honestly have never paid much attention to the octane level or found it to make a difference in my stuff.
Download the pure gas app.
I never even thought about 90 vs 87. Where does it make a difference?
Some of the newer four stroke outboards don't love 87 octane. It works but in my motor I have noticed a slight reduction in hp. Will check the pure gas app. The last few stations I have called said they had 90 but when I go there it js actually 87. The people answering the phones at the stations don't know what they really have usually.
There was an episode of Engine Masters (great show even if you're not a gearhead) where they tested the effects of octane in an engine on a dynamometer. They found no difference in horsepower or consumption rate. They determined that as long as your engine doesn't knock (pre-ignition), there was no tangible benefit to going higher.
Shell on the corner or forest and Trenholm has it. There is also a little Indian joint over on two notch that has it.
Citgo on leesburg rd has it too.
Interesting. My golf cart post-ignites like a mother. Would premium gas help with that?
Post ignition (backfiring) is most likely too rich mixture.
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They tested car motors or boat motors? The Shell at Forest/Trenholm just changed from 90 octane to 87.
Car engines but the physic would be similar to a 4 stroke boat engine. Your mileage my vary. Not trying to talk you into anything.
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It's not mixed.
That may be true if the engine is designed to require nothing above 87.
Compression ratio, or more specifically cylinder pressure, determines octane. Higher performance engines require higher octane fuel to make the most power. Optimal ignition timing is a balance between Crank angle mass fraction burn and the rate of heat released into the combustion surfaces.
If you run 87 in an engine requiring 93, the 87 will have less resistance to igniting, therefore the knock sensors will detect the detonation(knock) and will retard ignition timing. Ignition timing affects cylinder pressure greatly. Optimal timing is around 10° after tdc to make the best power. If you can’t advance timing without inducing knock on 87 octane, higher octane is your easy solution to produce max torque/power.
That is why for example, the vmax sho 4.2L block is 87 for the 200 but the 225 and 250 requires higher octane. The same engine can be tuned to make 200 or 250hp, mainly by increasing timing, but at a compromise of needing higher octane.
If the gas cap says premium recommended, it is designed at the factory to run higher octane. If you run lower octane the engine will retard timing when knock is detected. You probably will never notice unless you are driving in the mountains or towing because that is when cylinder pressures and cylinder wall temps are highest.
Murphy Express, that new joint on the corner of Two Notch and Beltline has 90 at every pump.
33ABBA87-A6B8-481E-8EFC-60B2BA12EFC9.jpg
So you're saying, if I'm reading this right, that my 2000 Land Cruiser V8 engine, that the manual says should be drinking 91/93 octane pure gas, but has been getting 89/90 pure gas or E10 for 179K miles, could have been run on 87 E10 all those years, except when I was going to pull a trailer or head to the mountains?
If so, there's a pile of $$$'s wasted... although I'm assuming that the mpg would drop, just like I see a 10-15% drop in mpg with E10 vs Pure gas (89/90 octane).
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The shell on leesburg just dropped their 87 e free so I am told. The new Citgo almost just across the street has the 90 efree selling cheaper than the shell previously mentioned.
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