87 Octane Ethanol Free or 90 Octane Ethanol Free??
Not about the dollars, all about the numbers. Gotta get those MPG numbers up.
I'm driving a 2000 Insight with LTO conversion. So Ethanol Free >> Ethanol for the MPG numbers, but which octane should I be buying? Some gas stations near me have 90 others have 87. On my fuel log I track the gas type used. That's the 2020 log, you can find my older log (Pre-Lithium) in there as well. |
In theory if you can find non-oxygenated ethanol free in a lower octane it should give the best fuel economy. (I’ve only seen it in MN)
Historically there were some comments that the Insight required higher octane overseas but generally 87 has more energy content. Not sure which would win out, I guess if money is no object throw in some 0w16 oil and dose the tank with some MMO and run a separate tank of each. I’m leaning toward 90 winning but only by a hair Will be interesting to see your results. |
I have 0W-16 in the engine, what is MMO?
It's hard to get conclusive fuel tank results because of factors like weather and traffic. My tanks vary greatly. Random things like, did I forget to activate my clutch switch on the high way (to keep it from regening in lean burn if the SoC gets low) a couple times, have very large effects. |
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To my knowledge 90 should not make any more power unless the ECU can specifically detect it and adjust ignition timing for it.
Typically engines with high compression can have knock when above ~80% load, and the Insight has pretty high compression. It also has a knock sensor. If the sensor detects knock, it'll pull a few degrees of timing, which affects both power and fuel economy. I believe any knock detected also throws a CEL but I'm not certain if there's a threshold (above zero) for that. But, typically, an engine will not knock on the octane it's rated to have, and if it's not knocking, and the ECU isn't pulling timing to get rid of the knock, higher octane shouldn't help economy because it only really provides more resistance to knock. |
How is the LTO conversion?
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with 87 i barely get 18.5/18.5 91 octane 23/31.2mpg it's able to pull a tight timing of upto 42 degrees advancement with it it's normally around 27-35 degrees on average with 87 oct 12.5 degrees advancement is where it tops out at retards the timing in AFM mode to about -2 to -12 degrees it would also rapid flip flop between v8 and v4 (sure that can;t be good for the engine) it's more likely to search for gears with 87 octane |
Variable Valve Timing (VVT) is not ignition timing (spark plug timing). VVT would not indicate an engine's ability to benefit from higher octane, and would not allow changing any variables affected by higher octane.
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Octane (number) is only relevant to compression ratio. (Pre ignition) The additive package is what’s really relative to any performance gains. Go to a race track or airfield and buy gas. (110 octane race gas or 130 avgas) Currently (approximately) around $4-6 per gal. You’ll see what real gas can do...;) When I was young and spilled some gas you dare not light a cigarette or create a spark unless you didn’t care about your eyebrows. Now you almost have to hold the flame to it to make it burn. How things have changed. :( Petroleum Companies figured out how to extract the chemical compounds in consumer grade fuel for other products (more profit) while leaving the bare amount necessary for ignition in a internal combustion engine. There is a silver lining with today’s E85 though. One can build a high hp , high compression engine (15 to 1) to easily take advantage of the high Octane number (108) . Research where your fuel comes from. As there can be noticeable differences. Brand names usually have their own storage tanks (additives) that they pull from but not always. No name gas stations usually get whatever is available through the bulk distributor. (Crap shoot) Seriously, try some race or avgas and let us know what happens. :) > |
Hate to tell you this but AVGAS is heavily leaded, will clog a cat in one tankfull. Probably the same for race gas, but I'm otherwise qualified.
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I forgot about that...:o My bad... https://i.postimg.cc/ZRCtX1YP/BD5617...F60-D607-B.gif > |
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In fact diesel increases economy In part due to more BTUs If the op is truly only going for only max fuel economy she could do this https://ecomodder.com/forum/showthre...ine-11163.html If that is done I would recommend mixing it with the 90efree, because modern diesel is lower sulphur than gas the emissions are lower as well. Again would be an interesting experiment |
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i.e 87 is 2.599 gallon while 89 and 91 is 2.799/2.899 summer fuel normally nets 2-3mpg more then winter fuel.. example Costs; (city/highway) 2.599 18.5MPG 0.1404864864864865/miles 91octane 23mpg city 2.899 0.1260434782608696 27-31.2MPG 0.107 to 0.092 per mile. would you rather pay more up front OR pay more per mile? using 87 octane cost $3.22 per 23 miles in the city per gallon using 87 octane costs 3.78-4.36 on the highway per gallon 18.5 is the confirmed mpg which others get with "87 octane" |
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I forgot about them containing lead... Come to find out they make unleaded race fuel... https://www.sunocoracefuels.com/fuels This particular one has a high btu. value. https://www.sunocoracefuels.com/fuel/optima Adding diesel fuel to gasoline will lower the octane number possibly below which the PCM is able to adjust timing for thus decreasing efficiency and increasing pollutants. Like I said it has everything to do with the additive package. Shell makes a premium gasoline that is sold at the pump called “V power + nitro” that contains an advanced additive package. https://www.shell.us/motorist/shell-...-gasoline.html I would try the Shell V-power + Nitro. It’s the least expensive and easiest to purchase. :turtle: > |
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that is why i fill up only at Chevron or Mobil stations |
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87e10 -$0.95 87e0 - $1.25 88e15- $0.92 91e10- $1.65 I don’t think the op is worried about cost, Also the thread pointed to someone who used diesel in his gasoline truck for many years without issue besides higher fuel economy Generally smaller amounts of modern diesel in gas will not have any detectable affect on emissions . In the 80’s you could buy mileage master gas that had diesel mixed in right at the pump. |
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Additive packages Shell V-Power + Nitro - friction modifier and detergent https://www.shell.us/motorist/shell-...-gasoline.html TEXACO with Techron - detergents https://www.texaco.com/fuels BP with Invigorate® - detergents https://www.bp.com/en_us/united-stat...ces/fuels.html Sunoco with UltraTech™ - detergents https://www.sunoco.com/quality-fuels Top Tier Gasoline https://www.consumerreports.org/car-...h-extra-price/ These companies should be paying me... https://i.postimg.cc/ZRCtX1YP/BD5617...F60-D607-B.gif > |
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Techron is also available from Chevron Shell got sued anwhile back for false claims chris fix leaked out that they use 7x the additive in the premium fuel typically that is a closely guarded trade secret other wise it would get to the point were it's 100% fuel additive LOL |
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https://web.archive.org/web/20150111...and-myths.html |
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Any hydrocarbon mix is allowed in gasoline as long as it meets the octane rating, (biodiesel is not considered a hydrocarbon) that is why oil companies love ethanol because they can sell you your 84/85 octane kerosene mix with ethanol to boost its rating. Also many common injector cleaners are just diesel fuel in a can. An Insight isn’t exactly modern either (I have collector plates on mine) but it is efficient |
Anyone want to guess what the BTUs per gallon of Techron additive would be? I put two cans of it in my tank (40floz total) at the start of my last gas tank because of intermittent jerkiness at certain speeds and very intermittent (months between it lighting up) P0420 even though I have a (correct for this vehicle) new LAF sensor with less than 10k miles.
My most recent tank (even directly adding the Techron to the tank measuement as though it were exactly the same as 87 ethanol free gas) was my 2nd best ever. I filled with 90 Octane Ethanol Free this time around, we'll see what I get but I'm off to a good start with 90 on the FCD over the first 50 miles. |
IIRC a small-displacement engine tends to tollerate more a lower octane rating even with a comparatively higher compression ratio.
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Small engines tend to revolve faster so you are into the timing advance and flame front limitations to prevent knocking.
Techron could be doing so many modifications to the fuel, it is hard to say what is happening. Could have fuel thinners, octane enhancers, assorted solvents, who knows? Someone was touting the addition of 1oz acetone per tank as a surface tension modification. |
Thread is kind of old, but what's the purpose of this?
If you want maximum mpg just for bragging rights, you want the highest BTU/gallon mix that barely hits the octane requirement. That means mixing something high octane like toluene or paraxylene with diesel. ECUs are generally programmed to only use spark to compensate for knock, so you'll lose efficiency quickly if you drop much below the recommended octane rating. I don't think ethanol free 90 is going to beat 87 in terms of cost, but if you're going to add 90, you can mix in a tiny bit of diesel to bring the octane back down. Biodiesel harms cars because it has methanol, while normal diesel should be fine, I think. |
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What's the cost of E0 where you are? It's 70 cents per gallon higher than E10 here, so it's not worth it to me, unless I'm storing a car or other engine for weeks or months without using up all of the gas. I only saw 3/4 of a MPG better with E0 (90 octane) in my 05 Explorer, BTW.
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IIRC the only E0 gas available in my country is AvGas, but it's out of question due to the lead content.
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