100 Octane Fuel
#82
Three Wheelin'
huge disadvantage in fuel economy, as more fuel is needed per unit air to get the correct afr to run the engine in comparison with gasoline. This translates to a lower heating value for E85 than gasoline.
so save ur corn lol
#85
I have yet to notice any pinging at 91 octane. I would be surprised if anyone here has pinging at 91 octane assuming a properly tuned and clean engine. Acura might be octane greedy, but they aren't stupid, and they know what premium gas is in the country the car was designed for. If you're pinging at 91, you might have carbon buildup in the cylinders, which, by the way, can be caused by running gas with a too-high octane rating. If the fuel doesn't completely burn in the power stroke, you end up depositing unburned bits of carbon on the cylinders. Once you get enough carbon buildup, it retains heat from the fuel burns - enough heat to cause the fuel/air mix to explode prematurely, which causes the pinging.
I'd be interested to see the opinion of an actual Acura engineer here, because it wouldn't surprise me at all if the guys running 100 octane or 97 octane mixes are actually messing up their engines.
#86
Three Wheelin'
The gain comes from the ECU no longer retarding the ignition timing so much. The fuel itself, as you have pointed out, doesn't add any power whatsoever.
I have yet to notice any pinging at 91 octane. I would be surprised if anyone here has pinging at 91 octane assuming a properly tuned and clean engine. Acura might be octane greedy, but they aren't stupid, and they know what premium gas is in the country the car was designed for. If you're pinging at 91, you might have carbon buildup in the cylinders, which, by the way, can be caused by running gas with a too-high octane rating. If the fuel doesn't completely burn in the power stroke, you end up depositing unburned bits of carbon on the cylinders. Once you get enough carbon buildup, it retains heat from the fuel burns - enough heat to cause the fuel/air mix to explode prematurely, which causes the pinging.
I'd be interested to see the opinion of an actual Acura engineer here, because it wouldn't surprise me at all if the guys running 100 octane or 97 octane mixes are actually messing up their engines.
I have yet to notice any pinging at 91 octane. I would be surprised if anyone here has pinging at 91 octane assuming a properly tuned and clean engine. Acura might be octane greedy, but they aren't stupid, and they know what premium gas is in the country the car was designed for. If you're pinging at 91, you might have carbon buildup in the cylinders, which, by the way, can be caused by running gas with a too-high octane rating. If the fuel doesn't completely burn in the power stroke, you end up depositing unburned bits of carbon on the cylinders. Once you get enough carbon buildup, it retains heat from the fuel burns - enough heat to cause the fuel/air mix to explode prematurely, which causes the pinging.
I'd be interested to see the opinion of an actual Acura engineer here, because it wouldn't surprise me at all if the guys running 100 octane or 97 octane mixes are actually messing up their engines.
Just so you know, the motor runs completely lean while in closed loop, and below 3000-3200 rpm, and on any given hot day, ECU will pull enough timing to make the car pretty sluggish.....what everyone is talking about here is that running higher octane, will stop the ECU from pulling timing, therefore you will end up with its full potential...they're not trying to make additional power by running higher octane.
and by the way, higher octane will BURN fairly well in 11.0:1 compression, with proper spark.
they dont have any exessive levels of carbon build up...they dont even run higher octane fuel...theyre just talking about the differences it would make.
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