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Just about any modern ECU can adjust to running different octane fuels, and for regular driving, it's not going to harm anything.
Now if its a turbocharged car, or any type of forced induction, the higher octane is necessary... unless you stay out of the throttle and baby the car and never use the turbo.
No car comes from the factory requiring 93. It's 91, because that's the highest that is sold in some markets. The difference between 91 and 89 is very slight, it isn't going to harm anything.
You don't know a lot about reading, huh?
What I said is that a manual adjustment is not easily done. The average Joe would not have the wherewithal to reprogram an ECU to retard the timing away from the factory spec. It's not exactly like turning the distributor a degree or two. It also doesn't 'fix' anything as the issue is pre-ignition due to compression rather than engine timing.
Also, they said they only had 93 available. Hence, I said "go with the 93." I'm quite aware of the fact that the requirement for the vehicle is 91. You see, unlike you, I actually read what they said.
The cost difference between 89 and 93 is what is very slight (generally a dime or two per gallon). If the ECU is modern enough to be able to detect the inevitable pre-ignition that running 89 will cause (especially when the hammer is down), that dime a gallon will be money well spent as the ECU will adjust at the expense of power and economy (at best - again, it's a compression issue). If the ECU is not so equipped, enjoy the new engine you will be buying in 6-12 months. Either way, their is nothing the ECU can do to change the inherent compression ratio of the engine. What it can do is retard the timing and increase the fuel to air ratio (just as it does upon acceleration) thereby reducing the internal temperature of the cylinder and making pre-ignition less likely to occur.
But, no, I don't know a thing about cars... OR chemistry, OR controls, for that matter.
The bottom line is that if the vehicle's manual mandates 91 octane as a minimum, you should use it. If it provides a range of 87-93 with 91 being recommended, use whatever you want. However, a higher octane fuel in such a vehicle will provide increased performance as well as increased fuel economy. At a max expenditure of $100 per 500 gallons, there is no reason not to use the proper fuel.
Last edited by Cleveland_Collector; 08-29-2014 at 08:09 AM..
Except that he's wrong. In the US, we use the R+M/2 or AKI. In general, that translates to RON - 4 (the difference between RON and MON is usually 8). So, a 95 "octane" rating in Europe is actually 91 in the US (95-87/2).
I pity the fool who heeds your advice. You epitomize the handyman mentality.
No, I simply know that you have no idea what you're talking about, no matter how many revisions you make to your posts with newfound google "knowledge."
Quote:
Originally Posted by Cleveland_Collector
It has nothing to do with and cannot be 'fixed' by retarding the timing (as if that was even a simple thing to do anymore). If you don't run the proper fuel, you run the risk of damaging the engine.
So there you said that retarding the timing isn't a simple thing to do (it is, the ECU does it for you, genius.)
Quote:
Originally Posted by Cleveland_Collector
What I said is that a manual adjustment is not easily done. The average Joe would not have the wherewithal to reprogram an ECU to retard the timing away from the factory spec. It's not exactly like turning the distributor a degree or two. It also doesn't 'fix' anything as the issue is pre-ignition due to compression rather than engine timing.
Here it's clear you don't know a damn thing about timing, and you don't know the difference between engine timing and ignition timing. The "average Joe" has to know how to reprogram an ECU to retard timing? Pre-ignition is caused by HEAT, not compression. You also didn't say anything about a manual adjustment. LOL
Quote:
Originally Posted by Cleveland_Collector
If the ECU is modern enough to be able to detect the inevitable pre-ignition that running 89 will cause
Oh look, here you are now admitting that the modern ECU can adjust for 89. That's about every car manufactured from the early 90's to now.
Quote:
Originally Posted by Cleveland_Collector
The bottom line is that if the vehicle's manual mandates 91 octane as a minimum, you should use it. If it provides a range of 87-93 with 91 being recommended, use whatever you want. However, a higher octane fuel in such a vehicle will provide increased performance as well as increased fuel economy.
Ah, and then you follow up with this bit of idiocy here. You think that running a higher octane blend will give you increased fuel economy? LMAO
I repeat, you have no frickin clue what you're talking about.
For the record, I've run just about every fuel there is. Pump gas, race gas, ethyl/toulene mixes, meth injection, and E85. I've swapped injectors, tuned ECUs, and run them all successfully.
You keep up with your googling, though. It's impressive.
Except that he's wrong. In the US, we use the R+M/2 or AKI. In general, that translates to RON - 4 (the difference between RON and MON is usually 8). So, a 95 "octane" rating in Europe is actually 91 in the US (95-87/2).
Interesting, because as I started to read this thread I looked up that standard unleaded over here is 95 RON and premium is 98 RON.
Except that he's wrong. In the US, we use the R+M/2 or AKI. In general, that translates to RON - 4 (the difference between RON and MON is usually 8). So, a 95 "octane" rating in Europe is actually 91 in the US (95-87/2).
He posted a pic with 93 RON. That makes it 89 octane.
Do you really want to continue to make yourself look foolish? It's still pretty early.
Where down south? I see it everywhere between here and Mobile, AL. Either way, 93 is fine. 91 is the minimum. Sometimes you will get some detonation if you use a lower than recommended octane.
Mississippi
Quote:
Originally Posted by brianjb
Get the 93 octane. You're only talking a 10 cent difference in price between that and the other, right?
89, $3.30 and 93, $3.47. 17 cent difference
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