I was searching around for some more info to answer "the great fj octane debate" when I came across this in on cartalk.com. Don't know if anyone else on the forum listens to their radio progam, but I've always found them to be both entertaining and pretty spot on. Anyway, here was there response to a similiar question on premium fuel use;
I recently bought a 1995 Infiniti J30t. It specifies to use only "premium" unleaded fuel. I'd like to experiment and see if I could safely save some money by using some portion of "less than premium" fuel along with the high-priced stuff. Can I do this without harming the car? And while I've got your attention, do you have a preference in gasoline brands? -- Conrad
Ray: Well, Conrad, we don't have a preference among gasoline brands for two reasons: 1. They're all basically the same, and 2. None of them has offered us a huge advertising contract to date.
Tom: And the answer to your question is no. I don't think you should use lower octane gas in this car over a long period of time. If you wanted a car that burned regular gasoline, you should have BOUGHT a car that burned regular gasoline.
Ray: Most modern cars have knock sensors, which detect pinging, which is often caused by the wrong grade of gas. When the engine pings, the computer retards the spark timing to compensate for the lower octane. That's designed to prevent engine damage if you get a bad tank of gas or travel someplace where the correct octane is unavailable.
Tom: But it's not a good idea to run your car with retarded timing over the long run. Among other things, you'll force the engine to run hotter than it's supposed to run, which will shorten its life. And you'll force it to run rich, which can eventually ruin your catalytic converter. http://www.cartalk.com/content/colum...bruary/08.html
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Tom: But it's not a good idea to run your car with retarded timing over the long run. Among other things, you'll force the engine to run hotter than it's supposed to run, which will shorten its life. And you'll force it to run rich, which can eventually ruin your catalytic converter.
Everything in the above statement is false. Tom should find another job.
they didn't mention the evils of the other end, running gas thats too high octane for the engine causes serious carbon build up problems, and the related sludge issues. which if you do some research is an issue with a fair number of toyota engines. thats why they tell us to use such a light weight oil, lighter oils take more crap before they get thick enough to cause problems.
having watched the ignition timing and mileage on my scanguage I agree with toyota's call to change the fuel from premium. its working better for me in every way I can measure.
Octane advice from Car Talk...
when I came across this in on cartalk.com. Don't know if anyone else on the forum listens to their radio progam, but I've always found them to be both entertaining and pretty spot on. Anyway, here was there response to a similiar question on premium fuel use;
Linear Mode
