Re: New to me 98 740i octane & mpg ?? (archive)

I have be running my M73 on 87 octane for more than one month now, and outside of perhaps not getting as much power and/or fuel economy as I might get with higher octane fuel, I cannot detect any problems.

Our cars have what are referred to a knock sensors. They devices can and do detect spark knock long before we can hear it, and retard the timing enough to prevent knock from being heard or doing any damage, or causing any problems.

While there are those who will argue this with me, I haven't had, nor expect to have any problems. IF I drove with my foot in it all the time, then I would run the highest octane I could get, which here in CA is 92 only.

With the V12, I don't have to use much throttle to get the car to do what I expect of it.In fact, I have only floored it once, simply to see what it would do. And I am used to the 385 cu.inch (6.2L) cammed Impala SS with 3.73 gears that I traded in on this car.

As long as some computer tuner has NOT messed with your factory stock 740i computer, I see no problem with trying a full tank of 87 octane.

Try it, you just might like it!

DHG

I just picked up a used 98 740i--- white / tan Lots of upgrades--- WOW what a sweet car.. Book says 89 octane OK -- 1) does it run better with 92? 2) What is to expected on MPG? freeway at 80 relatively smooth and around town - stop and go-- thanks in advance
It really is niceer than I thought it could be. I just sold a 92 735i, real nice but time for a better long distance car.

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