06 TL Fuel

Nope, low grade for me. Runs great.

I bet the gas mileage and power is not as good as running premium! The cost might not even be less if the gas mileage is significantly lower with mid or regular gas. It's a good thing the TL will retard the timing to prevent knock and save the engine from destruction.

It would be nice to know if it's worth the difference in price between the gas grades. My guess, from experience with a different car, is the difference in cost per mile would be small. Let us know how much money your saving/loosing by using a lower grade of fuel then what the manufacturer recommends.

Well, Acura calls for 91 octane fuel. You could fill up with premium, (93 octane), run it down to half a tank, fill up with plus grade, (89 octane), then run it down to half a tank again, fill up with premium, (93 octane), and keep repeating this routine. You should end up with 91 octane, or close to it, and that's what the manual calls for. However, you're only saving 10 cents a gal. for 8 or 9 gal. of gas every other time. Is that small savings worth all the hassle? Assuming I've done the math right of course. And you know the old saying about "assuming" anything, right?

I've run this experiment using my Sienna. I've run a number of tankfuls of regular or premium fuel in succession so the engine computer should have settled down. I've done this several times with similar results.

In town the car gets the same mpg whether I run the recommended octane or 87. Seasonal/regional differences in fuel seem to make more difference in mpg than octane rating. Last December (long highway trips) I got 24-26 mpg on the highway outside cities vs. 22-23 when I filled up in places where the pumps indicated a pollution-reducing blend.

Fuel blend issues aside, on the highway the car gets slightly better mpg with premium fuel; the mpg advantage grows with increasing speed; I get very little benefit at 60 mph but a measurable 2 or 3 mpg better at 70-75 mph. The harder the engine works (heavy load, mountain driving, etc.) the more mpg premium delivers. On the other hand, running at 60 mph is more fuel efficient than 75 mph so the most economical way to drive is with 87 octane at slow speed. I've recorded as high as 27 to 28 mpg (vs. EPA 23 mpg) on the highway using premium fuel, cruising at 75 mph under very favorable conditions (high plains, no traffic, Mobil 1 oil). And, no, I didn't try 60 mph while driving across the plains.

Then again, if you drive your TL as if it were a minivan, perhaps you're in the wrong car...:-) I've not run similar experiments with my Corvette.

YMMV