FWIW gas octane mixes close to linearly (it's not totally linear, but it is close). So if you want 89 octane, you also have the option of putting in 1/3 of the 93 octane and 2/3 of the 87 octane. And with many stations/pumps, mixing your own octane grade (from a combo of the cheap grade and the high grade) is often cheaper to do than just to pump the mid-grade.

NOTE: If you are going to mix your own grade, always put the high grade stuff in first. The reason is that the gas doesn't totally mix right away, and so you generally want the higher grade stuff in first, so if/when you get unmixed gas you get the higher grade stuff.

Manufacturer recommends 91 octane.We have 87,89 & 93 octane around here.I never thought about mixing. I might try it and see how the Lude runs.It runs a lot better with 93 but a mixture of 91 might work just has well.

Running premium in the Prelude has not gotten me any better gas mileage. I also added the Bosch Platinum + 4 spark plugs and it hasnt helped any either. Fixing to change the wires,distributor cap and rotor. Maybe there will be a change after I have done that. One of the guys at work says I am wasting my money doing this because any added gas mileage will not pay for the added parts. But the car has almost 140,000 miles on it and needs the maintenance whether it helps the mileage or not.
I sure had hoped the premium would get it a little better gas mileage but you cant get everything.

if your engine is not pinging, premium will not help mpg. if ,however, it allows you to advance timing, then it might help.the difference between 89 and 93 octane is so little, it probably won't allow enough timing change to make a difference.

The mpg is 10%+ higher in my '97 RL on premium than on regular and premium is only about 7% more expensive here, so it makes sense. The big thing that many people with FlexFuel cars aren't keying in on is that E85 is only $2.97 while regular (E10) is $3.87. That's a 30% difference, and most FF cars only lose 20-25% mileage on E85. In my '94 Vigor it's definitely more cost effective to use E85.

I was running 85 (we have it here in the Denver area) and switching to 87 - mid-grade, I got enough MPG increase to warrant paying extra for better economy. I figured I was saving $3.00 a tank by using 87 vice 85. I saw a 10% increase in MPG over at least 4 tanks. I am currently experimenting with my first partial tank of 91.

I wish E85 was more readily available here. Seems that the only public fuel stations here in the DC area that sell E85 are inside the DC beltway (and even then there are only a small handfull) I avoid that area like the plague. One would think that the huge stations here that specialize in low cost fuel like Sheetz or Wawa would be all over it. Their stations are always in high traffic areas and they always sell a high volume of fuel.

-Jay

I used to live out west, and they would frequently have 86 as the regular, 85 in some places.

"Back East" 87 is regular, 89 is mid (aka Plus), and 91 is premium (although Sunoco stations have FOUR grades, 87,89,91,93).

I've never tried anything but 87 in my car.

LOL, Sunoco... If you remember years back Sunoco used to have that dial on the side of the pump where you were supposed to select which additives you wanted in the gas. Grandpa always said that it didn't do anything but make you feel like you're doing something when you turned it.

-Jay