I am once again impressed with the F. Finally got to take her on a small road trip to vegas which for me is about 250 miles one way. Lets just say the trip was made in well under 3 hours, in the area of 2 hours and 25 minutes, if you exclude the stop for lunch. The car is very stable at triple digit speeds, but that is something i expected. What i didnt expect was the gas mileage that we averaged going across the desert at the speeds we were going. The computer stated that the average mpg was 31.5 and after filling up i could confirm that the computer wasnt off by much. I put 275 miles on the car and took about 8.9 gallons. Do the math and the computer was just a little off. The return trip was a lot different as there was just a ton of traffic and the return trip was about 7 hours long with all the stop and go traffic.

And as a side note, while I was in vegas i figured i would see at least one or maybe two isf but i didnt. It seem like the m3 and evo is the new civic on the road.

 

Great news. I had the same experience last weekend as well. I averaged around 28 mpg while averaging probably 85 mph on the highway with some stop and go traffic. Love the F for so many reasons

 

Same here, I averaged 28.2 @ 80 mph on a new 2K mile motor. Bythe way, this car will run on 87 octane no problem. You may lose a little power but not much!

 

I feel the EPA ratings for the IS F are way too conservative. Although I think the posted numbers are great, the IS F is capable of getting phenomenal fuel mileage.

 

Very nice drive!, wish i had long smooth roads here in new york, but traffic everywhere which sucks!

 

Why would you even consider doing that? Yes you can to a point, but only in an emergency as stated in the manual. I could understand if 91 was not available if you were in the middle of nowhere, but on a consistent basis?

 

I agree, this car impresses me every time I drive it. I can honesty say I enjoy the F more than any other vehicle I have owned which included an IS 350, and several vettes, and stangs.

 

Bulls , I only run this when I make my road trip to Waco which is about 2 tankfulls a month. The roads are bad and plenty D.P.S. If I can't drive it hard I will save on the fuel price.Also my wife is usually with me and hot rodding is out of the question!

 

So on average there is about a .25 cent difference between 87 & 91 here in Cali...

Is saving $4 on the fill up really worth the potential long term ill effects of engine pinging, from running the 87 Oct fuel on two full tanks a month??

On an emergency basis I can undestand, maybe adding just a few dollars of 87 till 91 can be found..

But to fill on 87 when the engine requires "Premium Grade" is just not a good practice in my honest opinion.

Joe Z

 

To add to what Joe said, running a lower octane will result in the ECU pulling timing to compensate for it. The result is a reduction in performance and often the engine works harder and ends up lowering your MPG. The best is to stay with the recommended octane unless the engine has been tuned for it.

 

Man, you guys are hard on a newbie! I agree with all your statements above ,but would just like to add that I have personaly drove the car with a mixture of 93/87 octane and the car does not ping or run bad. Of course that is probably an average of 90/91 octane.Just wanted everyone to know that your motor will not grenade on you if you want or need to run the cheap stuff.By the way I only run top tier gas without ethanol ,Chevron,Shell ,Texaco.

 

i agree with joez. ill spend the extra four dollars at the pump for the peace of mind. however i also agree with gsz in that you can run 87 oct in a pinch. i have never practiced this with the f, but i was forced to when i had the infiniti g35. i was traveling through new mexico out interstate 40 and every station seemed to only have 87 oct available so i was forced to fill up with 87. i will say that i didnt notice any increase or decrease in performance, but i was also running cruise control at 75 mph. i will say this though there was no ill effect on gas mileage and to be honest on that leg of the trip i actually had a little better than average mpg on the trip but i think it was due to the major decents especially on the east side of albuquerque.

i will be driving to utah next week so i will have another road trip to compare mileage too in the f. the only problem is the open road gets boring and the right foot tends to get a little heavy. i will see what affect cruise control has on this trip.

 

Under these conditions 87 will work fine. It's only a real threat when you ask the engine to produce serious power. You could cruise at 75 mph on a flat/downhill with a 15 hp engine. An engine as large as the F's will not be anywhere near needing premium if all you're doing is long distance highway cruises. Just don't expect to pull a trailer uphill or climb the Grapevine at 100 mph with 87. It won't like that at all.

 

True ,I know ,I have proved it! With the F you can have your cake and eat it too. Like I said before If you want it will run fine on 87 octane but it is your choice under your conditions. I would never run it hard on 87, but if you do, no ill effects,just lack of performance. Just like my old G-35.