Factory Freak with gas mileage?
Thread Starter
Senior Member
Joined: Dec 2002
Posts: 883
From: Stevens Point, WI
Factory Freak with gas mileage?
I just returned from a 131 mile trip.
-60mph hwy driving for about 95% of the time.
-I filled up before I left, filled up when I got home. Same gas station, same pump, same gas.
-131 miles and it took 3.4 gal to fill it again.
-131 / 3.4 = 38.5mpg!
Last month I went on a long trip and filled up before and after the trip. I don't remember the numbers, other than I was going 85 the whole way, cruise control on, and I got 30.5mpg that time.
I can't believe some Max owners get in the low 20s on the highway. I am thinking about getting a 1st gen Altima 5spd, but now I'm afraid that I'll get worse gas mileage with the 2.4L!
My car - 95 5spd w/ Injen + free flow muffler. 149,000 miles. Currently getting a code for 0503 (rt. frt. O2 sensor).
All 4 Potenza RE950s set at 33psi.
It is constantly waxed, and I wiped it off with some quick detail spray this morning, so it is very smooth, but I don't think the slight aerodynamic increase from the slick paint would make much difference in gas mileage.
Does anyone else get unusually GOOD gas mileage???
-60mph hwy driving for about 95% of the time.
-I filled up before I left, filled up when I got home. Same gas station, same pump, same gas.
-131 miles and it took 3.4 gal to fill it again.
-131 / 3.4 = 38.5mpg!
Last month I went on a long trip and filled up before and after the trip. I don't remember the numbers, other than I was going 85 the whole way, cruise control on, and I got 30.5mpg that time.
I can't believe some Max owners get in the low 20s on the highway. I am thinking about getting a 1st gen Altima 5spd, but now I'm afraid that I'll get worse gas mileage with the 2.4L!
My car - 95 5spd w/ Injen + free flow muffler. 149,000 miles. Currently getting a code for 0503 (rt. frt. O2 sensor).
All 4 Potenza RE950s set at 33psi.
It is constantly waxed, and I wiped it off with some quick detail spray this morning, so it is very smooth, but I don't think the slight aerodynamic increase from the slick paint would make much difference in gas mileage.
Does anyone else get unusually GOOD gas mileage???
A few weekends ago a friend and I took a trip in his 89 SE 5spd CAI/No muffler + crap in the trunk, tires at 30-34psi (I think 34 but cant remember).
We got 529.8 miles on the tank, pretty much all highway plus a few runs down the track. Highway speeds were mainly 85mph, but there were a few runs up to triple digits.
He also had brand new tires, bridgestones, I forget the model.
We got 529.8 miles on the tank, pretty much all highway plus a few runs down the track. Highway speeds were mainly 85mph, but there were a few runs up to triple digits.
He also had brand new tires, bridgestones, I forget the model.
theoretically, the lowest speed in the highest gear with a sustained acceleration will give you the best gas mileage.
in other words, in 5th or o/d, being at the lowest cruising rpm with little to no change in acceleration will give you the best mileage.
in other words, in 5th or o/d, being at the lowest cruising rpm with little to no change in acceleration will give you the best mileage.
i got 31.275 or something close to that one time when i was driving around the city, and i think if i had done more hway i would have gotten something like what you've gotten. its all about self control and the way you drive 
Dyno plot says I have the most area under the Administrator curve
Joined: Jul 2001
Posts: 7,064
It's inaccurate to measure fuel mileage via that method over that short of an interval. I don't doubt that you got over 30 mpg, but if you're claiming 38.5 then I have to call the methodology into question. Even though you used the same station and pump, maybe it just shutoff a half gallon late last time, and a half gallon early when you filled up again. That means you used 4.4 gallons, not 3.4, and your mileage is now down to 29 mpg.
That's why you need to measure fuel mileage like this over the longest interval possible, like a full tank. When you're dealing with a 16-17 gallon fillup on an 18 gallon tank, that fillup cutoff point variability becomes much less significant statistically, and therefore your measurement more accurate.
That's why you need to measure fuel mileage like this over the longest interval possible, like a full tank. When you're dealing with a 16-17 gallon fillup on an 18 gallon tank, that fillup cutoff point variability becomes much less significant statistically, and therefore your measurement more accurate.
I got a high of 28mpg one time doing all highway driving, with an average speed of ~70-75MPH (meaning I went up to 90-95 a few times).
The trick is to keep your speed below ~75-80, while averaging 60-70 or so... 'cause when you rise in speed above ~55MPH, your fuel consumption rises as a function of some sort of curve (logarithmic?) I can tell this by comparing 75MPH to 80MPH on the highway. At 75MPH the engine is mostly quiet, while at 80MPH I can start to hear the hum of the engine over the road noise while maintaining constant speed. And that's only a 5MPH difference in velocity. The engine has to work harder at 80MPH to overcome aerodynamic drag to maintain constant speed.
The trick is to keep your speed below ~75-80, while averaging 60-70 or so... 'cause when you rise in speed above ~55MPH, your fuel consumption rises as a function of some sort of curve (logarithmic?) I can tell this by comparing 75MPH to 80MPH on the highway. At 75MPH the engine is mostly quiet, while at 80MPH I can start to hear the hum of the engine over the road noise while maintaining constant speed. And that's only a 5MPH difference in velocity. The engine has to work harder at 80MPH to overcome aerodynamic drag to maintain constant speed.
Thread Starter
Senior Member
Joined: Dec 2002
Posts: 883
From: Stevens Point, WI
Originally Posted by SteVTEC
It's inaccurate to measure fuel mileage via that method over that short of an interval. I don't doubt that you got over 30 mpg, but if you're claiming 38.5 then I have to call the methodology into question. Even though you used the same station and pump, maybe it just shutoff a half gallon late last time, and a half gallon early when you filled up again. That means you used 4.4 gallons, not 3.4, and your mileage is now down to 29 mpg.
That's why you need to measure fuel mileage like this over the longest interval possible, like a full tank. When you're dealing with a 16-17 gallon fillup on an 18 gallon tank, that fillup cutoff point variability becomes much less significant statistically, and therefore your measurement more accurate.
That's why you need to measure fuel mileage like this over the longest interval possible, like a full tank. When you're dealing with a 16-17 gallon fillup on an 18 gallon tank, that fillup cutoff point variability becomes much less significant statistically, and therefore your measurement more accurate.
I don't drive on the highway very often. I wanted to see what my mileage was on a nearly 100% highway trip. If I would have waited another 150 miles, it would have dramatically decreased the mileage due to a lot of city driving.
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