I have had my RX8 for about 5 months now. I have avg'd 200ish miles per tank and I am ok with that (it almost doubles my old cars mpg).

My last tank of gas lasted to 280 miles to a tank, and my current tank is just about the same.

I have not changed the way I drive (foot to the floor when possible).

The weather has been cooler (95 vs 79 degrees). Is this car that finiky with the heat or is it something else?

I live in Houston which adds Ethanol to the fuel which can be up to 10% of the mix, and I saw on the news that due to hurricane Ike they were relaxing the mix rules for the fuel.

Is that what is responsible for my incresed mileage, or is it the temp?

The difference is too big for me to just ignore. If this has been covered before, I appoligize, but if my old 396 cubic inch motor suddenly jumped by that big of a percentage I would be asking the same question. Is there some mystical rotary math I am not aware of?

 

How many miles on the car when you bought it? Rotarys tend to get a little better mpg after break in.

 

damn I average 190 miles a tank... an extra 90 would be phenomenal!

 

It could be the temperature.. Because colder air is more concentrated giving you more oxygen.

But I never noticed a jump from 200 to 280... maybe if I did all city vs all highway.

 

my record is 295 miles on a tank of gas. usually i average around 200.

i got the 295 with the cobb accessport in economy mode.

 

I have everyone beat, at least that's what swoope tells me, averaging 27mph on the highway, longest tank lasted me 331 miles. No AP for me...just found the sweet spot with the cruise control. All my mods listed in my sig...

 

averaging 27 mph on the highway .. eh..

 

I got in with the trucks in the slow lane at 55-60 mph for 236 miles round trip got.... 29.5 mpg. It's hard to keep your foot out of it for that long! Don't know if I could do it again.

 

The increased mpg changed from one tank, and was not a gradual thing. I have 13k miles on the car.

My driving style has not changed....weird.

 

no, they dont. this is a myth. no evidence to back it up whatsoever.

 

well the most i've gotten out of a tank w/o changing driving habits is 230mi. I think you might have been cruising more that tank....ie constant rpms so the engine did less work over time.

But even then i don't think that can speak for a boost of mpg that you got. The only thing that would do that is if you did only highway with cruise control on between 55-70mph. Even that is still unlikely IMO.

 

I rarely fill my tank up and if i do, I rarely note the mileage for the caluclation at home. (I keep it under 1/2 a tank for less weight )

However my RI<->MD trips are generally 270-310 miles per tank. And that is normally with cruise control on at 75-80mph, hard acceleration out of rest stops, etc...

 

What if I retrofit a 24 gallon tank onto my RX -- then I can double my mileage!...If you can't calculate your mpg, then don't start or contribute to a mileage thread.

 

WIN!

 

best- 23.5mpg
worst- 11.7 mpg
avg- 16-18 mpg

 

I can calculate mileage. I just generally don't. The OP was quantifying it in terms of 'miles per tank', which is exactly what I responded with.

My particular best every was 24.8mpg. My average for the long trips runs around 21-22mpg, normal to and from work is 18-20mpg, and worst ever from a weekend of driving just for fun was 17.1mpg.

Happy?

 

.... WHAT?!

How can you achieve this mileage, but no one else can?

Seriously, accelerating hard to start, cruising at 75-80 mph...

Question: At what point do you refill, and calculate estimated remaining miles to get to the 270-310?

 

Not your normal MPG thread ....................


Yea right .

 

and where would that sweet spot be?

 

who says no one else can? long trips will often get you around that point if you are cruising at 75mph. it takes you pretty close to empty but still gets you there.

 

Yeah cruising to FL from Mass at 72mph averaged 290 miles to a tank, that includes rush hour traffic also

 

Damn awesome. Dude i hate 95/295/395/495. I went from Philly to Savanna, GA once...ugh. its a though drive at night.

 

I honestly don't know why I get more than other people. I drove Blackenedwings' 8 after his access port, and I swear it felt nearly identical to mine. I do completely wipe the ECU every other month or so messing around in the engine bay, so I know it doesn't get stuck in an old fuel trim very long.

And the 270-310 miles on the tank are not estimated or calculated. Those are actual observed miles.

My last trip down to MD I filled up here:
Shell: 1025 Eddy Street, Providence, RI, 02905

And then filled up here:
Pilot: 600 S Pennsville Auburn Road, Penns Grove, NJ, 08069

I remember it very clearly since I have to turn in gas receipts for work anyway (they pay mileage, but still want proof of where I went), and I was pleased I made it to that gas station without running out, even though I detoured and sat in some traffic.

MapPoint shows that as 292.4 miles shortest distance, my odometer was at exactly 300.1 miles. I didn't drive straight route, as I detoured to avoid heavy traffic through New York before the George Washington Bridge onto 287 -> Hutchinson River Pkwy -> Cross County Pkwy -> Saw Mill Pkwy - > Henry Hudson Pkwy -> back to 95. Adding this extension puts it to 294.7 miles via MapPoint. So there is apparently a slight discrepancy between my odometer and MapPoint (don't know which is more accurate), but either way, that trip was at least 294.7, at most 300.1

I don't have my receipt, turned it in to company for my expense report, but I believe that was 14.9 gallons, the light had been on for a while, and the needle was well below the bottom line.

294.7 / 14.9 = 19.7
300.1 / 14.9 = 20.1

If you want I can dig up information on my other trips and post that as well. These are not estimates, I am actually getting these numbers. And yes, I redline it all the time. It is a rare day that I don't hear the beep under full power at least 3-4 times, and frequently it is more like 10+.

A true 'complete tank' of 15.9 gallons will get you:
15mpg = 238.5 miles
16mpg = 254.4
17mpg = 270.3
18mpg = 286.2
19mpg = 302.1
20mpg = 318.0
21mpg = 333.9
22mpg = 349.8
23mpg = 365.7
24mpg = 381.6
25mpg = 397.5

Granted, no one fills up on exactly empty on long trips, so the actual amount per tank is less, but those are theoretical maximums, so these numbers aren't as absurd as they sound to you.

Next time I take a trip, I will bring a digital camera, and take pics of the gas stations, the odometer, and the receipts, if you still don't believe me.

 

I normally fill up just before E or as soon as the light 'dings'. Which is normally 13-14gal of gas. So i have about 1.9-2.9 gal remaining in my tank when i gas up.

Maybe your on to something with the constant reflashing of the ecu...

 

there's no need to prove anything or reset anyone's ecu. if you drive highway at a reasonable speed for a great distance (like 300 miles), you'll get good mpg. those who aren't getting that (myself included) aren't getting it because you aren't driving all highway miles. and jumping onto the highway for a few miles before getting off and finishing your commute doesn't count either.

i have almost all short distance trips to/from work or the train station. i usually get about 200 miles/tank but that's b/c my commute to work is 6 miles and if i am in NY, the ride to the train station is about 4 miles. any long trips up to boston or on the spring run last year get me about 300+ miles/tank to and from. it's not hard to do except for that lead foot that always wants to make an appearance.