I seem to have ended up with an 'in the middle' car for the mpg. I know some people are getting 20+ no matter what they do, and others can't get above 15 mpg despite driving like an old, sick grannie. Myself I drive conservatively. I shift between 3500 and 4000 rpm, and generally cruise around 2500-3000 rpm. Getting about 16-18 mpg regardless. My current tank will be very telling. Lots of highway driving between 70-80 mph (3500-4000 rpm). So far it isn't looking too promising (120 miles and I'm one notch above half-way). Won't know for sure til I get to the gas station and fill up though. I have 1200 miles on the car for the record.

 

O.R.A. had it right, the light is useless as a measuring device to figure MPG figues.

Here's is what to do - START doing this the next time you fill up.

1) Try to TOP OFF your gas tank manually with the pump without overflowing. WHY? Because auto-shutoffs don't all stop at the same fill level, even the same pump from one fill to the next.

2) Reset the trip odomoter & NOT THIS FIRST TIME, BUT EVERY TIME THEREAFTER save each slip and WRITE the TRIP ODOMETER mileage on it, then reset to '0' miles.

3) Divide the number of miles driven (trip odometer reading you wrote on the slip) by the gallons as shown on the slip. Use a caculator and USE the tens and hundredths of a gallon reading if shown.

4) Repeat 1-3 to see your TRUE MPG for each tankfull.

NOW for the OVERALL MPG OVER MANY TANKS WORTH OF GAS. As you accumulate slips, save them somewhere. (I enter them in a spreadsheet, but paper and pencil will do)

1) Keep a running total of miles driven. Each time, add the next TRIP ODOMETER reading to the last total miles you have. (NOTE - DON'T use that first slip in this total!)

2) Keep a running total of gallons driven. Each time, add the next gas station gallons reading to the last total gallons you have. (NOTE - DON'T use that first slip in this total!)

3) Divide the TOTAL MILES / TOTAL GALLONS to get the AVERAGE MPG.

The longer you keep records like this, the more accurate your MPG reading for the car will get. Any small errors will get averaged out. And although some of you may think this all too simple, others may not. Math can be a challenge, hopes this helps.

 

Sorry to dump on an optimistic theory, B-Nez, but the idea that cold weather will help mileage for cars from hot-weather areas isn't working for me. I got bad mileage in Washington, DC heat and humidity. Now we're having delightful fall weather (65 highs, 40-50 lows) and I'm working on one of my worst tankfuls. At 1,900 miles.
Mitch

 

New york city here- so not hot weather- and poor milage as well.

anything from 11 city to 15-16 highway

 

Mine's got about 1000 miles on the clock so I've filled it up about 4 times now - I've consistently got ~250 per tank which works out at 18mpg. The kind of driving I do is mostly freeway at betwen 80-85 mph sometimes a little faster but rarely slower. A very little bit of town driving is done.

I'm pretty sure if I was to drop it below 3,750 rpm crusing (which is about 70-75 mph) I would increase my mpg to over 20. If I drove at optimum "highway" speeds (which is 55 mph I believe) I would probably get the posted 24 mpg easily.

From what I've read the engine opens up an extra port at 3750 and I suspect it's this that guzzles the fuel.

 

I have a suggestion. Why don't we compare information.

Transmission/car type type: 6 sp GT

Highest average speed in our daily commute = 50 mph

Average distance traveled 1 way = 17 miles

Average time taken = 35 minutes (accounts for stop and go)

Octane of gas used and brand (if known) = 87 oct Penn (Sam's)

Ambient temp during commutes 76/91 F

Average mileage based on miles driven by gallons used = 17.7 mpg city. I usually go to about 240 miles to tank and calcualate the mileage it is from 17 - 18 (varies week to week)



We should be able to figure out something. Besides the geographical and environmental differences, there are our driving habits to consider.

 

My Mileage Record is below, mine seems to be middle of the road, averaging 17 around town, and 20 highway. Made a nice long roadtrip to california, and the heat there made little difference on the mileage over my around town driving up hear in washington.

My overall average, with about 80% highway, is 19.34 mpg

 

However, I don't believe "highway" is very meaningful. I think it's officially 55 mph or something very slow. If you drive at 80 most of the time the mpg will vbe significantly lower. This is of course obvious but I do think we need to factor in what you *really* drive on the highway not just some fictional value used by the car industry. What was your average "highway"?

 

Ok, here's something weird for you guys- I get my best mileage on the highway driving over 70. For example, drove to Maryland this past weekend on 95, going between 75-85 the entire way. Got 24 mpg. Between 55-65 I get closer to 20 mpg.

I get crappy mileage when I drive in the city in stop and go- my personal worst so far has been about 14.9, and that was last week in all stop and go traffic.

 

this is to 8_wannabe

ppl. in laredo LOVE the car, there is about 6 of them here so far, they stop and look at every light. they can't get enough of its style ..it makes me feel...hmmm :D

 

Hot climate here, and I'm getting between 18.3 and 19.7MPG every tank (9 recorded so far), no matter the city/hwy ratio. Car currently has 3300 miles. I don't believe anything magical happens at 2000 miles. I do believe my car gets slightly better mileage (<1MPG) with 89 octane than with 93.

 

Good idea.
I put your data in an Excel sheet. Added mine and attach it here.
Unfortunately this system doesn't allow XLS files :-( I had to ZIP it.
The next person can download it, add his/her row and attach it again? Do you guys think that'll work?

-Peter

 

i think im getting off like a bandit... im getting 18-20 and my car lives at 6k rpms :D

 

A lot of it depends on your time at idle. I've noticed when I sit idle at lights for a long time in traffic my car gets bored and starts sipping gasoline like lemonade. I drive the long route to work in the mornings now because I think it uses less gas to go 5.0 miles around and be moving almost the entire time, than to go 3.0 miles and be sitting idle for longer.

 

nice graph fuzzi

 

Guys I guessI was wrong. That tank made it to almost 245 miles before I got to the gas station. I drove it for atleast 20 miles with the empty light on and the air conditioning and radio off and windows down. I guessthat means my mileage really eneded up being like 17mpg. Not really sure. I know that I drove like 6 miles with the gasnozzle sitting below the empty line. I really thought I was going to runout and breakdown before I got tothe station. I think when the emptylight comes on you stillhave 2 gallons left to go which is pretty stupid. When it came on for me on this tank I only had 215 miles on the tripmeter and it made it to almost another 30. I bet you that if I didnt drive very slow and with allthe stuff turned off I wouldnt have made it there. I cant believe this. I hate driving the Rx8 like this just to get this kindof mileage.

 

my "Highway" was my typical Road-trip style driving... Long streches of about 80-95 mph, then a stop at a rest stop and/or gas station every once in a while... some short stints over 100, but that is only at times where coming over a hill into a beautiful valley, with a clear view of what's ahead of me... just begs my foot to the floor.. :-) I thikn the biggest impact on the cars mileage, like most cars, is accelleration. Which makes since physics wise also.

 

I just filled up anothertank last night. I want you guys toknow that I have figured out my Rx8 tank always has 60 miles on the tripmeter by the time the gasnozzle gets to the 3/4 mark. This was the samething I got on the last tank 60 at 3/4 full. Is this thesame for you guys too?? That is with only city driving btw. I guess this means that if I keep going atthis rate then240 city miles a tank isgoing to be what Im always going to get. Wait but for my mpg I divide that number by 14 right? Or is it 15? If its15 then that means my tanks arecoming up 30 miles short of 18 city mpg. If its 14 then I am almost right at 18mpg in city. I still think this is pretty bad. I expectedtobe able to get 300 miles atank in only city driving.

 

The only reliable way to measure mileage (well, the MOST reliable way) is to always fill up completely (top off the tank), and divide the amount of miles you've gone on that tank, by the gallons it took to fill it back up. This whole using the gas gage thing just is not accurate, and if that is the way you are figuring out your mileage, no wonder noone seems to be getting the right milleage. I actually track my mileage on every tank (hence the graph that i showed earlier) so i don't even have to use the tripometer, because i can just go off my odometer... for instance, as of my fill-up this afternoon, i have driven 6273 miles, and used 323.54 gallons... that's a mileage of 19.39mpg... not to bad i think...

 

*sigh*
Any chance you'd like to just give us your *actual* mpg? It's not like it matters what size the tank is, after all...

 

You have the patience of Jobe, mngpao!!!

 

Thanks for the comment, but actually, I got a speeding ticket a couple of months ago and if I can go the rest of this year without another ticket the ticket gets dismissed. Therefore, I use my cruise control religiously.

 

JeRKy 8 Owner, you seem to be VERY RESISTANT to any and all advice given you! Several posters, including myself, have told you within this thread that you ARE CALCULATING MILEAGE INCORRECTLY, then explained how to do it right. STILL, you persist to use your fuel guage and this "14 right? Or is it 15? If its15" insanity.

So you offer no alternative opinion I can come up with... Either you are just plain stupid, you can't read, or perhaps you're a troll posing as an owner, IMHO.

Otherwise with 1/2 a brain (or NO brain, if you can simply follow directions and use a caclulator) you would know EXACTLY what your mileage was, and STOP THIS USELESS (and incorrect) WHINING about how bad mileage you're getting.

Sheesh!

 

Well said, spinner. Sheesh indeed.

 

I'd be very surprised it the differences aren't simply (or mostly) driving conditions (stop & go commute, highway at 85 or 55, etc.) and driving style (throttle position, revs, etc.).

Even when I am trying my best and I think I'm driving as conservatively as I can, my girlfriend can still get better mileage out of the same car than I can.