People,
Its Amazing To Me How So Many Of Us Dont Understand How To Test Fuel Milage. Please Try This-
Warm Up -
Need To Be At Full Operation Temp, Warm Trans And Diff. Your Rotory Isnt Anyware Close To Efficiant Till Shes Hot, Cats Warm, Ect
Fill The Tank -
Find A Gas Station Near A Good Section Of Road That You Can Cruz Along 55 To 60 Mph. Fill The Tank, I Mean Fill The Tank All The Way! Use Premuim. Reset Your Trip Meter
Drive It-
Down The Road, 55 To 60mph For At Least A 35 Mile Run. Dont Stop, Stay Out Of Town.
Fill It Again-
Fill It, I Mean Fill It! Do It Know, Not Later. How Much Gas Did You Use!!!
Ill Bet Your Surprised!
Do The Math-
Dont Use The Fuel Gauge To Try To Figure Your Milage. Take The Miles On The Trip Meter And Divide By The Fuel You Added. No Fuel Gauge Is Accurate!!!! The Rx8 Has A Fuel Tank That Gives You Plenty
Of Resurve! Its Also Divided In Two.

Tips-
Stay Away From Higher Rpm !!! Secondary Port Opens At 3800rpm, Aux Port At 6200. Same With The Secondary And Aux Fuel Injectors.

Please Give This A Try, Post Your Results.


Good Luck!

Down The Road, 55 To 60mph For At Least A 35 Mile Run

We know you really meant to say for at least a 250 mile run - since a 35 mile run would only use around 1.5 gallons of gas, and then the normal error/variance on fillups would mean significant error on your mileage calculation. Right? ;)

Anyway - your method (warm at start of test, slow highway cruising) will generate a maximum MPG number, but won't represent typical real world mileage with cold starts and city driving mixed in. Sure, it's nice to know what the maximum MPG the car is capable of, but real world costs and real world mileage are what's important.

Regards,
Gordon

........Post Your Results.........

Care to share your results?

I don't use my fuel guage to measure my mpg. I use my trip meter, and the number of gallons that were needed to fill the tank. I perform this calculation every time I buy gas.

I tried different brands, and octane levels as well with no change...so I decided to use one gas station, one pump. I will wait for the pump if it is in use....

I am averaging 14.5mpg

I drive a mix of city and highway, probably 55/45 respectively. My mileage has dropped of significantly as cold weather has moved into my area. During the summer, I was getting about 200miles to 13.5 gallons. (14.5-8mpg) Now in the winter 180 miles to 13.5 gallons (13-13.3mpg).

I understand that the 8 has a saddlebag type fuek tank. As fuel transfers side to side, the fuel gauge will read differently. I tend to fuel up when the light comes on, and it is typically around 13.5 gallons.

Warm Up -
Need To Be At Full Operation Temp, Warm Trans And Diff. Your Rotory Isnt Anyware Close To Efficiant Till Shes Hot, Cats Warm, Ect


Is this true? In the Mazda Owner's Book (or is it the little extra pamplet they give you) it says something along the lines of "don't warm up your car. As soon as the engine runs smoothly, drive" under the "how to get better mileage" section. I can't remember exactly where it is, but it's definitely in one of the things Mazda gave me. So I don't warm up the engine anymore. I just wait for the engine to settle then go.

When you are letting your car warm up in the driveway you are getting 0 mpg. I drive mine cold but keep the RPMs lower than 4K until it warms up. You won't be getting 16 mpg driving it while it's cold, but anything is better than 0.

I Agree!
Many People Want To Know There Average Milage. I Just Feel Some Of The Bad Press The 8 Gets Are Do To Not Fully Understanding How To Calculate Your Highway Milage. That Is The Most Accurate Way To Do It. I Personally Like To Test It With The Owner In The Car, On Short Trips (less Than 50 Miles).

Its Amazing To Me How So Many Of Us Dont Understand How To Test Fuel Milage.
Wow, miles divided by gallons, how'd you figure that out?

Will try again but. Last nite I drove from Parker az to long beach 270 mi. full tank on warm engine. used cruse control, 6th gear,3900 rpm 72 mph, no air. reached lb with 1\4 tank fuel
will fill up today ;but worst case is about 21-22 mpg

I DRIVE all city miles during the week, and get the usual about 16 mpg (trip usually says 200 when i fll up) but whenver I take my 8 on the highway for a road trip (more than 100miles) it gets SIGNIFICANTLY better mileage- i.e., the diff btwn highway and city miles seems to be more in this car than cars ive driven in the past- so don't be too discouraged by poor city 'everyday' miles. I took my 8 on a 200 mile trip this past weekend, and got nearly 300 miles on the 'tank', and when I divided gas by my trip when i filled up, rolled in at about 22 mpg, and i wasn't sticking to just 55-65, had defrost (aC) on, and was cruising about 85-90 most of the way.

Haven't had a chance to check its effect specifically on the RX-8, but I learned long ago that using cruise control whenever possible has a significant effect on mileage in most cars. Constant speed cruising obviously increases mileage and cruise controls are generally more adept at maintaining a constant speed, avoiding even small variations, than one's right foot.

With this in mind, I switch to cruise control whenever possible in freeway driving and use the set/resume buttons in place of the foot pedal to control my speed. (Not going to enjoy the benefits of RX-8 handling/acceleration/braking on the freeway anyhow. I try to save the dinosaur juice for those opportunities to enjoy it.)

As I said, I haven't had a chance to check the effects on my new RX-8 yet since I'm still breaking in the engine and try to avoid long runs at a constant rpm, but in prevous cars I've noticed a difference of up to 20% in mileage when the cruise control is engaged.

I am a noob to cars and stuff. I haven't complained about the mileage, but I realized I was measuring incorrectly. I assume most of you know this, but some people might have been making the mistake I made. I was doing my calculations based off of the tank size, but I realized I was actually getting better mileage when I use the amount of gas I actually used. On average I would have to put in 13 gallons everytime, but I was calculating with 15.9.

I just thought this might be useful for some other people. :cool:

Must have something to do with that new math they have been teaching for 20+ years :)

Good tip ... I think that most people don't realize when the orange empty light comes on that they still have a good amount of gas left. I believe that my light comes on when I have 10 liters left, so every fillup it's around 50L (getting me back to 60L).

I'm sure that most people would be pleasantly surprised to see their mileage shoot up! ha ha

#litres added / #KM travelled *100 = L/100Km :D
I've kept track since new.........makes average very accurate

Good tip ... I think that most people don't realize when the orange empty light comes on that they still have a good amount of gas left. I believe that my light comes on when I have 10 liters left, so every fillup it's around 50L (getting me back to 60L).

I'm sure that most people would be pleasantly surprised to see their mileage shoot up! ha ha

Ya, I didn't notice that either. I'd just fill it up and look at the price, but I never really paid attention to the amount of gas I wsa putting in. All of a sudden it just dawned on me for some reason. :D

I'm not sure I know what to say... whew...

Really???

There are a\other threads that address this as well. I always use the gallons I pumped, and the miles on my trip meter. Otherwise, if you filled your tank from half, then you cant figure your mileage? I haven't gotten better than 15.5mpg in 14000miles with mixed highway/city driving.

nice idea jsh1120
i have thought about doing cruise control, but man, this car just makes me want to rev. i have been staying pretty low in rpms though. around 3k.

to spork or dark8
have your mileage improved from not letting the car warm up before drive? im interested in this information because ive been getting 13s and 14s even at my rpms.

thanks

Wow, miles divided by gallons, how'd you figure that out?
I hate to be some forum asshole, but this guy makes it sound like he's explaining the Theory of Relativity or something, its simple math guy. :rolleyes: If someone cant calculate mpg, theyre retarded.

Gordon makes the best point, I dont care what the max MPG's are driving like my grandma.

I hate to be some forum asshole, but this guy makes it sound like he's explaining the Theory of Relativity or something, its simple math guy. :rolleyes: If someone cant calculate mpg, theyre retarded.

Gordon makes the best point, I dont care what the max MPG's are driving like my grandma.


Yeah, it's kind of funny. I wonder if he's done a search. There are so many far more technical threads on mileage.

It never occurred to me in all my years of driving that there was any other way to calculate mileage than by dividing the miles driven by the number of gallons used.

It never occurred to me in all my years of driving that there was any other way to calculate mileage than by dividing the miles driven by the number of gallons used.

LOL - Actually, the metric guys divide the number of liters used by the number of kilometers driven. (The only other way I know.) By the way, the metric "l/100km" is different than MPG in that less is better.

you boob! duh.. of course you were getting an incorrect reading.. THE ONLY WAY to calculate gas mileage is miles driven by amount pumped... DUH! lol..... You should go back and get the g.e.d. It will be worth it! :)

merged 2 threads

to spork or dark8
have your mileage improved from not letting the car warm up before drive? im interested in this information because ive been getting 13s and 14s even at my rpms.

thanks
I can't really say. My mileage has DEFINITELY improved, but a lot of it comes from the fact taht I'm driving it more often (so some trips with the engine already warm) with also more freeway. So I have no idea how much comes from the engine being warm, the freeway driving, and the non warming up thing.

Sorry.

I am a noob to cars and stuff. I haven't complained about the mileage, but I realized I was measuring incorrectly. I assume most of you know this, but some people might have been making the mistake I made. I was doing my calculations based off of the tank size, but I realized I was actually getting better mileage when I use the amount of gas I actually used. On average I would have to put in 13 gallons everytime, but I was calculating with 15.9.

I just thought this might be useful for some other people. :cool:

Thanks for sharing openly Jasin. At least you're honest and man enough to admit you screwed up your calculations (here in writing) and are now smarter and doing it correctly. Intelligence is learning from your mistakes, stupidity is repeating the same mistakes no matter what you're told different.

I applaud you for that. :cool:

I have a gut feel that a good number of other problem mileage threads posts could be doing what you did, and posting lousy results because of it... but we'll never know.

Thanks to you, maybe some will read this and learn too. Good luck, and isn't it fun to be driving AND getting PGM (pretty good mielage) to boot! :)

Thanks for sharing openly Jasin. At least you're honest and man enough to admit you screwed up your calculations (here in writing) and are now smarter and doing it correctly. Intelligence is learning from your mistakes, stupidity is repeating the same mistakes no matter what you're told different.

I applaud you for that. :cool:

I have a gut feel that a good number of other problem mileage threads posts could be doing what you did, and posting lousy results because of it... but we'll never know.

Thanks to you, maybe some will read this and learn too. Good luck, and isn't it fun to be driving AND getting PGM (pretty good mielage) to boot! :)

Thanks. :D

thanks for your output spork

i guess ill just try varying my driving as well and see how it works out. ill test it for myself. ;)

I'm sorry to ask this question
but I'm all new

How do you guys calculate your mileage?
I want to calculate mine when I buy my RX8 soon

fill it up, reset one of the trip odometers, drive until next fill-up, divide the trip odo by the # of gallons pumped. I fill until the pump kicks off and never try to shove more in, so that i'm not a variable

I'm sorry to ask this question
but I'm all new

How do you guys calculate your mileage?
I want to calculate mine when I buy my RX8 soon

1. Fill your tank
2. Reset one of your trip meters
3. drive the whole tank
4. Fill the tank again... and note the amount of fuel it took
5. write down the trip meter distance,
6. mileage=miles driven from #5/gallons consumed in #4
7. goto #2

I disagree with G8rboy. For step 5, I note (instead of write) down the trip meter distance. For step 6, I write (instead of note) the amount of fuel to fill up again. I do not know where in the world you got your steps from, G8rboy, and am saddened.

fill it up, reset one of the trip odometers, drive until next fill-up, divide the trip odo by the # of gallons pumped. I fill until the pump kicks off and never try to shove more in, so that i'm not a variable


Therm8 does not have numbers next to his steps and it is IMPOSSIBLE to figure out what he's trying to say. Again, I am greatly saddened.

I disagree with G8rboy. For step 5, I note (instead of write) down the trip meter distance. For step 6, I write (instead of note) the amount of fuel to fill up again. I do not know where in the world you got your steps from, G8rboy, and am saddened.

what exactly does writing down the amount of fuel get you other than i use xx.xx gallons this tank.

Therm8 does not have numbers next to his steps and it is IMPOSSIBLE to figure out what he's trying to say. Again, I am greatly saddened

Lol, i;m sorry you're saddened, but that's as simple as it gets...
1. Fill it up (it=the car in question)
2. reset one of the trip odometers (there are 2, push and hold the little button above and to the right of the speedometer, the display should change from some value to 0.0. If your radio station changes instead, you're to far to the right and not enough above)
3. Drive until next fill-up (A: Drive being that thing you do with your car getting from one point to another, and B: next fill-up being what you have to do if you want to continue doing step A)
4. divide the trip odo by # of gallons pumped (the odometer reading out in miles divided by the pump reading out in gallons; i.e. miles per gallon)

/sarcasm off

Thanks for the numbers. I am not saddened any longer. This whole thing is hilarious.

Wow. Math 101! :p

I'm amazed this is a gas mileage thread with something NEW in it...

Anyway, I don't calculate it - waste of time doing that for a sports car.

Wow. Math 101! :p

I'm amazed this is a gas mileage thread with something NEW in it...

Anyway, I don't calculate it - waste of time doing that for a sports car.


I am not understanding you. Can you put some numbers next to your steps?

Okay lets see if this helps:

1. Fill your tank when the pump clicks off pull out the nozzle , do not top off.
2. reset at least ONE of the trip odometers and remember which one it is.
If you have a hard time remembering or just not sure, reset BOTH trip
odometers to 0.0

3. drive the car until you need to put fuel in it. I usually fill up around 200 - 230
miles. Let's take my last fill up at 224.7 miles

4. Fill the tank and when the pump clicks off pull out the nozzle, do not top off.

5. take the number of gallons just put in (in this case) My car took 12.3 gallons

6. divide 224.7 by 12.3 (224.7 / 12.3) = 18.26892 MPG

7. Reset trip odometer back to 0.0 before driving away

Okay lets see if this helps:

1. Fill your tank when the pump clicks off pull out the nozzle , do not top off.
2. reset at least ONE of the trip odometers and remember which one it is.
If you have a hard time remembering or just not sure, reset BOTH trip
odometers to 0.0

3. drive the car until you need to put fuel in it. I usually fill up around 200 - 230
miles. Let's take my last fill up at 224.7 miles

4. Fill the tank and when the pump clicks off pull out the nozzle, do not top off.

5. take the number of gallons just put in (in this case) My car took 12.3 gallons

6. divide 224.7 by 12.3 (224.7 / 12.3) = 18.26892 MPG

7. Reset trip odometer back to 0.0 before driving away


We need more steps. Can you subdivide the 7 steps you have into at least 15 or 20?

LOL, is it this hard to calc the fuel economy in a car? LOL

Miles driven / gallons added (at next fill up) = MPG

Now...explain gravity, and that if a tree falls in the woods...or beaver...LOL

True, it borders on laughable , however it appears some people are really NOT sure how to calculate MPG. With the HUGE range of MPGs reported (from 10 mpg to 24 mpg) it might just be possible some people ARE calculating it incorrectly. Hopefully this thread can help.

True, it borders on laughable , however it appears some people are really NOT sure how to calculate MPG. With the HUGE range of MPGs reported (from 10 mpg to 24 mpg) it might just be possible some people ARE calculating it incorrectly. Hopefully this thread can help.
Exactly... there are many people on the board that don't understand this process apparently. And Lord knows we don't want Tyrell to be saddened any further :rolleyes:

True, it borders on laughable , however it appears some people are really NOT sure how to calculate MPG. With the HUGE range of MPGs reported (from 10 mpg to 24 mpg) it might just be possible some people ARE calculating it incorrectly.
Yeah, that elementary school math stuff is hard...I wonder if they paid $40,000 for their cars because they calculated tax and interest wrong

this is fun and all but since there is already another thread that is a combination of 2 other threads on this exact same topic (both of which were posted in the same week) i am moving this one and then merging it with the other combined thread in tech.

Exactly... there are many people on the board that don't understand this process apparently. And Lord knows we don't want Tyrell to be saddened any further :rolleyes:

This whole thread was hilarious from the beginning. I guess if you don't put face icons, people think you're absolutely serious and/or saddened.