Does this seem correct? [Gas Fill Up]
 

I wanted to know how much I'm going to be spending on gas if I do end up getting this RX-8 so I used an online calculator of sorts to help me out.

Weekly Usage
Commuting [per day]: 24.6mi
Number of Commute Days: 5

Other [per day]: 54.6mi
Number of Days: 2

The "other" calculated is the drive to my boyfriend's house which is about thirty minutes from where I live. I don't include the short trips like to stores or picking up my brother since they are local.


Other Values
Tank Size [gallons]: 15.9
Car Miles per Gallon: 20 [I estimated since 90% of my driving is highway]
Current Gas Cost [per gallon]: $3.79


Weekly Calculation Results
Miles: 232.2
Gasoline Consumption: 11.61
Fill Ups: 0.73
Cost: $44




I am certainly no math wiz, I've always struggled with it. I just expected it to be more perhaps? I copied the above from the website [http://www.getgasfacts.com/gascalculator.php] because it wouldn't let me screenshot it.

Use that as your "at least this much" number.

Using that calculator, I should be around $30 a week in gas, but I actually am at around $50-60, largely because I actually do more driving than commute + other specific trips, and also because I get too big of a grin on my face driving in a manner which happens to be at less than optimum efficiency :)

I was expecting somewhere around $60 when I first started reading up on this site; but I just got a new job which is closer to home and my college work is online so I won't be doing too much driving. I just didn't want to think I'll be spending $40 a week when I'll really be spending more, haha.
Thanks for replying, it was helpful :)

I'm in the same boat as RIWWP...when I got mine I drove much more than expected because of the grin factor. Don't forget to calculate that. I've had mine for 8 months now and I'm approaching doubling the mileage from when I bought it.
Bought at 15,500...currently at 28,andchange. My previous car I drove about 8,000/year!

Dang, well I try not to drive a lot now because I hate wasting gas. When I do drive it I will have some fun :) I live far from the city [hence the long drives] so I'm surrounded by nice curvy roads on the way to local places.

It doesn't matter to your overall numbers, but you'll be lucky to cram 15.9 gallons into it. That would be running it bone dry..........which you should never do. Count on right around 13 gallons.

I don't understand why it would be 13gal?

Tank is 15.9, but light comes on at 2.8 gallons remaining (13.1 empty). Assuming you are a normal human being, you will usually fill up around then. Doesn't change the dollar figure, just the "fillups per week" figure :)

Correct, and some would tell you that it keeps you from also sucking crap off the bottom of the tank all the time and possibly causing other issues.........besides having to thumb a ride cause you ran outta gas. :)

I want to try and keep it refueled at half a tank each time if possible for me. Maybe a quarter. I just don't know how fast it will suck the gas right now until I drive it.

Oh & thanks for explaining :)

I've seen a few high mileage DD gas tank pictures. I really don't think there is actually much "crap" (if any) in the bottom of the tanks.

The bigger reason not to go too close to empty (for any car) is that the gas is used to cool the fuel pump, and going empty can kill it. Not 100% of the time, but it's possible. Plus the chance that you will be at full throttle when the fuel pump hiccups, which generates a sudden lean spike in the engine and boom, there goes your engine. It's possible in any car, though the penalties for doing it in a rotary are far more severe, and any time you are under 1/4th of a tank, it's something to watch for.

I say under 1/4th, because our tank isn't flat. It has a hump dividing the two sides, and at ~1/4th of a tank left, the gas is split between the two sides. We only have the pickup on one side, and a small siphon tube runs between them to try to keep them balanced. But, it's been known to happen that a high G left hand turn pushed the fuel to the right side and starved the fuel pump, shutting off the engine.

http://www.ft86club.com/forums/attac...3&d=1323307033
http://www.grandamadventure.com/rx8%20FuelTank.jpg

It is not my intention to discourage your purchase, but if you are concerned about fuel costs, then I would not buy an 8. They are not cheap cars to operate and fuel is only one aspect of related costs. If you are on a tight budget, a different type of vehicle may be in order? I "assumed" fuel cost was a concern since you took the time to do online research and then post your findings here. I could be wrong of course?

Sounds like you'll be filling up about once a week.

the short trips to stores and picking up your brother are killers on gas mileage. they MUST be included when doing your figuring.

20mpg is way off. that would be your AT BEST. not your AT LEAST. AT LEAST will be @15mpg depending on how many of those store and brother pickups you do.

all driving is "city". it doesnt matter where you do the driving all regular driving is "city".

"Highway" is long vacation driving i.e. , you fill up the car, get right on the highway and drive until the tank is empty at normal highway speed limit speeds then get off and refill.

I'm not concerned, I was just curious :) I like to know all aspects of a car before I purchase and how much things will cost me just because I'm mindful of my money. I like to have things calculated and figured out before hand about everything I purchase :p


& thanks for the information!

I agree with Zoom. It's better to be conservative on your MPG. I live close to where I work and on average I get 16-17 mpg's even with frequent highway driving. The only time I get MPG's in the 20's is during long trips on the freeway. +1 to what everyone said about the fun factor...if you get an 8 you'll definitely want to drive it and drive it hard.

Well, a couple lower than my estimate isn't too bad for me :p I still am going to try my best to get one of these, now it's just up to finding the perfect one!

I like how you research first before you buy it. Most people don't do that, they just buy it for looks...like me. lol

Oh yes, I've done some intense research haha. I'm reading everything I can find about how to run the car, how to maintain it, everything. I just need to get more information about how the mechanical parts work [I learn better by seeing and example so it's kind of hard for that right now]. I just want to make sure I'm prepared before I make such a big purchase :)

Good on you.

As an 8 owner who did similar calculations before buying, I understand.

I think that your estimates are ok - assuming you REALLY get 90% highway. That would mean you stay on the highway for 1-2 hours of driving at a time, with very little side roads to and from the highway. My RX8 makes a huge difference in fuel mileage when driven on highway and off. I get very regularly 300km per tank of "mixed" driving. If I can get a couple hours of highway driving in there, it easily adds 50-60+ km to the tank range.

When buying an 8, budget for your gas - then double it. Fortunately, you can also think about how much fun a winding road will be - and the 8 will double THAT for you. It all works out in the end.

Have fun shopping!

Thank you :)

My average was 15mpg, and 80% of my driving was highway. I am in california though so the traffic is insane at times. This was also with a brand new engine with brand new coils, plugs etc. I, like you, was expecting 20mpg when I bought the car. The best mpg I got was around 18 on one tank.

If you look at my fuelly you'll see what to expect lol
http://www.fuelly.com/driver/Rommel/rx8

Can you tell when I was highway driving on the graph? LOL
I took a recent trip from GA to SC...

Less is fine with me, I was just trying to guess :)
Thanks for adding your input on it; it helped me figure out how much I'm going to be spending