I was wondering as all of you have also that I wish my 8 had like a 18 gallon fuel tank. Maybe Mazda was trying to save weight or simply did not have the room but has anyone considered sticking a bigger tank in there?

Currently we have a 15.9 gallon tank and our range (per the EVIL EPA…lol) :p

@15 gallons City = 270 Highway = 360 (with a variance per the window sticker of 225 to 420…just as a theoretical range)

It seems the average comes out to something more like:

City = 200
Highway = 300

I’m not into adding weight to the 8 but it would be GREAT to be able to put a 18 gallon tank in the car. The issues will be:

Limited space
New tank (you can’t build your own…lol) would probably have to be from another car for crash worthiness
Will the gas gauge work?

Removing a tank is pretty easy (sort of)thing to upgrade…drop the tank, add a new one…but I know it would be a little harder than that. I just know that if we had a bigger tank we all would be a lot happier. Heck, maybe fuel economy would not come up so much if we could drive longer distances before filing up.

I reach 250 miles on a tank of gas (so far) normally but I would love it if I could get another 25 miles in the city. That would take about 18 gallons, which is only another 2.1 gallons. Not much…but the space and effort needed might be too much.

Has anyone attempted to replace the tank or does anyone have a picture of the RX8 (X-Ray type) that shows you the engine installed, tranny, gas tank, suspension…etc…

I would love to see how tight it really is in that space. Or, am I just chasing after the pot of gold at the end of the rainbow?

 

Have you seen where the gas tank is in an RX-8? Tip - there isn't one tank, there's two, connected by crossover plumbing, one under each rear seat. You aren't going to drop a tank from anything else in there! Mazda pretty much filled the available space under the rear seats with the existing tanks - we're pretty much out of luck.

There used to be links to the Press Kit from the official introduction of the car that showed the fuel tank locations in cutaway drawings - a search might turn those up.

Regards,
Gordon

 

Looks pretty complex to me. See attached diagram.

 

Could a 5-10 gallon fuel cell be added to the trunk? It would need to be connected to the main tank and would need it’s own fuel fill door.

 

Why must you guys hurt me so fast...all I did was drive home and BAM, there goes another dream...LOL :p

Well...I want to see more, it's just 2.1 gallons...heck, at this point after reading the response and seeing the diagram...I'll settle for a gallon :D

 

I really need a cut-away picture of the 8, I need to go search.

Here is another thought...how about useing some of the "middle bar" I have no idea what to call it that runs between the seats. If I remember right...it is pretty much an empty space.

 

Something like this, Would not take up too much space in the trunk.

LINK

 

Yeah...something like that, but I wonder if we can save our limited space in the trunk and hide something like that some place other than the trunk?

I"m still dreaming...I know, but I can't give up so fast...

 

Well, I sent an email to a "custom" fuel tank builder asking them if they would make a customer fuel tank for the RX-8. They probably will laugh at me but I thought I would try at least.

 

Well, two emails...and no takers yet. I was told that our tank is made out of plastic?

Anyway, I think WE ALL would love a 18 gallon tank in our 8 (as long as it did not weigh more...heck...it might weigh less).

I'll keep looking...

 

am i the only one with a 14 gallon tank?

 

????????
Are you driving an RX8? Haha.

 

It's 15.9 BUT l the realistic amount is 14 gallons that takes me about 260 miles. The fuel gauge is WELL below E and I really would not feel comfortable driving around with the needle far below E. So 14 of the 15.9 tank is about the most I use.

 

Overall, I'm very happy with my 8, but if I could snap my fingers and change some things, the changes would include what you mention; bigger gas tank. Short of improving MPG by 3 or 4 MPG, two or three more gallons in the tank would make a signifcant difference in range.

1.3L

 

the most i've ever put in my tank is 15.1 gallons, and that was on a 'kramer-style' way below the E tank.

either way, im lucky to get 200 to the tank

 

The tunnel down the middle (and saddle part of the tank) is for the driveshaft and exhaust. You bought into RWD, remember?

 

thats not the problem
it wouldnt matter if we had a tanker hooked up
are cars suck on gas i hate the mpg in this gas guzzler
sorry for rant i just cant take it sometimes when it comes to what i get in gas

 

our 16 gallon tank is already HUGE...for a sports car...that is a lot of gas to lug around

eventhough our gas mileage is bad...instead of EXPENSIVE fuel tank add ons that probably wouldn't be safe and mess up the weight distribution...why not just carry a plastic tank with you and fill up if you are low

 

I know, I agree…I would love a 17-18 gallon tank. (and/or 2-4 more mpg). I think we all should find a place that makes (SAFE) & (LIGHTWEIGHT) fuel tanks and OVERLOAD them with emails wanting them to upgrade our tanks. I think they would have A LOT of 8 owners knocking on their door.

Gosh, I’m sorry man…how are you driving your 8? I get 250+ without a problem so far on my first 4 tanks. (I have 1100 miles on my car…give or take) Kramer style...LOL, I remember that one...LOL


Yeah, I thought that space was taken…just checking…LOL, I love RWD!!!

Naa, I think for a sports car the 8 get’s fair fuel economy. I have filled up 4 times and have never gone under 18.9mpg. Can that change…sure, but if we had a bigger tank our range would get A LOT BETTER!

I just want a bigger TANK!!! Just give me another 1.1 (to reach 17) and I would be happy, there has to be another 1.1 gallons...right....RIGHT....

 

Amen to that!

We're talkin' big bucks to have a custom tank (a few dozens, say) made for a minor gain in capacity. It wouldn't be worth the cost.

 

how about putting a flat tank in the trunk up against the back seats (5"Dx20"Wx15"H) tap into the true tank under the seats and fill up from the trunk lol.........you would need to see into the plastic tank in the trunk to tell you when to stop fillup, thats 1500sq inches of extra fuel capacity........whats that in gallons:p

 

I was at the Chicago Auto Show on Friday. They had eather a Ford GT or a Corvette, I forget which, cut down the middle. The gas tank was above the drive shaft . With the big tunnel running down the center of our car, it might be a good place for a custom tank. It would require some baffelling however to keep the fuel from flying forward under breaking.

 

Hey, since you did your oil holder mod and have the pass-through storage open, put a gallon tank there and thread a hose down to the main tank. Put a valve on it and it's a reserve tank!

 

You guys do know that gas tanks are illegal inside the car, right?
Even if you were able to add x number of gallons to the fuel tank, you mileage wouldn't remain the same on a full tank as you'd be adding a lot more weight to the car. So the improvement if possible would be minimal and we aren't even getting into the handling aspect of it.

 

Exactly- why the hell would you want to add even more weight to a sports car?? If anything, I'd rather the '8 were lighter.