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How to get BEST MPG on Rx8 (~20-22mpg)

Old Oct 31, 2008 | 01:57 PM
  #51  
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From: Hunterdon County
Originally Posted by Learjet_Pilot
My complaint to the dealer was rough idle. I am still within my 12/12 warranty.
Thanks, but what is the 12/12 warranty?
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Old Nov 1, 2008 | 02:57 AM
  #52  
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From: Love Field.
Sorry Bro. Still within 12 months and 12,000 miles. If I think a wiper blade is a little flaky, I get it replaced. (For another month and 1/2).

And why is topping off bad for the evap system. Somebody school me on that.
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Old Nov 1, 2008 | 06:43 AM
  #53  
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From: Hunterdon County
Originally Posted by Learjet_Pilot
Sorry Bro. Still within 12 months and 12,000 miles. If I think a wiper blade is a little flaky, I get it replaced. (For another month and 1/2).

And why is topping off bad for the evap system. Somebody school me on that.
Hmm ... I didn't realize Mazda gives better replacement warranty coverage during the first 12 months.

I'm no expert, but what I've heard about overfilling the gas tank is that if gas (and not just fumes) backs up into the charcoal canister enough times, it can degrade the charcoal, cause it to break up into small bits, which can then lodge in a valve in the evaporative system, causing it to stick open. Not sure of that, just repeating what I've heard from people who at least seem to know more than me.
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Old Nov 1, 2008 | 08:34 PM
  #54  
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Originally Posted by robrecht
is nearly impossible to fill the gas tank completely and it isn't good for the evaporative system anyway so it's hard and inadvisable to try to get overly exact figures so I think there's at least a 2 mpg margin of error in most measurements.
I would hope most people simply divide the gallons when they fill up by the miles since they last filled up. If you're dividing by the theoretical capacity of the tank, you're going to be way off. Isn't that how most people do it?
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Old Nov 1, 2008 | 08:47 PM
  #55  
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From: Hunterdon County
Originally Posted by GTConversion
I would hope most people simply divide the gallons when they fill up by the miles since they last filled up. If you're dividing by the theoretical capacity of the tank, you're going to be way off. Isn't that how most people do it?
Of course. No one said anything about using the theoretical capacity of the tank. But I'm sure you also realize that simply dividing the gallons when you fill up will also always introduce some error since the tank will not be filled up to exactly the same point each time, hence what I said about a margin of error.
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Old Nov 2, 2008 | 07:17 AM
  #56  
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From: Love Field.
You can easily put more than a gallon of gas into the tank after the first "click" of the gas pump. Your MPGs would then vary wildly. My measurements are done by filling until the gas is visible in the filler, but given that charcoal canister issue, I'm gonna stop doing that.
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Old Nov 2, 2008 | 08:53 AM
  #57  
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From: Boosted...
You get better mileage in the RX8 by driving south, because you are driving downhill.....
Just look on any map.
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Old Nov 3, 2008 | 11:14 AM
  #58  
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how much can the tank hold at maximum capacity?!?! i know its not 15.9 or whatever it has to be more.
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Old Nov 3, 2008 | 11:40 AM
  #59  
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From: Under the Dumbarton Bridge
Originally Posted by Rote8
You get better mileage in the RX8 by driving south, because you are driving downhill.....
Just look on any map.
Lies! the earth is fatter at the equator. Drive south and you're always heading uphill!

Unless you're in the southern hemisphere....
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Old Nov 3, 2008 | 11:42 AM
  #60  
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You get the best mileage with an RX-8 by towing it with a Vespa.
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Old Nov 3, 2008 | 12:45 PM
  #61  
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From: Lafayette, LA
Originally Posted by always.anthony
how much can the tank hold at maximum capacity?!?! i know its not 15.9 or whatever it has to be more.
I thought it was 60 liters, but I also thought that it was 16.9 gallons. And 60 liters is only 15.9 gallons so IDK
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Old Nov 3, 2008 | 02:36 PM
  #62  
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Originally Posted by greg985
I thought it was 60 liters, but I also thought that it was 16.9 gallons. And 60 liters is only 15.9 gallons so IDK
and is maximum capacity until the nozzle clicks, or filling it some more e.g. till you can see the gasoline almost overflow
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Old Nov 3, 2008 | 02:42 PM
  #63  
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From: Fort Lauderdale, Florida
I didn't buy my 8 to worry about gas mileage.. longest I've done on 1 tank though was 324 miles with one last little bar before the E.. 100% highway driving in 6th gear at 4k RPMs I believe.
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Old Nov 5, 2008 | 05:00 PM
  #64  
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there is a simple answer.. fill up and record the mileage you have.. then at half a tank add another $10 without recording it.. When you tally it all up on paper you'll hit like 30mpg or more.. baller...

anyway in the real world keep it under 4000 use premium good not bp **** or arco.

buy all lightweight parts (flywheel exhaust pulleys) and use the cruise control often..

Good luck gentlemen!
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Old Feb 8, 2013 | 07:08 PM
  #65  
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From: SK, Canada
Mpg???

Did you guys really buy these 8s for the mileage?? Come on, these cars are meant to drive hard! These are thoroughbreds, and as such will eat like their horse counterparts... a lot!!

Mine is still in storage until the much awaited spring and so I take the time to make her shine inside and out... I'll line up a new set of skins for the back as well ... haven't any idea what happened to the originals, heh heh!

MPG, is a slight concern, but only if it drops to lows, then its telling me somethings wrong... until then boyz 'n girlz I'm doing what these are meant to do:

ZOOM ZOOM!!!!
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Old Feb 8, 2013 | 07:10 PM
  #66  
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Er, dude, this thread is OVER FOUR YEARS OLD!!!!!

I think they'll have found out the fuel consumption by now......
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Old Feb 9, 2013 | 07:41 AM
  #67  
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Dont start the car, excellent MPG
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Old Feb 12, 2013 | 02:14 PM
  #68  
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Originally Posted by always.anthony
i don't understand the how pushing more rpms will increase mpg.

best mpg is best speed to rpm ratio.

go as fast as you can, as close to 800 rpms (idle)
I disagree. I seem to get more milage at 3500+ rpm.

But during wintertime, my mileage drops from 360-380 km to 250-300 km. Tire size is by the book. Has been like that for 6 years...

Kaido
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Old Feb 12, 2013 | 09:02 PM
  #69  
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You wanna get better MPG on any car? Drive like you have no brakes.
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Old Feb 13, 2013 | 04:11 AM
  #70  
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From: NZ Brahhhhh
I don't give a **** about MPG.

If I did, I would sell up and buy a Prius

This thread is full of fail
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Old Feb 13, 2013 | 08:45 PM
  #71  
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Who cares about mpg, i'm rich, i could afford gas, no matter how high they get...lmfao
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Old Mar 8, 2013 | 12:03 AM
  #72  
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Mpg sucks...

My '04 has been getting an average of 15 mpg lately. What kind of air filter and air intake should I buy to raise the mpg at least a little? Please post websites where I can buy one. Also, will they EVER come out with a performance chip!? that would be the highlight of my life! Much appreciated!
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Old Mar 8, 2013 | 03:19 AM
  #73  
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From: NZ Brahhhhh
Originally Posted by zoomzoomlover
My '04 has been getting an average of 15 mpg lately. What kind of air filter and air intake should I buy to raise the mpg at least a little? Please post websites where I can buy one. Also, will they EVER come out with a performance chip!? that would be the highlight of my life! Much appreciated!
um NO!!!!!!!!!!!!!
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Old Mar 8, 2013 | 07:58 AM
  #74  
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Originally Posted by zoomzoomlover
My '04 has been getting an average of 15 mpg lately. What kind of air filter and air intake should I buy to raise the mpg at least a little? Please post websites where I can buy one. Also, will they EVER come out with a performance chip!? that would be the highlight of my life! Much appreciated!

You have some reading to do or you will be flamed (ridiculed) to death on this site. There is no "performance chip" that will actually do anything good for your RX-8.

Please read the following: https://www.rx8club.com/rx-8-discuss...thread-242295/

If you have questions and don't want someone to give you a hard time go here: https://www.rx8club.com/rx-8-discuss...llowed-208221/
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Old Mar 8, 2013 | 08:03 AM
  #75  
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From: Pacific Northwest
These two threads are a bit more accurate for his reading:
https://www.rx8club.com/rx-8-discuss...t-here-202454/
https://www.rx8club.com/rx-8-discuss...rx-8-a-233937/

Specifically on the 2nd link:
- Intakes and filters are addressed in post 2
- ECU chips are addressed in posts 2 and 3
- Gas mileage mods are addressed in post 10

The short answer is that 15mpg with 100% highway means something on your car has FAILED. You need to repair the problem.

15mpg with 100% city is about normal, maybe a tad low.
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