rx8wannahave

I was just saying, at least I didn't instult the guy or get mean about it like some of our...less friendly friends here, lol.

Trust me, if I was getting 12.5mpg I'd be all over Mazda about it.

BunnyGirl

I don't know for sure which is actually "better," just that the dealers were recommending them in that order. A really long time ago there was a Mazda dealer next to a 76 station and they kept saying their gas was the best. However, nearly every time my mom gets 76 she starts having issues with the engine running rough and has to do fuel treatments to fix a presumed water in the gas problem, which after these treatments and using up the tank plus a second one and it is better.

Cooder

This question suggests you don't know what is relevant. If you're calculating MPG correctly, you wouldn't be worried about how many gallons others are filling up with.

Tell us exactly how you are calculating your MPG.

The tank is 15.9 gallons. My light seems to go on at right about 13.0 gallons used.

jisoo26

I'm on 200 miles right now with 1/4 tank to go. This is still my first tank of gas on this car (bought brand new a couple weeks ago)

BunnyGirl

According to the 2005 info I had printed out from Costco it says the cruising range is 220 miles city and 280 miles highway. I don't know if this reflects how far you can drive before your tank is completely empty or if this is the range when your light comes on. It didn't say, but supposedly that is how far a "tank" of gas is supposed to take you.

Raptor75

You need to read what you commenting on more carefully. He said he was getting x-miles per tank full. I asked him what he counts as a tank full. The simple math will give you a useful approximation of his mpg.

I’m waiting a few more thankful before resuming this thread to obtain my exact mileage and useful averages.

frequentflyer

In case it's useful, here are my stats as of 5000 miles on the odometer (this is a 2005 6-speed with the R flash--or actually, it might be called E in the 2005's. It's the flash that came after the hot gas tank problem.):

1) Never less than 17 MPG, and never more than 22 MPG.

2) Typical driving (40% city/60% hwy) is right about 19 MPG. I use mid-grade gas, usually from Diamond Shamrock.

3) The 22 MPG included a lot of 6000 RPM driving at around 60 MPH in the Colorado mountains on 2-lane roads over high mountain passes. I have done multiple trips like this, and they all created my best mileage.

Yes, these MPG's are all calculated "correctly." But for those people who like gas guage readings, my guage is nearly linear at about 70 miles traveled per quarter tank consumed.

Now for my opinions: I absolutely don't believe the 3750 RPM magical number that a lot of people say you should stay below. In fact, it feels like the car is lugging anywhere below 3000 RPM, so if you tried to drive between, say 3200 and 3750, you wouldn't have much range!

Once the car is warmed up, I almost never shift below 5000 RPM (it's usually around 6000), and from 1st to 2nd it's often above 7000.

My break-in consisted of varying the RPMS a LOT, but keeping them "low"--below 7000 RPM (not below 4000 or something).

I take the car to around 8000 RPM at least once on nearly every drive.

My conclusions:

1) It's not the RPM's that kill you (unless you drive for long periods around 7000-9000 RPM). It's the idling that kills you.

2) My best mileage correlates with speed, not RPM. The speed was around 55-65 MPH, with very few stops (i.e., virtually no idling), but included significant high-revving (i.e., above 6000).

3) 12.5 MPG is way too low, unless possibly if you're doing a lot of idling, but I don't have much experience with that.

4) The RX-8 forum seems to peg the average MPG around 19 MPG, with some statistical outliers in the high 20's and in the low teens. The high 20's owners should be very thankful, and the low teens owners should complain loudly to Mazda.

jisoo26

Well I finished my first full tank a couple days ago. 238 miles on mixed driving (maybe 60/40 highway/city). 238/15.9 = about 15mpg. Seems like that's right around the average for everyone. (Then again I'm barely over 400 miles right now ). I'll be glad to get slightly better mileage once I put some more time on this thing. I love my 8 more everyday! *w00t*

wisconsinben

YES...the proper way to view this topic ^^^

JonsToy

Sorry, but the only time you use 15.9 gallons of gas, you end up stranded on the side of the road. Chances are, it took less than 15.9 gallons to refill your tank, and if you started with a completely full tank, you should divide the 238 miles you drove by the exact amount of gas you used to refill your tank. That will yield your correct mpg.

MPG 101!

RX8_GT

JonsToy:

Agreed - wish people would stop talking about miles per tank - a truly useless 'measurement'.

Only useful way to compare to full tank to full tank MPG measurement - best over several tankfuls.

BunnyGirl

Agreed. Please see my rant.

https://www.rx8club.com/showpost.php...3&postcount=19

jisoo26

Yes I know that, hence I wrote the phrase about 15 mpg . I went down to the empty light and then some. I don't think another few miles would affect that figure much. Exact amount of gas? What do you expect? For me to pull into the gas station and siphon out the remaining fuel with a tube for correct measurement? The way you present your comment makes you sound arrogant and uppity.

RichardK

I thought I'd posted in this, but I don't see it. Howell.

First 'tank' wasn't really a full tank - but it was quite telling. Following the 'be gentle, but not too gentle, and don't stick at the same revs for long periods' school of running in, my first drive was: Collect car in Leicester, fill up from the roughly 1/4 tank indicated (£42), get stuck in traffic for almost an hour crawling along, travel up M1 and A1 at normal UK motorway speeds (around 70-80mph) switching between 4th and 5th a fair bit, but not exceeding 5,000rpm.

Pulled in to fill up at Washington services - 184 miles since filling the car - and it took £29ish; when calculated, it was returning 27mpg. This has dropped to about 22mpg around here, using more of the power but still not driving as I normally would (3,000rpm, whichever gear is needed for the speed I want - 5 speed is higher geared on paper so 70=3,000 rpm in the 190).

Richard

RX-Aight

No offence, but I wouldn't really consider your original post much of a contribution, constructive or otherwise.

djgiron

No you werent supposed to syphon out the remaining gas, but if you notice, when you are refilling the tank, there is a meter on the pump that tell you how much you are putting back in, which coincidentally is also the amount you just emptied on your 238 miles drive . . . so that number would be the number you divide into the 238 to get your miles per gallon. Do that over 3 or so tanks and you get a pretty good idea of your average MPG.

Spin9k

.....And you would be wrong... totally wrong on your calculation.....by a bunch! Let's say you left 2 gallons in the tank...on a fill thats 14% off (15.9-13.9=2/15.9=.14)

Taking an example:

238 miles / 15.9 = 14.97 (surprise! - what you got - a nice low WRONG mpg)
238 miles / 13.9 = 17.12 actual MPG

quite a difference... and it is simply because of the small tank in the RX-8 causes even minor mis-calculation to have big effects.

jisoo26 people here ARE trying to help ... why not listen and perhaps believe if enough tell you the same thing? Math done right IS knowledge! Use the knowledge.

BunnyGirl

Just look to see how much gas you bought when you filled up (the pump will say, generally below the price window). Most people seem to get 13-something gallons when they fill up on here, which I believe the light comes on with 13 gallons used.

So, if you have a receipt you can check that and recalculate and get the actual MPG. If not, just do it that way when you get your next tank. It is an accurate calculation that way instead of a rough estimate.