aussie77

Seeing posts popping up about the mpg issue for people, but what little information we have is scattered to the winds.

So, here is an attempt to gather it all in one place so we can maybe figure out what is going on. To that end, please post the following info if you have an RX-8:

1) Build date (if you know it), and whether or not it was held up at port

2) Miles on car. E.g I currently have 970 miles on my car.

3) MPG information. If you have a tank-by-tank breakdown that is perfect. Real, calculated data only please. No guestimations, or "220 miles per tank". Only the real deal, fill up at the station to full, miles driven/gas to fillup.

4) City/Driving ratio (estimated).

5) Driving Habits. What rpm do you typically shift, how hard do you accellerate normally.

Please help out and contribute what real information you have. My mpg is ok but not great, but some people out there right now are having major problems and it would be great to figure out for them maybe what is going wrong.

aussie77

Figured I would get the ball rolling.

1) Build date currently unknown, but bought the car in late august. Will have to check for port campaign and build date later.

2) Currently 970 miles on the car.

3) Three measured tanks so far:

a: 17.9 mpg
b: 16.1 mpg
c: 16.7 mpg

4) Probably about 70/30 city/highway. City driving however involves LOTS of time at idle. My 3 mile commute to work takes me 15-20 minutes, sometimes longer.

5) Driving habits: Typically shift between 3500 and 4000 rpm. On highway normally cruise about 80 mph in 6th.

mikeb

I dont think this is going to work

khoney

1) Built: 5/30/03, Delivered 7/22/03 (held at port)

2) 2600 Miles.

3) Latest 7 tanks with MPG and octane
18.3 93
18.46 89
19.3 89
19.3 89
18.75 93
18.3 93
19.4 89

4) 50/50 hwy/city

5) Driving Habits - driving to have fun with it - High RPM shifts whenever possible.

aussie77

So help me out here mikeb! Thanks for posting khoney.

akrx8

2nd allocation,built in july.when new only 17 mpg 50/50.4200 miles now and very constint 20.5 mpg on last 4 tanks.same driving habits.

mikeb

I'm not trying to be rude but people did this to predict when the rx8's were coming in and it seemed their was no logic behind it.

LesPaul

Delivered 8/14
989 miles
6 Speed
60% City
"spirited" driving
15.25 mpg

Hayseed

Don't know build date, but early VIN: ***0804
Mileage: 3050
MPG: never under 20, never over 21
C/H: 30/70
Typically shift at 3500-4000, 80+ mph on highway.

What I don't fathom is the radical difference some people are getting. I can't help but suspect they are not calculating properly. Perhaps they're fillin up when only 1/4 tank down? Doesn't make sense.

Speed Racer

Delivered with first allocation on 7/16
7100 miles
Track MPG: 102mi/13.581gal=7.5MPG
City MPG: 220mi/12.781gal=17.2MPG
HWY (80MPH w/ cruise control) MPG: 223mi/11.302gal=19.7MPG

With normal mixed driving I see between 16-18MPG and on all highway cruising I see 19-24MPG. Then there are the 7.5-7.8MPG track days that just prove that the harder you work the engine the more the MPG suffers but you also have a lot more fun! :D

RX-Nut

Delivered 7-11
2741 mi

Longest before fuel light.. 262 mi
usually averaging about before fuel light: 227 mi
My guesstimate for MPG avg is about 18.4
typical shifting: 3500rpm
usually driving at a smidge under 70mph
close to redline maybe 7% of the driving time
65% city 35% hway

You know what I cant seem to swallow.. is how a 5.7L V8 LS1 Corvette can have an MPG rating of 19/28 when we're here with our puny 1.3L - 2 Rotor at 18/24 (but what seems more like 15/19).

How many Corvette owners out there wanna speak MPG?

theedge

Hey there,

Build Date: 7/21/03 (bought off lot but had the build date/recall sheet pulled while I was there, and before I bought)

60/40 highway to city

800 miles on odometer

70/20/10 normal driving/harder driving/******* it

last tank 20.91 miles to the gallon

hope this helps

PS - Have gotten 290 miles on a tank without fuel light coming on

ptiemann

I cannot speak about the Corvette but my previous 3.8L V6 Firebird was advertised as 19/29 and I indeed got ~26, or with my gf driving 29 ;-)

We have to face it.. rotary means inefficient fuel usage. That's what we pay for getting a small and light engine.

Here my data:

City/ Highway: 20/ 80

Shifting around 4000 rpm, but occasionally hitting 6000-7000

1. fill with 87-gas from dealer: 17.2 mpg
2nd - 91 gas: 18.2 mpg
3rd - 91 gas: 18.3 mpg

Odo: 800 miles

At least it goes up ;-)

350 Formula

I have a 5.7 Firebird Formula. The reason it can get those number on the EPA test is you can drive the car and not exceed 2,000 RPM. With a bit of granny, leaving the light the car shifts at about 1800. It drives 32 mph per 1000 rpm in top gear, so you can be doing the speed limit at about 2,000. BUT, give it the gas and it drinks!! I get about 14 to 15 city driving because I am not a granny.

MikeH

Mileage Log
2004 Mazda RX-8
After Breakin Period
Totals
Miles 733.7 Avg MPG 19.4033
Gallons 37.237 Avg Cost/Gal 1.57397
Cost 58.61

Date Odometer Gallons Cost Miles MPG Cost P G Octane Notes
2-Sep 1638 4.817 $8.38 88.1 18.29 $1.74 91 50% city / 50% highway Cruz - Air
6-Sep 1727 4.5 $7.20 86.6 19.24 $1.60 87 50% city / 50% highway Cruz - Air
11-Sep 1814 8.112 $12.97 162.1 19.98 $1.60 87 50% city / 50% highway Cruz - Air
17-Sep 1976 5.779 $9.13 95.6 16.54 $1.58 87 100% city - Air
20-Sep 2163 8.127 $12.67 187 23.01 $1.56 87 50% city / 50% highway Cruz - Air
24-Sep 2277 5.902 $8.26 114.3 19.36 $1.40 87 75% city / 25% highway Cruz - Air

Here is my Sept. Log for Gas mileage.
6 speed GT shift about 4000rpm when I am good, 6000rpm not so good (30% of time.)
Increase of 3-4 miles per Gallon since last month using Premium fuel.
Love my ride.

ptiemann

I'm mostly on freeways, doing 90 mph every day, and hitting the breaks / re-accelerating .. just too many cops .. AND getting 26 mpg in the 3.8l V6.
Definitely not granny-driving.

I have to add to my RX-8 numbers (18 mpg) that I was stuck in traffic several times.. in hell of a commute all the way through Silicon Valley.

-Peter