Spork,

The difference can be much more than a few hundred.

Again, it's $500 per 10K miles with 15MPG vs 20 MPG and $1000 per 10K miles with 12 MPG vs 20 MPG (at $3 gas).

For those of us with the more guzzling cars, we are paying $5000-10,000 more than other RX8 owners for every 100K miles! That's insane.

vs. 25 MPG the numbers are $800/$1300
vs. 30 MPG the numbers are $1000/$1500... i.e. the 12 MPG versions of this car cost $15K more per 100K miles than a 30 MPG car in gas alone!!!... If we don't think that'll affect resale values in the years to come as more fuel efficient cars hit the market, we're in denial.

Plus oil hit a new high this morning of $57.XX per barrel. You know what that means? $3 premium will be here soon. It could be even worse than that in the years we own/lease this car if oil continues to climb as expected.

This car is awesome in every other way, but the cost of ownership is significantly higher for those of us with the more thirsty engines compared to those avging 20 MPG. That sux!

I hate to harp on this issue, but people need to understand the TRUE cost of fuel consumption before they beat us up for complaining... especially those on the ivory tower getting 20 MPG in their RX8's!

 

You sound like someone who puts a lot of miles on a car. I have 3 cars, 2 motorcycles, and truck to split the miles up. So if I get an 8 I will not put 10k on it in a year. So if I get 12mpg I will not be happy, but I will not be out "that much" anyway. The average driver is probably 10-12k per year. So that it really is not that big a deal. If you put 20k-30k or more per year on a car, you really should be in a Prius or something else.

Folks also are not going to be doing these high miles driving in a year unless they are using their 8s as taxis or messegner/delivery service duty. So that would mean long high speed comutes on long trips, which should return a lot better than around town MPG figures.

Like I said, without knowing how each person drives and how much of their "around town" driving is done stopped, crawling, or zooming on the freeway I don't think you can compare your numbers with theirs.

Fill your 8 up at a station next to a flat interstate during a time with little traffic or roadwork, then get on, get to 6th gear, and set the cruise of 65mph or so and leave it. Drive for 200-250 miles, then get off and fill up again. Calculate your MPG. How did you do? If your mileage is terrible VS what others are reporting for highway then something is indeed "wrong" with your 8. To get close to EPA numbers you would have to set your cruise at 48mph, which would get you run over around here :D

Dennis

 

I have the same problem with this advice as I do with those who say "They put in a new engine and my MPG is the same."

WTF is another whole car, or another engine, going to accomplish? Yeah, that new ashtray, new upholstery, new rotors, new output shaft REALLY affects the fuel/air ratio

There are a limited set of things that can account for the variance from a 10MPG car to a 25MPG car, everything else being equal (same gas, same driving conditions, same transmission type, etc.) Those are:

• Air filter
• MAF sensor
• O2 sensors
• Fuel injectors
• Fuel pump(s)
• Spark plugs
• Catalyst
• ECU/PCM/engine computer, whatever you want to call it.

These are the same for all modern cars, not just the RX-8. If I had a 10 - 15MPG RX-8, I'd try too make a deal with the service manager: Replace all of these things. For the computer, it needs to be REPLACED with the latest (not old stock) fresh one from the manufacturer, not just 'flashed'. We don't know that flashing the computer updates all of it's algorithms, just the software part that's designed to be upgraded. So, replacing may be better than flashing an old one. If replacing all of these things solves the problem (which I'm sure it would), then Mazda should foot the bill. If not, then I'll pay for my own wild goose chase.

I can't believe that with the close manufacturing tolerances of the rotary engine and the transmission that there can be enough mechanical friction differences to account for the fuel economy variations. It has to be in the fuel-delivery system somewhere.

 

Live 50 miles from work.
100 miles/day round-trip, house-work-house
500 miles/week
over 2000 miles/month
25000 miles/year
...plus normal life stuff during the week
...plus making that commute on weekends when necessary
...plus travelling for weekend recreational stuff
= over 30k miles/year.

Currently get 24-ish, occasional 22, occasional 25, in a VW GTI VR6. Yes I'm worried about getting an RX-8 for the fuel economy, but I'm not in diesel/Prius territory with my economy as it is now.

 

I don't know anyone who has had the engine changed due to milage issues.
The service manager can not change parts and be reinbursed under warranty unless they get codes that determine that a part is defective. That means I would have to pay for all that myself to resolve the issue.
By the way. I get the same 11mpg in town no matter how I drive the car. Fast-slow-hi rev-lowrev-granma in 5th and 6th. Its seems to make little difference at all. On the hi-way I get 16.

 

Unless you are zooming in on I-75 or something, I would say you need something other than an 8 If you were getting 15mpg on your commute then your are going to be realy unhappy unless you move closer to work or work closer to home.

Commuting is boring anyway, you could get an Echo or Civic or something to rack the miles up on and just drive your new 8 on Fridays and weekends or something...

Dennis

 

Latest attempt at improving fuel economy... minimal throttle, no worries with revs.

We'll see if running more than one injector, but less punch per each gets better economy in this fine car. Maybe that's your little secret all of you with 20+ MPG.

I thought it would be annoying, but honestly, it's funner than "grandma style." In city traffic it's actually not bad at all considering there's always some foolio getting in the way anyway and once you get the car to 3K+ rpms, she's so fun when you need a little punch here and there between traffic.

Needle seems to be running a little slower, but I'm still a day or so from empty.

I'll keep you posted.

BTW, I've been driving manual for a long time, but never had to play games like this. Then again, I've never had a sweeter ride. Not even close.

 

try keeping the highway driving to 63-65mph and report back... I think thats the sweet spot on my car.

also try getting a dyno run, or maybe even some kind of piggyback or canscan to log A/F ratio under different conditions

 

My take on mileage - all prices C$.

1 litre of gas = $0.89
1 litre of milk = $1.89
1 litre of beer = $2.08
1 litre of vodka = $40.00
1 litre of cologne = $466.00
10 kms of driving at 6000 rpm = priceless

 

I say spend $1000 and get a canzoomer/emange + canscan device and lean the car out a bit. with that kind of mpg your probably much richer than the avg 8. And if the mpg doesn't improve at least you can pick up some more hp

 

I commute 45 miles one-way in Los Angeles freeway traffic (405-S to be precise) to get to work. Now if you're familiar at all with L.A. to OC traffic, you will feel my pain. I get horrible gas mileage. Factoring in the non-work driving I do and I'm spending approx. $300/month on gas (and yes, I am being cheap and filling up with 87, sometimes 89).

It sucks, it sucks BAD but I love my 8 so what do I do? I grin and bear it. I just don't see the productivity of sitting down and trying to compute what my gas mileage would be under what conditions and if I drove a particular way. I want to drive my 8 the way that I want to drive it -- it was meant for me to drive it the way that I like driving it, which is occassionally rather crazy. I can't just bitch about the gas mileage every day or I'd kill myself or kill my 8.

Shitty gas mileage is a small price to pay for the enjoyment of my 8. I knew what I was getting into when I ponied up the cash and while I wish I could improve the mileage, at least I look good in my car, and really folks, isn't that what life is all about? I think the real goal should be to harass our government to lower the gas cost but that's a whole other thread.

Now I'm off to buy some strakes from Dennis.

 

I agree.. I'd usually rather not drive my 8 at all than drive it trying increase mpg. You just have to.. drive it... naturally...

 

Not happy?!?
On a good day,
I'm lucky if I get 10mpg (and I drive like an old blue haired lady).

 

10mpg? are you doing your calculus correctly?

the integral of the inverse of the gas consumed (in gallons) with respect to the change in position (in miles), where your constant equals zero

 

I'm a little happier today.

Drove to Sacramento gambling.

- 284 miles round trip in under 4 hours
- won some money
- no speeding tickets
- and 21.5 mpg

:D

And yes, I took the RX-8 today

 

Fuel consumption should improve slightly after break-in and in warmer weather. Despite higher oil prices and a weaker dollar, I don't see gas hitting $4/gallon here in the USA (expect it to fluctuate between $2.00 and $2.50). At $2.25 per gallon, 10k miles costs:

MPG Cost
20 $1125
19 $1184
18 $1250
17 $1323
16 $1406
15 $1500
14 $1607
13 $1730
12 $1875

I get 15-16 MPG. Compared to a 20 MPG vehicle, I'm spending ~$330 extra per 10k miles, which for me is $6 per week. The rotary is unquestionably thirsty, but given my driving style (95% in-town, short commute, mucho warm-up idling over Winter, lots of "energetic" driving), I wouldn't see better than 16-20 MPG with any piston vehicle with a comparable power-to-weight ratio.

If you end up getting only 12 MPG, I recommend that you track your fuel consumption, keep all of your receipts, and call MazdaUSA. If you can demonstrate that you consistently get such poor fuel economy, they should do something for you.

 

I don't know about your state but in California I paid $2.65 yesterday (Shell, 91 Octane)

Peter

 

The only number I can get is to the MAzda hotline. They always say they don't deal with technical issues and refer to the dealer. Thealers won't give out a Mazda contact.

 

It's $2.20-2.30 for 91 in my area. According to this, CA is the highest:I expect it to go up another ~$0.25 this Summer, and then drop again this Fall. Even in CA, I'd be surprised if 91 hit $4, though it might get close to $3. If it did hit $3 around here, I'd be spending an extra $437 per 10k miles instead of $328 vs 20 MPG (or an extra $8/week vs $6/week). To me, it's worth it (there are more powerful cars that get similar or even slightly better fuel economy, but none of them have the RX8's driving dynamics).

You should bring your gas receipts and a spreadsheet showing your fuel consumption trends to your local service department first. If they don't help you after a few visits, then file a complaint with MazdaUSA:

mazdausa.com > contact us > 1-800-222-5500

However, how do you drive? If you constantly keep it at 6000+ RPM and flogged, you can expect <12 MPG. I cruise at 2500-4000 and normally shift at 5000-7000, but I also have some fun on every drive, flogging it to redline/limiter probably 10-20 times each day (over an average of 26 miles per day). Again, with 95%+ in-town driving, I get 15-16 MPG.

 

I called that number three times. Total wasste of time. They call the dealership and that is it. They won't give you another number, have anyone call you back or do anything else.

 

I think that's how most people want their cars. 15-16 city when driving funwise. 18 if you want to grandma it. The problem is most people get 15-16 city grandma'ing it.

Ooog, gas costs in a few months is going to be ugly.

 

Hun???
Me no speak-um jibber-jabber....
100 miles / 10gal = 10mpg
My 7yo helped me with the Ancient Greek Ciphering.

 

Stop crying about the gas mileage when you totally forget about the REAL COST of owning an RX-8!!! The cost difference between all competitive car is negligible. Assumed you drive 12,000 miles/year, with fuel cost at $2.25/gallon, insurance based on http://auto.consumerguide.com/, and mpg based on Consumer Reports average... this is your REAL COST.

 

Actually, I think the majority of RX8 owners get 15-16 city without feather-footing it, but there are a some who are getting worse and some who are getting better. I've never tried to see what I could get by *always* keeping it under 3200 RPM because even if I hit 20 MPG, I sure as hell am not driving my RX8 that way all the time :-)

 

A couple of weeks back we drove to the desert, and being a popular drive, we spent most of the day in one train of vehicles or the other. It was a pleasant drive since through most of the drive we were 5/10 mph over the limit, but there was not much hard acceleration. As a result, I spent a good part of the day at or under 3500 rpm. For the first time I got just over 20mpg on that tank! My mileage across tanks has been 14.3, 15.2, 15.5, 15.3, 14.0, 14.4, 14.2, 15.4, 14.3, 15.2, 15.6, 20.1, 14.8.

You can see I had to make up for the slow weekend drive. :-)