Notices
RX-8 Discussion General discussion about the RX-8 that doesn't fit in one of the specialty forums.

Buyback for misquoted HP... what about the apparent missing MPG

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old 09-11-2003, 09:48 PM
  #26  
Senior Geek
 
RX8-TX's Avatar
 
Join Date: Aug 2003
Location: Richardson, TX
Posts: 1,005
Likes: 0
Received 0 Likes on 0 Posts
Originally posted by Skyline Maniac


The worst I have got in my G35C is something like 14mpg.... this is from driving hours after hours in only the first 2 gears in city traffic. The best I have gotten is on a long highway trip that gave me around 28mpg. (cruise control at 70mph up+down hills for hours) Those dreaded city travel averaging under 10mph is really killing me.
Kindda know what you mean. But this guys doesn't complaint....he bought his G knowing he was getting a 350Z in disguise (...possitive comment, alright??..Im not bashing anything)

And he's dealing with it. IN fact, he's been happy with the car so far...except for a few glitches that took him back to the dealer for a day or so (passenger power seat was somehow stuck, nothing major..)
Old 09-11-2003, 11:06 PM
  #27  
Registered User
 
Tweety-nator's Avatar
 
Join Date: Jul 2003
Posts: 49
Likes: 0
Received 0 Likes on 0 Posts
Originally posted by RX8-TX


Kindda know what you mean. But this guys doesn't complaint....he bought his G knowing he was getting a 350Z in disguise (...possitive comment, alright??..Im not bashing anything)

And he's dealing with it. IN fact, he's been happy with the car so far...except for a few glitches that took him back to the dealer for a day or so (passenger power seat was somehow stuck, nothing major..)
Hey, nothing wrong in saying that the G is a 350z in disguise... in my opinion thats a compliment. :D
Old 09-11-2003, 11:42 PM
  #28  
Registered User
 
Monster8's Avatar
 
Join Date: Sep 2003
Location: San Diego, CA
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
Re: Re: Buyback for misquoted HP... what about the apparent missing MPG

Originally posted by zoom44


hi Wankeler. the fuel efficiency rating is not mazda's it is the epa's. as for the allowable variance, check the window sicker, if you still have it, below the big bold numbers it show the range. i have my sticker in the car if you don't have yours, i will check it.

and no there wont be a buyback because they are not mazda's numbers
Just thought I'd chuck in my $.02 as my first post. The sticker says the range for city is 15-21 mpg and 20-28 for highway. That sounds consistent with what most people are getting, though granted we all fall on the bottom side of that range. I don't think there's been any misrepresentation about the economy. My '98 stratus claims it gets 28 mpg and even on a 2000 mile cross-country trip I never broke over 25. I think you'd have to really nurse any car to get the numbers they put on the sticker, but I'd like to hear if that's been everyone's experience with other vehicles.

And for the record my car (VIN 02196) has been getting a consistent 19mpg in mixed highway/city. My worst is 15 (pure city) and best was 23 (pure highway).
Old 09-12-2003, 12:24 AM
  #29  
Registered
 
newport8's Avatar
 
Join Date: Sep 2003
Location: Newport Beach, CA
Posts: 72
Likes: 0
Received 0 Likes on 0 Posts
Originally posted by Elara
Am I like the only person getting decent gas mileage from this car? 18-19 city, 25-26 highway. Yeah, the book was wrong. Books like that are ALWAYS wrong in places. Especially books made for marketing purposes.
Man, if I were guaranteed to get those mileage numbers, I would easily have bought an RX-8 already! I was just about to get one when I read about the widespread mpg problem, and it really made me hesitate.

By the way, Elara, is your RX-8 one of the first ones that were held up at port?
Old 09-12-2003, 09:46 AM
  #30  
Registered
 
rotarygod's Avatar
 
Join Date: Apr 2003
Location: Houston
Posts: 9,134
Likes: 0
Received 22 Likes on 21 Posts
It doesn't sound like most of you guys ever owned a naturally aspirated (or even turbo) rotary before but I know some have. My 1st and 2nd gen RX-7s only got about 18mpg when I was good to them and that was with around 100 LESS horsepower than the Renesis! The turbo II averages even less. The 2nd gens were rated at around 18/24mpg. The 18 was only attainable if I drove it like grandma. It is very noticable to gas mileage if I had done even a little spirited driving on a tank or if I hadn't. I only got the 24 mpg number a couple of times and that was on the freeway after I had done alot to the car and leaned it way way out. Look at the people on here who have more miles on their cars. They make more power and get better mileage than they did when they were purchased. Since the car is drive (throttle) by wire and very computer controlled it is feasible to think that it is in fact programmed with a break in type of period in mind. Mazda knows that many people are not going to break in their engines. A fantastic example of this is anyone who dynoed their cars before they had a couple thousand miles on them. You can't tell me that everyone waited until after 500 miles to rev the engine above 5000 rpm and until after 1000 miles to even approach redline for the first time. Anyone get the oil changed at 500 miles and then again at 1000? No one should have floored it for the first time until after 1500+ miles. No one does this and that is the recommended breaki n for all previous rotaries when an engine dyno isn't available. As an engineer with the available technology I would have definitely programmed in a break in period since most people don't know how to be patient. Pick almost any thread on here for proof. Running it rich and holding back some high rpm power for a while are great ways to do it. Everyone wants it in writing that the ecu does this but the evidence seems to point at this from other peoples results. Mazda spent tons of time and money on the 3rd gen engines by breaking them in at the factory on engine dynos. There are some neat pictures of these huge rooms of engines all running. Too bad they took shortcuts on other aspects of that car. All of the rotaries are still hand built and it takes tons of time to load them all onto engine stands for break in. I'd just put them in the cars and have a steadily reprogramming ecu. It all makes sense to me. Here's a great idea. Go to sevenstock 6 in 2 weeks and ask the main Mazda guys there whats going on. They'll be there, even the RX-8 program manager as well as one of the developers of Mazda's rotary engine. I still think there will be no problems with the ratings on the sticker once the mileage gets to a certain point. I still remember back in February when people said I was dumb (OK maybe I am!) for thinking that there was also a 4 port Renesis on the way in the auto and we do have it. Time will tell this one as well. The book was preliminary info. I love the car never the less and couldn't really care less either way. The rotary is back and with a little more time we'll be able to reprogram the ecu for better power and fuel economy.
Old 09-12-2003, 10:32 AM
  #31  
Registered User
 
astrlsrfr's Avatar
 
Join Date: Aug 2003
Location: San Diego
Posts: 40
Likes: 0
Received 0 Likes on 0 Posts
Tuning Parameters?

Originally posted by commentator
The difference in driving the car hard or easy goes without saying. I have not ready any posts the dispute that. The matter is not closed when it is obvious that there is way, way, way, way, too much discrepancy between the lowest and highest mpg reported by forum members. BTW if you read the government site i posted you will see that various driving conditions are taken into consideration in testing. Even those estimates are lowered to arrive at the mileage on the sticker. Conclusion: matter not closed something is terribly wrong here, to borrow a line from move.
Here, here. I have been getting 13mpg all the way to the 1500 mi mark I am currently on. This last tank I went with 89 octane and turning DSC/TSC off. I can already see the mpg will improve by about 2-3mpg. interesting, indeed - but not too surprising.

I have a theory about the wild mpg discrepancies. And, I know a way we can verify this theory. The theory is based on an analogous situation I face at work. I work in the cell phone industry as an engineer. When a phone is flashed (programmed), you typically have to replace the phones "tuning parameters". Every phone is different due to variances in the individual parts (chips & components) & the tuning parameters compensate for these variances. I thoerize that the car's motor & ECU system is similar w/ similar tuning parameters. When they were reflashing the ECUs at the ports, they may have botched up the tuning parameters for some 8s.

The way to validate this is based on a simple premiss: whatever is coming out of the factory now is getting the proper tuning parameters. If that is true, then the cars coming out of the factory after the port campaign should be getting better mpg.

Maybe we need a new poll?

Last edited by astrlsrfr; 09-12-2003 at 10:51 AM.
Old 09-12-2003, 10:46 AM
  #32  
Happy Owner
 
Kawi's Avatar
 
Join Date: Jun 2003
Location: Atlanta
Posts: 155
Likes: 0
Received 0 Likes on 0 Posts
I just checked yesterday morning and calculated 20 mpg. Well technically it was 19.9 but I'm being optimistic. That's with DSC still ON and mixed city/highway commuting. What I can figure is that I'm not sitting at lights as often as some folks so I don't idle as much. Dunno, I know it could always be better but so far I'm ok with the mpg I'm getting. It certainly has improved as the car gains more miles.
Old 09-12-2003, 10:55 AM
  #33  
Registered
 
Elara's Avatar
 
Join Date: Feb 2002
Posts: 4,447
Likes: 0
Received 0 Likes on 0 Posts
Originally posted by Superbone
How do you drive it, Elara?
If I'm cruising for any length of time over 30, it's in 5th. Over 40, it's in 6th. On the highway, I usually skip 5th, and sometimes 4th and go right from 3rd into 6th. But most of my driving is stop and go in the city, and I'm not babying it- redlining at least twice a week. Maybe I'm driving like the proverbial grandma. But I'm not doing it on purpose.

On the tank I'm on right now, I've got 230 miles and just over a quarter of a tank left to go. This is half city half highway.
Old 09-12-2003, 11:10 AM
  #34  
Senior Geek
 
RX8-TX's Avatar
 
Join Date: Aug 2003
Location: Richardson, TX
Posts: 1,005
Likes: 0
Received 0 Likes on 0 Posts
Gs are getting anything between 14 - 24 mpg (depending on transmission and driving habits)...if anyone would like the source, PM me....I won't post any address just in case we have pyromaniacs roaming around...
Old 09-12-2003, 03:31 PM
  #35  
Registered User
 
O.R.A.'s Avatar
 
Join Date: Aug 2003
Location: GA
Posts: 110
Likes: 0
Received 0 Likes on 0 Posts
When I had my WRX, I would get consistently 19-20mpg. I noticed that when I was out of town and my girlfriend drove the car, she got way better mileage than I did (like 25 mpg). I thought I was being conservative enough with my driving, but obviously not enough. I then tried being very, very conservative. Shifting around 3-4k, staying off boost most of the time and most important, being light on the gas pedal to stay on the range of the ECU where it is using the 02 sensors adn not just the fuel maps. Well, immediately my mileage jumped to 23-24 mpg. Very significant difference!

It also proved to me that I could either have fun with the car or have good mileage.

At least with the RX-8 you can run low octane!
Old 09-12-2003, 04:50 PM
  #36  
Administrator
 
zoom44's Avatar
 
Join Date: Jul 2002
Location: portland oregon
Posts: 21,958
Received 115 Likes on 88 Posts
Originally posted by Elara




On the tank I'm on right now, I've got 230 miles and just over a quarter of a tank left to go. This is half city half highway.
hey me too, well actually like 228 at a quarter. when i first got the car the light was coming on by 210 and was on the E by 220 in mixed driving.
Old 09-12-2003, 09:16 PM
  #37  
Registered
 
newport8's Avatar
 
Join Date: Sep 2003
Location: Newport Beach, CA
Posts: 72
Likes: 0
Received 0 Likes on 0 Posts
Re: Re: Re: Buyback for misquoted HP... what about the apparent missing MPG

Originally posted by Monster8


The sticker says the range for city is 15-21 mpg and 20-28 for highway. That sounds consistent with what most people are getting, though granted we all fall on the bottom side of that range. I don't think there's been any misrepresentation about the economy.
I have to respectfully disagree with that assessment. If the sticker says city driving will get you 18mpg with a range of 15-21 mpg, then I would expect the mean, mode and median mpg from city driving to be 18, and 15 and 21 to be at least one standard deviation to either side of 18. Falling within the range doesn't cut it. If they say 18 with a range of 15-21 and everybody gets 15, they've essentially mispresented themselves, statistically and otherwise. (I'm not saying they've necessarily done that intentionally, although I'll leave that open to the conspiracy theorists to debate.)

Of course, the posters to this forum are self-selective and probably not a normal sample (the ones who get below 18 come here to complain while the ones who get over 18 never bother to post anything), but still... show me the person who got 28mpg doing highway driving!

From the numerous posts I've read on the fuel economy issue, it sounds like the sticker should say city driving will get you 15.5mpg, with a range of 13-18mpg.
Old 09-13-2003, 05:36 PM
  #38  
Level 5 of The Pyramid
 
Butt Dyno's Avatar
 
Join Date: Aug 2002
Posts: 126
Likes: 0
Received 0 Likes on 0 Posts
just to chime in...

The EPA numbers have been right on, or slightly low, for every car I've owned...

My 1990 Bonneville, the numbers were pretty even, until some fuel sensor broke
My 2001 Neon, I actually got slightly higher highway mileage than the EPA said I would
My 2003 WRX, the EPA says 20/27 city/highway, and with about 60/40 highway/city I get about 24 mpg... and I drive the car pretty hard (spend a healthy amount of time above 5000 rpm)...

That's very interesting that the EPA does their testing on preproduction cars however... might explain a lot...

-bd
Old 09-13-2003, 05:52 PM
  #39  
Administrator
 
zoom44's Avatar
 
Join Date: Jul 2002
Location: portland oregon
Posts: 21,958
Received 115 Likes on 88 Posts
Re: Re: Re: Re: Buyback for misquoted HP... what about the apparent missing MPG

Originally posted by newport8


I have to respectfully disagree with that assessment. If the sticker says city driving will get you 18mpg with a range of 15-21 mpg, then I would expect the mean, mode and median mpg from city driving to be 18, and 15 and 21 to be at least one standard deviation to either side of 18. Falling within the range doesn't cut it. If they say 18 with a range of 15-21 and everybody gets 15, they've essentially mispresented themselves, statistically and otherwise.....
From the numerous posts I've read on the fuel economy issue, it sounds like the sticker should say city driving will get you 15.5mpg, with a range of 13-18mpg.
if by "they" you mean Mazda then no they haven't. it is not up to them what numbers or range of numbers are on the sticker as the mpg rating. that is entirely up to the EPA and the numbers the calculate during testing of the vehicles. also as one of the many people who have mentioned it , the cars are getting better mileage the more miles they have on them. most off the people who have 3k+ miles on their cars are getting 18+ in city driving now- my tank i finished last night was 18.4 mpg. my last highway tank was 23+.
Old 09-13-2003, 10:42 PM
  #40  
100% Italian
 
mikeb's Avatar
 
Join Date: Jul 2003
Location: orange,ca
Posts: 9,422
Likes: 0
Received 0 Likes on 0 Posts
I can live with 18mpg it was the 13mpg I got for the first 2k miles that was tough. It seems once I hit around 2k mpg has risen up to 18
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
WranglerFan
New Member Forum
9
08-21-2022 01:29 PM
OnebaddRx8
Series I Trouble Shooting
24
08-25-2019 11:34 PM
Jazzmeson
RX-8 Multimedia/Photo Gallery
11
03-02-2016 02:25 PM



You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Quick Reply: Buyback for misquoted HP... what about the apparent missing MPG



All times are GMT -5. The time now is 03:18 PM.