According to:
http://www.mazdausa.com/MusaWeb/disp...ehicleCode=RX8

The Auto and Manual have different gear ratios:
- Auto, 4th gear, 0.694
- Manual, 6th gear, 0.843

I think my AT is below 3750 at most expressway speeds.
<edit>
I checked twice recently, 80 MPH is about 3350 RPM
(1.5 needle widths over 3250 RPM)
<edit>

Is the 3750 RPM cut-on the same for ATs?

 

Wow, I admire your self restraint!

Hmmm, don't know if I can STAND driving like a granny for another week! Perhaps week after next I'll try the 87 octane, and drive like a granny, to see if I can get 20 MPG in the city. Hmmm.



As for the gear ratios, I think a tall 6th gear is the best solution for highway economy. Just tall enough that 80 MPH would be turning the engine at 3500 RPM. That'd be ok in my book - I don't mind downshifting to pass!

Mazda, are you listening? :D

 

I just did my first fill up today.

233.6 miles / 12.214 gallons = 19.126 MPG

This is still in break in with moderate driving under 6000 RPM. I've been trying to shift around 3500-4000 RPM on average. I'm assuming the first tank from the dealer was 91 octane. I'm using 93 octane from my local Exxon.

 

That's pretty good - I did an extended trip last night from San Diego to Burbank and back again - lots of freeway cruising (but not at 60mph, more like 82-85) and got 20.7mpg which is about the best I see. With my normal driving style I see around 17-18mpg. If I'm having fun, I've seen 15mpg. So yes driving style, shift points, how fast you accellerate from speed A to speed B etc. seem to have dramatic effects on mpg. Although I still think there's a small number of people who actually have some kind of car problem where they get horrible mileage regardless of their driving habit... I wonder if any of them have checked their intake for oil? I could imagine an oily MAF could really hose things up.

 

I think if you are driving for nothing but gas mileage that's great, but also realize that you probably foul you plugs up quicker than those who use the whole power band.

 

Driving at 3,750 rpm in a 6-speed, which gets 19.4 mph/1,000 rpm, = 72.75 mpg. 88.125 in my AT, which gets 23.5/1,000.

BTW, I'm almost always way under 3,750 in the city, and still get around 15 mpg in my early-VIN car. The dealer says the ECU is properly set, and offers no other solution.

 

There is another thread on 87 octane that is more in depth but I gave the 87 a try and it resulted in a 2 mpg increase with my same moderate driving style. Now how this will hold up is another story but the car seems to run and idle a bit smoother. I guess 87 octane is fine for a stock car and normal to moderate driving in mind, but for aggressive driving (redline) and performance mods, I would definitely stick with 91 octane.

 

I have the auto trans(medical reasons). At 3000 rpms my speed is 73mph. It is hard to keep the revs down but I have never got lower then 20mpg on the 8. This is my 7th rotary since '71 and its more fun then any other.

 

just blasted out my best tank yet. 22.8 with the ac running.

fla in the winter sucks. most of the tank was run with shifting from 1st to 3rd to 5th 6th. all before 3.5krpms.

then running the interstate at below 3750rpm. i think the next tires are going to be taller. so i can run 80mph at less than 3750rpm.

tank before 18.8 with tcs and dsc tests and two top speed runs. 138mph. but the area i test in is short.

love this car.

beers

 

UGH that explains the RX8 I was stuck behind in traffic last week... The guy was going 50 on the highway. I pulled up next to him trying to encourage him to either drive the speed limit or trade his Silver 8 in for a Mazda 3.

Then I downshifted into 4th and screamed ahead of him... he did not follow. Oh well.

 

OK, I don't know much about tuning and piggy back units, but could the point at which the second set of fuel injectors kick in be changed with either of these two options? In my naivety I believe that the kick in point could be “moved down” to increase performance or “moved up” or removed all together to increase gas mileage.

Can anyone tell me if this would be possible? It would see an in cockpit setting for this could be very useful …

 

I think you have a good idea. Why not have a switch for max hp,gas mileage and lower hp(when you loan it to someone that might not have the need or experiance)..... to handel it.

 

What is the right acceleration rate for stop and go city driving?

I have a 6 mile drive to work with 4 stop signs and 4 stop lights. I start out gentle because the car is cold, but about 1/3 of the way into the drive the temperature needle is moving pretty good.

I would guess that hitting the 2nd injector at 3750 RPM for "city stop and go" won't get me the best MPG, and may not be the best for car, and best for the car is also an issue.

In granny mode I could keep it around 2000 RPM or less, but that almost feels like the car is out of its power range, and I am wondering if the mid-2000s or higher might actually improve the MPG.

To get the best MPG, what is the best RPM range for frequent city acceleration from a full stop?

 

Mazda outlined in the book when to shift, its something like 14 MPH in first gear, I forget the rest. I found that shifting at 3000 RPM yields enough power for day to day driving and will get you the best gas mileage.

you get 90 pct of your torque by 3000, so its enough for day to day.

 

I've been saying this for I don't know how frikkin long that if you keep the rev's down you can get 19mpg like I do.

...besides, I'd rather drive slowly - its easier to pick up the chicks when your not flying by them :D .

 

zerobanger --

Thanks, I will try accelerating from a stop such that it shifts before 3000.

 

Yeah, but it's SO hard to do! :D

 

ugh- I've been shifting low and holding my rpms to 2500 for the past two days- at 120 miles I was still 2 notches above halfway, in ALL city driving, BUT....I couldn't take it anymore. On my way to the gym this evening I gave up on the experiment and drove like a banshee.

 

I also found out that keeping the rev below 3500 rpm has improved my consumption drastically. I had 150 miles on the clock at the halfway mark, my best ever. Like Elara, after a few days my right foot started itching and I went cuckoo.

 

Hope I can make it longer...

I finally broke the 20 mpg barrier with my last tank. Of course, it was 98% highway driving with the cruise control set to 72-75 varrying depending upon what traffic was like. I got a 20.45 mpg on 87 octane.

Since 1/10/04 I have had this car and have not done a large percentage of highway driving alone on a tank of gas. Even this was not a good measurement because at least 45 miles was done on a two lane road where I averaged around 60 with slower periods going through small communities. Most times in town here I get around 13 - 14 mpg.

This tank full I am keeping it under 3500 rpm and will see what driving like a granma feels like. As others have said trying this method, it was very hard to do today and almost to the point of being painful.

I did find out that in 6th gear at 3500 rpms it is going 70 mph. So, this will be ineresting to see if it does what others have said.

 

And furthermore I do NOT plan on driving like this very often after this experiment, unless I start getting tickets, God forbid, but I did buy the Velocity Red...

 

Sorry for quoting old entries in an old thread; but I was wondering if the anyone figured out how to get a 6th gear with a ratio closer to the top ratio used by the Auto transmission. I am given to understand that the top gear in the 2007+ auto is even a bit taller than the one from the 2004-2006 models (though i could be misinformed).

Does anyone know if the other markets where the RX-8 is sold have the same gearing as us? If not, do they have a taller or shorter 6th gear? I find the jump from 1-2, 2-3, 3-4, and 4-5 just fine for me; but I find the jump from 5-6 much too close for my liking, so I'd ideally like 6th gear to be a bit taller.

Coming back to the topic, I find that even if I drive with revs limited to 3000 in the city, I find that it only is viable in Spring and Autumn, as the AC, especially in dense and jammed traffic can and in at least one case did eat more fuel in a half mile than a 40+ highway trip (results I observed just two months ago, so this was not hypothetical but actual observation). I am planning to get a Scangauge II so I can better fine-tune my shift points as well.

 

I have been shifting much quicker keeping my RPM's down in South Florida traffic. I have also been taking it out of gear when coasting. I have not kept track of my mileage but notice my gauge is not dropping as qucikly as before. That is in traffic. I still exercise my baby on certain roads I driive on daily and do redline at least once a day. I guess it is a mediation of sorts and still enjoy what I bought this car for.

 

2004 thread. Kinda cool to look back at gas prices

 

On my last road trip I got 27mpg. I wasn't using cruise control, doing a fair bit of lane changing, and averaged 80mph. I left it in 6th most of the way.

My last stint of city-only driving saw me at 20mpg.

Driving it the way it's supposed to be driven usually nets me closer to 16-17mpg.

'07, build date 10/06, 6700 miles as of the day of this post.