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czr 07-21-2006 08:05 AM

Broke 20 mpg
 
Haven't posted in a while, but it only means no complaints :wink2: But after 31.5k miles, I have finally broke 20 mpg. I was actually at 20.4 mpg. Some things to note though: my commute has changed from 50/50 city/hwy driving to 40/60 city/hwy but was averaging 18 mpg and a one tank low of 14.6 mpg. As others have mentioned, at around this mileage the car feels broken in. It's hard to explain and I was a doubter at first, but it feels smoother and easier to wring out the power now! The gas thing is a bonus.

Hightshoe 07-21-2006 08:58 AM

Havent you ever had a tank, when you were on vacation or something, where you drove all hwy miles? You must surely be able to get more than 20.4mpg on a tank when its all hwy. If I have a tank thats all hwy and cruise between 70 and 80 mph, which can be upwards of 4k on the tach when you get to 80, I can still get the full 24mpg.

spork 07-21-2006 10:34 AM

congrats... i've been waiting for this myself. It's nice to hear that this may still happen for me (i'm only at like 20k miles, but i need to figure out if i'm keeping the car or not).

my closest has been 19.5mpg doing like 85% freeway. i've gotten over 20 once, but i don't count it since i got it when i refilled my tank early (like before i even got to halfway empty).

Aseras 07-21-2006 10:39 AM

It doesn't matter how I drive my rx8, I almost always get 21.XX mpg. 30/70 city hwy mix

also there was a definite change around 20-25K miles in the engine. much better feeling and smoother than when i bought it.

the only exceptions to my mileage is if i get crummy gas ( it happens i can tell within 20 miles the car starts to feel like crap ) or if i'm on a long highway trip and keep it at around 75 and then I've gotten over 26 mpg several times. my first 320 mile gas light tank had me thinking the gas gauge was broke.

chiefy 07-21-2006 11:03 AM

My car - 190 MT (5) has done 3000 miles. All motorway driving at 70/80 I get 32 MPG and 50/50 town/highway I get 29/30 and all town and lots of traffic I get 25 MPG. Those are UK Gallons which are 1.2 X US Gallons.

Stavesacre21 07-22-2006 08:06 AM


Originally Posted by Aseras
there was a definite change around 20-25K miles in the engine. much better feeling and smoother than when i bought it.

so it must not have just been me. I pulled my 8 out of the lot with (ironically) only 8 miles on it. Maybe it was because the engine hadn't really been ran, but I thought that on the intial test drive, the engine wasn't very smooth at all! I felt like it was a rough sewing machine! It quieted up significantly in the 3K miles i've had it...but I thought that was funny to hear from someone else. Rather bumpy to start...

Anyway, about the MPG....yea that's a bummer it has taken that long! When i travel almost all my miles HW, I very rarely get below 22MPG. I always thought that it was some people roughin there engines more then others, but that sounds like there really is another factor involved. I'm really hoping you keep climbing that shallow 20MPG incline and come close to the 24 it stated sometime! Good luck! :icon_tup:

kartweb 07-22-2006 08:41 AM

Both my RX-8 and CX-7 AWD get about the same mileage - 21.5-22.5.

Most of my driving is a 42 mile ride on the freeway at a steady 75 MPH.

In contrast, 3 other vehicles for the same trip;

1997 Thunderbird 4.6 liter - 22.5 MPG
1976 Porsche 914 2.0 - 36 MPG
2005 Nissan Altima 2.5 - 32 MPG

BunnyGirl 07-22-2006 09:44 AM

I calculated my mileage out after filling up yesterday and I got my best mileage ever. I got 25.61 MPG!!!! I had 292 miles on the trip, was just hitting the quarter left mark. The pump clicked off at 11.4 gallons. This would be about 30/70 or 40/60 city/highway. My 70 mile commute to and from work each day is mostly highway, but a good chunk of that is spent in stop and go, stop and go. It's about 34.5 miles one way to work and I spend about 15 of them in slow moving stop and go and then downtown driving with stopping basically every block. My commute usually yields low to mid 23s.

Of course, my current tank is getting terrible mileage since it took two hours to get to work last night for my mandatory overtime. It usually takes 45-50 minutes if there are no traffic issues and 50-60 minutes if I catch traffic starting to back up at the early part of rush hour (usually leave at 1:30, get there by 2:30, to start work at 3:00; if I leave even five minutes later it adds 10-15 minutes on to my commute) I left my therapy appointment at 3:30, spent about 5 minutes getting gas, and then proceeded to drive to get to I-205. After about a mile into my driving on I-205 traffic just came to a dead stop and then would occasionally move at about 8 MPH. At one point will sitting and doing nothing I looked at my temperature and it said it was 110 outside. Yuck! I finally pulled into the parking garage at 5:28.

MP3Guy 07-22-2006 09:52 AM


Originally Posted by Aseras
It doesn't matter how I drive my rx8, I almost always get 21.XX mpg. 30/70 city hwy mix

the only exceptions to my mileage is if i get crummy gas ( it happens i can tell within 20 miles the car starts to feel like crap ) or if i'm on a long highway trip and keep it at around 75 and then I've gotten over 26 mpg several times. my first 320 mile gas light tank had me thinking the gas gauge was broke.


This is not bad real-world mileage- my wife's 4 cyl Passat does about the same, and to get higher highway mileage takes real coaxing. And it doesn't sprint like an RX-8 does.

Did all of you guys drive Civics before this?????
:D:

Kewl 07-22-2006 11:02 AM

Here's one for you. I recently got a ScanGauge II and my mileage went from about 19 to close to 21 mpg...mostly city driving. The increase was caused by the ScanGauge? No. Well yes and no. Using the ScanGauge I have found that when forced to drive at a set speed, like 30 mph, the scangauge lets me look at the best gear/rpm for the speed I was traveling. The goal, for me anyway, was to maintain an rpm that felt best for the engine...aound 2.5 for 35 mph. Even more interestingly I found that even in the city using the cruise control where I could made for much better mileage.

Scangauge II... I saw it in the current Motor Trend issue while flying to Colorado Springs and got one when I returned home. www.scangauge.com if you are interested in seeing what it is. A very handy tool...for all my vehicles, not just the 8.

JeRKy 8 Owner 07-22-2006 11:11 AM

I doubt this has anything to do with your car being at 31k miles. The amount of time you spend driving on the highway is a HUGE factor since the engine is so touchy about consistency. Even as little as 10% more highway driving will make a difference in your fuel efficiency.

I used to average 16 - 17 mpg doing 80/20 city/highway ...and before that, I was getting 15 - 16 back when it was 90 - 100% city driving.

Now that I drive predominantly on the highway during the week, I'm doing 30/70 city/highway and I'm averaging 20 - 21 mpg. Also, I don't go WOT nearly as much as I used to, which also helps mileage (obviously).

czr 07-22-2006 03:51 PM

I've gone on trips before 90% hwy and never broke 20. Albeit, my cruising speed is at 75-80mph with rpms @ 4k and I don't baby her going wot at least once a day and through most sunpass tolls.

Old Rotor 07-22-2006 05:55 PM

I'm geting near 30k on mine and my mileage has improved 4mpg from when it was new! Most of my earlier rotarys would improve only 2mpg, and now twice the HP for the same c. i. They have come far on this exotic engine doing it all on there own! Look at this old one its a good read and the graphics are unbelievable unless you lived then, now you can see how Mod...... Mazda was....

http://keith.miata.net/110S/index.html

Easy_E1 07-22-2006 08:29 PM

I can get anywhere from 17.4 to 23.2 depending on how I drive.
Seems to get the best at about 3500 to 4000 RPM on the freeway. Thats 75 to 85 mph.
Have gotten 140 miles out of a 1/2 tank one time.
That was when I switched to Shell 91 octane.
Oh by the way it is an AT trans.

Stavesacre21 07-22-2006 08:43 PM


Originally Posted by Old Rotor
Look at this old one its a good read and the graphics are unbelievable unless you lived then, now you can see how Mod...... Mazda was....

http://keith.miata.net/110S/index.html

wow...that was one...psychedelic brochure. Granted that at the time it came out, it was likely to be pretty awesome. Regaurdless, very interesting find. :smoker:

NgoRX8 07-23-2006 12:00 AM

i still get 19 all highway. oh well, whatever.

sojourner 07-23-2006 12:11 AM

I am currently getting about 16-17 mpg, with all city driving. But I took a 250=/- one way trip about a month ago, and ran in the triple digits for about a quarter of the time, and at the next fillup, surprise!!! 23.8 mpg. Go figure. Oh yeah, I am at just under 8k miles.

Stavesacre21 07-23-2006 08:20 AM

I'm glad the low fuel light gives you at least 2 gallons though. I was in unchartered highways our in PA a month back and found that I ran that car down to less then 1/2 a gallon in search of a station!

I've been in another car that gave you 1/2 a gallon with the low fuel light :banghead: and also a 1990 pontiac bonneville that...get this...had a light that came on when you RAN OUT OF GAS. And yes, that's exactly when it came on...when you ran out. Yea...that one was pretty useful. I'd like to know how such a STUPID dash light ever passed approval on the drawing board...

JeRKy 8 Owner 07-23-2006 01:46 PM

I think another factor behind my gas mileage improvement on the highway is that I usually set it to cruise at 60mph, or 3000 RPM in 6th gear. Sometimes it's annoying and even frustrating to drive that slow when you have everyone else going 10 - 15 mph faster than you, but it seems to make a difference in gas mileage. For those of you doing 70 - 80 all the time try dropping to 60 for a day and see what happens. Oh and try not to get rear ended

williamngRX8 07-23-2006 02:20 PM


Originally Posted by BunnyGirl
I calculated my mileage out after filling up yesterday and I got my best mileage ever. I got 25.61 MPG!!!! I had 292 miles on the trip, was just hitting the quarter left mark. The pump clicked off at 11.4 gallons. This would be about 30/70 or 40/60 city/highway. My 70 mile commute to and from work each day is mostly highway, but a good chunk of that is spent in stop and go, stop and go. It's about 34.5 miles one way to work and I spend about 15 of them in slow moving stop and go and then downtown driving with stopping basically every block. My commute usually yields low to mid 23s.


i hate you :smoker:

DOMINION 07-23-2006 07:03 PM

You know I dont like useing Chevron. I get bad mpg with them. But Shell is great.

Old Rotor 07-23-2006 11:29 PM

On my first tank I got 23.5mpg at 65mph. Now with almost 30k I get 27.5 mpg at 65mph. This engine is looser and revs freer. It's hard to keep it at 65 so I only do it once in awhile.

BunnyGirl 07-23-2006 11:55 PM


Originally Posted by DOMINION
You know I dont like useing Chevron. I get bad mpg with them. But Shell is great.

That's funny because my car loves Chevron but when I have used Shell the mileage dropped and the car didn't run as smoothly. I think the dealer put Mobil in it for the first tank since that station is only about a mile away from the dealership. That was my worst mileage ever but that was when I was retarded and couldn't hardly get my car going. LOL

I know this tank of gas will probably only get me about high 21s to low 22s since I spent two hours on Friday sitting on the parking lot otherwise known as I-205. It took me two hours to get to work in what is normally a 45-55 minute commute. This is also considering the fact that I started out 15 minutes closer to work and also subtracting the few minutes I spent at the gas station. I technically started counting the time it took me to get to work from the time I left the gas station, so I was really about 20 minutes from my house and closer to work. Traffic sat there stopped most of the time and when we did move my speed registered 8 MPH the virtually the whole time. I think I hit a maximum speed of 15 until I got off I-205 and onto I-84. :eek: Of course it was just wonderful that the temperature outside registered 110 degrees inside a car with black leather interior. :rolleyes:

As it sits right now when I got to work I am one line above the half mark with 152 miles on it. Another thing that will eat up my gas is the fact that I drop it off at the body shop tomorrow. They let it run for a really long time so they don't flood it. They are detailing my car for me for free. :) I guess it works out fine that it was far too hot for me to wash my car this weekend. Poor Bella is all dusty, then got a brief 10-minute rain, and now has dirty splash marks all over the sides from the road.

DrDiaboloco 07-24-2006 01:19 AM


Originally Posted by Old Rotor
It's hard to keep it at 65 so I only do it once in awhile.

Do you REALLY have that little self-control? :)

Javafuel 07-24-2006 02:24 AM

the age of topic. After 36k fun miles, my 8 mpg is still around 20 from 25/75 city/freeway, plus LA rushhour traffic.

Two things I notice about my 8,
1. The mpg difference between normal driving (change gears around 35k rpm, keep it under 40k rpm @ 6th gear on freeway) and sports driving (driving it in the ways it was designed for) is only about 30 miles/tank.

2. The fuel indicator is kinda wacked. Sometimes it would ran 170 miles on the first half of the tank, with the same driving style the second half would only ran about 110 miles. But it always ended up about 280 miles/tank. go figure.

So I asked myself, why did I buy the 8? the answer addressed mpg issue once for all (personally speaking).


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