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Mazda RX-8 Gas Mileage Reports

135

Comments

  • pathstar1pathstar1 Posts: 1,015
    If we talk literally then the renesis is only a few years old. The renesis is based on the earlier rotaries, however. In fact it is very close to the same except for the side exhaust ports (some performance builders are using renesis parts when rebuilding older motors as some of them are improved/lighter - and they fit, just so you see how close the engines are). The earliest rotary car from Mazda that we saw in North America was in 1968, as I recall (the R100). So that would make the engine design at least 38 years old. The basic design hasn't changed much, but the materials have changed a lot - for the better. ;)

    Early on Mazda tried using side exhaust ports, but in those days the apex seals were very experimental (read unreliable) and needed a lot of oil. This very quickly plugged the side exhaust ports so Mazda had to put the ports on the rotor housing for production vehicles. So the renesis is really not new, just vastly improved over the previous designs.

    What was improved?
    1. Moving the exhaust ports to the side housings allows much better control of the port opening timing, resulting in potentially better mileage and better power.
    2. Many moving parts were lightened, raising the redline from 7500 RPM to 9000 RPM (the side exhaust ports also helped with this - when the apex seals traversed the old ports on the rotor housing they "bounced" a lot at high RPM and this eventually resulted in seal breakage). Of course when I say "many parts" I'm talking of only many compared to how many there are - there are very few moving parts in a rotary engine!
    3. The PCM (engine computer) is greatly improved, allowing much better control of the engine and providing much better protection for it.

    So you are both right in some way!
  • late8late8 Posts: 7
    '06 RX-8 Sport/3500 miles. Average 40% city/60% highway, I'm getting 20 mpg. Love the ride!!
  • murfbearmurfbear Posts: 17
    I have a 2006 RX8 Shinka 6-speed. I only have 450 miles on the vehicle. At my last check I'm only getting on average 17.5 MPG, I haven't been on any extended hi-way trips, but I feel my miliage is a little low. Break in is 600 Miles, will the miliage get any better with break in? I feel I drive fairly conservative.
  • trispectrispec Posts: 305
    Heck, I'd love that number. I'm getting 14MPG in Boston traffic in my 2005 RX-8 AT. But I get 23MPG at 85MPH and 25MPG at 60MPH pure highway.
  • geckozoidgeckozoid Posts: 3
    My '02 Mustang GT (manual trans, zero - 60 in about 6.2 seconds) with 82,000 miles on the clock gets 28.5 mpg highway, and 20 mpg in town (lots of first and second gear). Seems to me that's better mileage than most people are reporting in this forum for their RX8's. And the Mustang has never needed a drop of oil between changes.
  • ClairesClaires Chicago areaPosts: 974
    Hi, geckozoid,

    You might want to post those numbers in our Ford Mustang MPG: Real World Numbers topic. Or, if you'd like compare and contrast the Mustang vs. the RX8, you're welcome to start a new topic. :-)

    MODERATOR
    Need help getting around? claires@edmunds.com - or send a private message by clicking on my name.

  • murfbearmurfbear Posts: 17
    You think you might want to try the mustang forums? This is the Mazda RX-8 area.
  • trispectrispec Posts: 305
    MPG is a stereo typical consumer benchmark. It is meaningless without context. RX-8's are rev happy driving machines. 'Stangs are straight shot torque heavy brute machines.

    Now lets take both cars to a non-NASCAR race track. Which car gets better millage going around the track. In the hands of a pro driver the 'Stang's MPG drops like a rock down to 5 MPG where the RX-8 gets 7 MPG. The way to drive a 'Stang around the track at it's fastest is much less efficient than the way to drive an RX-8 around the track. Plus the pro drivers would probably choose the RX-8 as they would be able to win more often with it's intelligent balanced drivability over the 'Stangs raw brutishness.
  • div2div2 Posts: 2,580
    I've been lurking in this forum because I'm considering picking up a used RX8. I've enjoyed reading your comments on the car. I usually hang out on a few of the BMW boards and over there we frequently get those "My [insert make here] is faster/cheaper/better then a BMW" postings. I'm glad to see we're not alone...
    To paraphrase one of my fellow Bimwads, I doubt many RX8 owners lie awake at night wondering if they should have bought a Mustang :P
  • trispectrispec Posts: 305
    I do enjoy 'Stang roasting when giving an opportunity. The MPG thread was just such.

    Agreed 'Stang envy is not a problem here. An RX-8 sighted on the road still strikes me as "Wow that looks good, and I'm driving one". Where as the new 'Stangs looks like that '70ties show sans the chrome. ;)
  • I recently returned from a month-long cross-country trip, about 6800 miles, in my 2005 RX-8 (6-speed).
    While I do like the Mustang's looks, I chose the RX-8 because of my prior experiences with the RX-7 (owned a 79, 83 & 86). In 35 years of driving, I have never gotten as much reaction and praise as I have with my little red rocket. I didn't buy it for looks, I bought it because it's fun to drive & makes me feel like a kid again. I now have almost 9000 miles on the car & it's been virtually trouble-free. Also, gas mileage was better than I expected -averaged 23-24 mpg on the highway, with a few tanks at 25 mpg.

    Mazda needs to advertise the 8 more!!
  • murfbearmurfbear Posts: 17
    I have to agree with Flipper897 Mazda needs to advertise the RX-8 much more often, I think it sells well enough with the current exposer but with just a little more push sales would explode, besides I'm getting tired of the same old Ford Chevy Dodge and Honda pitches. Lets see some RX-8 VS, ?? any model you make the call.
  • dwynnedwynne Posts: 4,018
    I get around 13-15mpg in town in my 05 RX-8 GT w/6 speed. My commute is about 12 miles each way about 1/2 stop and go and 1/2 freeway.

    I drove a 380 mile round trip yesterday it was almost 100% interstate with only a couple of stops. Speeds were 60mph up to 73mph, depending on which state and if we were in town or not. For the first tank, I got 21.5mpg.

    For reference, in my 2005 S2000 I get 23-25mph around town and 27-29mpg on a trip - all with the top down.

    They only good news is that gas has dropped here to under $2.50 per gallon for premium.

    In the long term RX-8 test update in one of the car magazines, the commented on how expensive the 8 was to run in terms of always adding oil and how thirsty it was at the pump. "This is why no one else makes a rotary engine". The car is nice and fun to drive and the rotary is smooth, but I have owned 345 mph and 394hp (stock) cars that could deliver the same or better mileage and own a car with similar power and redline that gets a TON better.

    Dennis
  • trispectrispec Posts: 305
    This seems a bit trollish, but I'm gruff'n having just blown down I95 from Portland to Boston in my 2005 RX-8 AT. This time of year, between labor day and the beginning of leaf peeping season, the I95 Portland to Boston run is stunningly fast.

    I got 23MPG averaging 85MPH.

    I also believe, the RX-8 far surpasses all the competition. During the year I've own my RX-8 AT, I've driven 16K miles, where 6000 of those miles were highway. Long stretches of highway cruising needs a car to be roomy and comfortable, fun to drive, and capable of carrying the average U.S. family and all their weekend stuff.
  • w9cww9cw Posts: 888
    I'm not sure when the R100 was imported, but I had a friend who had a NSU Ro80 and it's fuel mileage was quite poor. Of course, Dr. Wankel's rotary design is not known for fuel economy.

    I bought a new Mazda RX2 in 1972, and loved the car, except for the gas mileage. And, as "pathstar1" says, apex seals were a problem. I loved driving that car, and gas was cheap at the time.
  • dwynnedwynne Posts: 4,018
    You have about 2x the miles on your 8 than I do - but I have other cars and motorcycles to share the transportation load :)

    I just report what I get. Driving around town there are lots of variables - do you redline, do you putt putt, etc. But on a trip where you just set the cruise and drive (straight line boredom) there is not much I could do to make it better or worse. Maybe after more miles are on my car the numbers will pick up.

    I agree that the car is unique - but that is not 100% a good thing. As I said I got better MPGs in cars with a LOT more horsepower than the 8 - the rotary is just horribly inefficient.

    Dennis
  • trispectrispec Posts: 305
    My normal Boston commute is for the most part, along a 30 mile round trip of tree lined neighborhoods where speed limits of 35-40MPH predominate and where Boston cops live to catch speeders. So horse power means nothing as it would be completely wasted in my driving environment.

    What does matter enormously, is having a car that pulls .93Gs through Boston's famous traffic rotary systems and winding cow path road layouts with three passengers. Makes the daily commute quite invigorating.

    Sure I pay 20% to 30% more for gas, but my passengers would much rather ride in my RX-8 than any other car. They pay me for the priveledge in fact. The car is known as "Therapy car" in my commute cycle.
  • dwynnedwynne Posts: 4,018
    You are also driving the "de-tuned" auto tranny car . If you had the full 238hp of the 6 speed cars then maybe you would get numbers similar to what my 6 speed returns ;)

    You must be short and have short passengers too. I love my 8 (except for the mileage, recalls, and lack of resale value) but my 6'+ sons really have trouble fitting in the car with me - and pretty much no one can ride behind me (and I am not that tall). But driving solo it is fine - and close to the thrill of the S2000. With a VooDoo knob the 6 speed in the 8 actually has shorter throws than the S gearbox - which has a very tight pattern.

    Lots of cars can do close to a g in a corner, and have more power to pull out of it. My M5 could, for sure :) I prefer a lighter, more tossible car however - which is why have both the s and the 8. Looking at the prices on the mazdaspeed6 I have been tempted to sell the 8 and get one (Mazda has a knack for making great cars that they can't sell) - but it is a good bit heavier than the 8 so ultimately would be less fun for me to drive. Ditto the new G35 - more passenger room, more ponies, better gas mileage, fewer (likely) recalls - but may not be as much fun.

    Enough of that, since this is the MPG forum - I will just state again 14-15mpg around town and 21.45 on a 95% interstate commute is lousy gas mileage for a small car. Good thing premium here is down under $2.50 a gallon :surprise:

    Dennis
  • trispectrispec Posts: 305
    Had to give up on clutches. Besides all cars are going to the paddle shifts. Even NASCAR is thinking about going to auto shifting with paddle. Auto-shifters do shift about ten times faster than pro drivers can.

    Mazda was aiming at a price point, that's why the auto tranny can't go over 7500. An auto-tranny that can handle 9000 RPM starts to get expensive. The Caparo T1, needs a $13,000 paddled shifted 6 speed auto tranny to handle it's 12000 RPM racing V8. Sticks are definitely going the way of the dodo bird, I think.

    Beside Boston traffic jams pretty much destroyed my shifting knee and angle after 15 years of sticking it.
  • trispectrispec Posts: 305
    Simple really. Changed my commute route to maximize my ability to coast in full automatic mode. Gone from 14MPH to near 18MPH in the city.

    I had long taken Pathstar's advise about keeping RPMs above the 3000 level via manual mode paddle shifting, because of wanting to guard against carbon build-up.

    But then I realized that coasting 50% or more of my commute would keep carbon down even better. There just so happens to be a certain odd combination of routes where, although traffic is heavy, coasting is also almost continuous through out.

    So rather than trying to have fun on less crowded hills and curves where coasting is just not practical, I'm commuting the slow and steady route with a massive traffic flow.
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