Ericok

(Commenting about my claim that the RX8 gas mileage is no worse than a lot of other sporty cars in its class) You can drive any car under the EPA estimates. RX-8 drivers push the car because its so easy to do and pay the price in gas mileage. If you visit the HUMMER forums, a big complaint is: mileage ("JD Power stated the #1 complaint of Hummer owners was bad gas mileage") Go figure. Here's a quote from the 350Z forum "Unfortunately, our heavy right foot and long stints in L.A. gridlock resulted in a pathetic 15.4 mpg over 9,300 miles. A quick check of forums shows that this is a common complaint among G35 owners." How about this from the Mustang (2004) forum "Cons: Gas mileage, and very small back seats". How about the EVO: "Cons: bad gas mileage, questionable tranny, cheap interior, rust on door panels". The only drivers that were happy about fuel consumption were Porsche Boxster owners but that engine puts out less HP than the RX-8.

Ike

<shrugs> I drive my car hard and go wot several times a day, have nearly 300whp, drive in alot of stop and go as well as city driving. I've gotten 20-24 mpg per tank my last 5 fill ups.

Sapphonica

Corvette Z06:

16-26 mpg
505 HP
470 ft lbs torque
1/4 mi: 12.4 seconds

Mazda RX8:

18-24 mpg
238 HP (as if!)
159 ft lbs torque (if that)
1/4 mi: high 14s if you're lucky


No, we don't need a car in the 12s, but if my car is going to get crummy gas mileage, it should at least be running low 13s.

The RX8 is so not going to be produced anymore after a couple more years of bad sales.

BunnyGirl

So what exactly are you trying to say in regards to my first post?

I mentioned likely not missing the MPG as much as people say because of the actual range.

You instead tell me about HP and MPG ratings for another car compared to the RX-8.

Sorry. No correlation. Nothing to do with meeting/not meeting fuel economy range.

Roaddemon

corvette Z06

$80000


rx8

$25000

Which one is most affordable? Which one has lower monthly payments? How many other cars in the same price range and class as the rx8 get the same mileage as the vette? These are questions you can answer.

BunnyGirl

If we want to go there, my friend's Ferrari gets 16 on average. We could buy eight RX-8s for what that car cost!!! Darn. I guess they're going to discontinue the RX-8 because Ferrari is doing so well with it's MPG and more power output!!!

RX8_GT

Comparing a Z06 and Rx-8 is just not on unless you compare price. I would like to see Z06 real world mpg.

If you want low 13s - get it third party turbo'ed ---- for a lot less than the difference in price of the Z06.

PS The Z06 is a great deal for a super-car class car IMHO.

RotoRocket

iTrader: (1)

Exactly!

Hell, they complain about gas mileage in the Hyundai Sonata forums, and I've even seen a complaint or two in the...gasp!...Mazda 3 forums!

sti_eric

Jeez people, the point of his post is that a 7.0L 505hp engine gets better gas mileage than the 1.3L in the RX-8. He is not comparing a corvette to an RX-8. Generally speaking, the bigger an engine, the more powerful it is and the more gas it uses. The rotary drinks gas like a big V8 but doesn't give you the same performance.

My 340whp STi gets better average gas mileage than we get out of the RX-8 on the highway.

SayNoToPistons

iTrader: (8)

where did you get those prices from?..... C6 z06 = high 60ks .... rx8 = 30ks...

BunnyGirl

I don't know the actual price they start at base but at the auto show they had one regular and one convertible. One cost $75K and one was around $81K. Not sure which was which and I don't know what kind of options they had either. I didn't pay that much attention since I don't particularly care for corvettes and never have.

BunnyGirl

My RX-8 is loaded to the hilt with the exception of essentially the cassette player, anything "cargo" related, door edgeguards, moonroof wind deflector (ugly).

Mine has an MSRP of low $36K. If I get rid of all the options base price is $26,995 including destination charges on an 06 manual. Base price for an 06 auto is now the same as the manual.

Roaddemon

The rx8 gets about the same average gas mileage as a large v6 or small v8. if the big vette engine is unique in it's mpg/hp good for it. Let's see it carry 4 people around the track, or wife and 2 kids on vacation. for a big powerful sports car it sure falls short of the simplist of tasks. What do you get for $80k? 2 less seats 500hp and a gas gussler if you drive it the way it was meant to be driven.

rotarygod

Time for another long RG rant.

I typically average 14-15 in my RX-7 but have gotten as low as 11mpg because I push that car alot. It's a play car anyways. It is quite easily capable of much higher and I've gotten over 20 city and 29 mpg highway before in it just driving normally. That's not as much fun though. My little Civic is rated at 28/32. I drive it very conservatively and average 34/37. That's way above the rated average and the only reason I keep that car. My parents have a little Civic as a daily driver and they do get the 28 average in the city but they have different driving habits than I do. I've found that different shift points and how I decelerate can affect mileage noticably.


If you want to compare engines with efficiency, do it properly. To say that "my 340whp gets better..."yada yada yada is inaccurate. It's not displacement that counts. It's efficiency at a certain power level. Let's just use freeway cruising as an example. Let say that the RX-8 needs to make 40 hp to hold it at 60 mph. I'm making that number up but it isn't that inaccurate. Hell, lets just say that a Corvette and a WRX also both need to make 40 hp to hold that speed. That'll keep things quite simple. None of the engines is making any more power than this if that speed is being maintained. Suddenly how large the engine is and how much power it can ultimately make are irrelevant. I assure you if each engine were making it's full rated power, the one making the most would use fuel the fastest. Lets get back on track though. It's known that the Renesis makes about 8 hp per each pound of air used in a 1 minute time frame. A good piston engine makes about 10 hp per lb of air used over a minute. We can already see that the rotary is less efficient based on this alone. That is a side effect of it's "long" combustion chamber in relation to a piston engine's. We can see that based on these numbers that it will take more air to hold the same power level as a piston engine. More air needs more fuel though.

The difference between a 10:1 afr is about 33% more fuel than a 15:1 afr. So now you know how much you can account for based on that. That's a sizable number. Most cars try to cruise right around 15:1 or so. However, time is also an important player in fuel usage. Specifically time at a certain rpm. Let's say you had a little engine that needed to run at a 10:1 afr to make that 40 hp to hold cruise speed. It's going to need 33% more fuel than the car that only needs a 15:1 afr. It's not as efficient. Cam timing, exhaust, intakes etc all effect efficency. The 10hp per lb air number is a generic baseline number. Each engine is different and obviously a car such as a Civic is much more efficient at cruising. We also need to consider that an a/f ratio and how much air and fuel is used is also a function of time or in simpler terms, rpm. If it took a higher load level at a lower rpm to make the same amount of power as a lower load level at a higher rpm, that doesn't mean that each needs the exact same amount of fuel. This is because of efficiency differences due to time and the amount of air/fuel being consumed in that time. Typically the lower the rpm you can hold a speed at, the better you'll do on fuel economy. As with everything there is a limit to this so don't get too technical on details.

We know the RX-8 has far more extreme gearing than any other car on the market in terms of final drive ratio. This means the Renesis is at a higher rpm over a greater amount of time more than most engines. Even if it was running at a leaner fuel mixture at these rpms's it is still a leaner a/f ratio over a greater amount of time and this alone may cancel out a richer a/f ratio over a shorter amount of time in another engine. We can see from this alone that the Renesis will be using more fuel than the average engine based on vehicle speed. Then we also factor in how much air the engine is actually using. In this regards it is not comparable to a 1.3 liter engine. It isn't even comparable to a 2.6 liter engine. Due to it's efficiency disadvantage based on how it uses air, it is closer to a 4 liter engine in terms of it's air consumption to fuel usage. Now some may say that a big 5.7 liter LS1 can still do way better than a 4 liter. The LS1 also cruises at a much lower rpm which takes alot less fuel over time than a 4 liter turning much faster. This accounts for much of the difference. Remember that fuel consumption is not directly related to power output. It is tied to efficiencey at a certain power level.

The LS1 is a very efficient engine. Can't take anything away from it. Everyone always compares the Renesis to it in terms of fuel economy but that's not very fair considering that you can't compare most other engines to it in that regards either if your only concern is size per mileage. In that regards it shames most which makes the rotary nothing special to compare it to. It wouldn't even be fair to a WRX to compare it's engine to an LS1. It'll beat a WRX in mileage on the highway. Let me guess, the WRX engine must suck? Nope. Compare what is really going on.

Get down to the science of it. It's obvious why the Renesis gets the mileage it does. There's nothing special about it, nothing surprising about it, and nothing new about it. It's a known fact that a rotary is a less efficent combustion engine than most piston engines. Comparing it to others is worthless though. We may as well compare all piston engines to others out there as well and ask why they all can't get proportional power levels as others. I don't see anyone bashing Ford based on the fact that their engines suck in terms of power and economy compared to Honda, the LS1, etc. They do if we are judging in terms of size.

The whole point of all of this is that these comparisons are all a waste of time. Usually by those who have limited knowledge on the subject with nothing better to do but with something to prove. Comparisons of the rotary engine to piston engines is a worthless things to talk about when determining if this car will keep selling well. All of these threads on total vehicle sales are a waste of time as well. These are all based on a person's opinion that the car should be selling more because other cars out there that they personally feel it is competition with have different sales numbers. The problem is that none of these people has any knowledge of what the car's projected sales are, none of them has any clue as to the vehicles profitability at those sales levels, and none of these people can be construed in any was as an expert or even a reliable consultant on the topic. It is always pure speculation and is almost always wrong.

The known fact is that the RX-8 sales are basically at pace with the Miata. Some may say this sucks. Others may say this is good. Keep in mind that the Miata is the best selling sports car of all time. Also keep in mind that Mazda does consider this car a sports car and that the RX-8 is faster than the Miata. Too all the people out there that don't consider the RX-8 fast enough to be a sports car, what is your excuse with the best selling sports car of all time? When you put it that way, is there really any relevance in comparing it to a WRX, 350Z, etc in terms of sales? I think not. Then again I think logically so that must be it.

RX8_GT

You missed my statement "I would like to see Z06 real world mpg." I simply don't believe 16 to 26 mpg for a Z06 driven in any performance way.

A rotary engine is never going to get the mpg of a piston - but the performance is there if turbo-charged - like the Corvette. And based on weight and physical size (and thus midship position) the rotary engine is unique and very high performance. Performance is not simply a straight line or a series of left turns.

Right now - I'm looking at a poster noting the six straight IMSA GTU championships of the 1st Gen RX-7 - against Porshe and BMW and others.

Mazda has produced a rotary sports car since 1978 until this day. it may have not marketed one in the USA from 1996 to 2003 - but the rest of the world had one.

Renesis_8

Nothing is perfect, most of the RX-8 owners know AND accept this fact, but you dont see them complain and cry about it, because the pros make up for the cons, and not only the pros on paper, it puts silly simles on their faces, they love this car, enough said.

They bought the RX-8 because of what the Mazda RX-8 have AND not have, they bought the <232hp 1.3L Rotary, that gets 16mpg simply because they love it.

Of course there are FAR more efficient engine than the renesis, but mileage alone just wont end the sales for RX-8, it'd be a combination of other things, including or excluding mileage.

There is no way around this problem, not until Mazda comes up with revisions to the Renesis, if mileage is bothering you that much, start appreciating what the RX-8 really is, take it the the track, find some twisties. Pretty sure that would leave some smiles on your face. If your still not satisfied, mayb this is not the car for you and its no biggie, we all+always learn by trial and error

RX8_GT

Rotarygod has spoken. (Very well I must say.)

Renesis_8

Roaddemon

[QUOTE=RX8_GT]You missed my statement "I would like to see Z06 real world mpg." I simply don't believe 16 to 26 mpg for a Z06 driven in any performance way.QUOTE]


The vette makes it's peak power at a very low rpm. At highway speeds in, top gear, It's basically running a little over idle If you really want some fun and use the 500 hp instead of poking along at the speed limit, you'er gonna burn some gas. I've heard low teens if you drive it like a real sportscar.

New Yorker

Maybe, just maybe, you're giving up gas mileage for the way the car feels and handles—not racing from stop light to stop light! Gee, do ya think!?!

I'm continually stunned—yes, stunned—at how many people here just don't "get" the RX-8!

Roaddemon

Maybe this will wake them up. The efficiency of a rotary is in it's small size(1.3L) to hp ratio. Because of that the rx8 is beutifully ballanced, solid, highsafety, reasonably quick, lightwieght fun to drive 4 passenger sportscar. There's nothing else like it. A 5L rotary, if it existed, would probably put out 1000-1500 hp. If you want efficiency the rotary is perfect for sportscar format.

rotarygod

Just for giggles someone compare a WRX, EVO, or SRT4 engine (or any other turbo engine) without the turbos to a Renesis or just for the hell of it, to an LS1. Let's see how fast the tables turn and who takes what side then! Would that then mean that the only thing that would make those cars worth buying or keeping is a simple few hundred dollar snail shaped hairdryer in the exhaust path? Things that make you go hmmm....?

RX8_GT

The small physical size of the rotary engine allows it to be placed well behind the front 'axle' --- the RX cars are basically midship engined cars. The people who have put V8s in RX-7s (A cardinal sin IMO !!!) change the very nature of car to a standard front engined car. I can only imagine the change in handling, etc.

Japan8

One of the JDM tuners (Fujita Engineering/ FEED) carries an aftermarket auto-dimming rearview mirror for the RX-8...

RX8_GT

Although not a 3rd gen - my 88 Turbo II kicks out very nicely. If the RX-8 is ever turbo'ed by Mazda - it will leave those other cars in the dust.

But for a four-seater - my RX-8 does very nicely and is a hoot to drive