spieder

I notice quite a few people here get bad gas mileage. I also notice that quite a few of you use excessive oil. I was wondering if this was a link between the two.

Here's my thinking and background:
I have owned nothing but rotary cars since I was out of high school. I have always got good mileage and never had to add oil in between oil changes. Currently, my 8 is using oil on par with my RX-7's. I have 2300 miles since my oil change and am 2/3 up on the dipstick (no oil needed). I tend to think that since I notice that the people who have to check oil every other fill up are also the peopel with bad gas mileage. I suspect it has to do with the 6 speed manual. I read on Ca's website for cars that the average (for RX-8) auto driver reports 20 mpg and the 6 speed manual reports 16mpg.

If you read the instruction manual, the shifting for normal driving is quite intensive. It's almost every 5 to 7 miles per hour. I actually try to follow this but it is very hard. It is possible that people are driving the 8's as a 5 speed with an overdrive, instead of a 6 speed.

As for the excessive oil, I would consider that an indication of excessive throttle and hard driving. Any one else have any ideas along this line?

Philip_SA

One thing I notice for myself was that at times I am still in 5th or even 4th gear just because it actually are then very "nippy" fast reacting,this will make a differance.but on long distance I actually push it in third and skip to 5th then sixth sometimes straight to 6th.
The harder you drive it the more oil it will use and also heavier on fuel.The best that I realy tried to get a good run was on long distance I got 9,2kilometers to a liter of fuel, not bad at all.but no full throttle.I think my oil usage are about the same as yours.

swoope

iTrader: (5)

you dont mention how many miles you have on your car, but mine was the same way. i could go almost between 5k mile oil changes without adding oil.

got a cel at ~ 22k miles. it was the mop. they were just investigating at the time.

at 32k miles, it was replaced. it does use more oil now which i think is going to be better in the long run.

mpg before ~21mpg after the same.

i think most of the bad gas milage is caused by excessive idling and dirty plugs due to the first.

beers

msrecant

I have had several rotary cars dating back to 1972 and was quite surprised over the fuss about RX-8 oil consumption. Oil consumption has never been a problem for me on the RX-8 or earlier rotaries. On the RX-8, changing oil every 3K I have never needed to add any. Like SWOOPE, the add point on my RX-8 is usually between 5K and 6K. Yes, the oil level continually goes down but Mazda designed in a decent reservoir so you don't notice it unless you are determined to keep the oil topped off,

I was also one of those low mpg believers who though I averaged 14-15 mpg. Almost all my driving is in-town. I finally entered the data for the past 28 months and was surprised to find my average is more like 16 with several 3 month periods of 17 mpg. Since hitting 15K miles and getting the R flash it looks like it the 17 mpg is here to stay. The main thing I learned is that you can't judge you mileage (either way) from just one tank.

I guess what I am saying is that I believe both the RX-8's oil consumption rep and gas mileage rep is based in perception. That is people get the car with the preconception of minimal oil consumption (as with many piston engines) and a low of 20 mpg (from the big print on the factory sticker). When the expectations aren't met the issues then gets exaggerated.

IMHO of course.

JonsToy

"If you read the instruction manual, the shifting for normal driving is quite intensive. It's almost every 5 to 7 miles per hour. I actually try to follow this but it is very hard. It is possible that people are driving the 8's as a 5 speed with an overdrive, instead of a 6 speed. "

I think you'll find very few MT owners actually follow these shift points. Doing so might indeed save on oil usage and improve gas mileage, but at what cost?

I normally shift between 3500-5000 rpm, and in my opinion this allows the car to show some 'spirit' as it accelerates. This is a sports car, for goodness sake! If it means I have to add a half-a-quart of oil every 2000 miles and only average 16-17 mpg in the city, then so be it. Such is the price I've accepted to pay for driving excitement!

Tirminyl

The relation between the two is that people can't keep their foot off the throttle. So, you should expect bad gas mileage, and excessive oil use if you beat it everyday. Ya gotta red line that r074ry!!!one.

EyeBall Fixer...(o)(x)

My Case with an 04 AT:

I drive 90% in town under 40 mph.
I've tried shifting at the beep = 11 mpg.
I''ve tried granny shifting which =11 mpg.

I get it out once a week and drive it at 75 mph to clean out the carbon build up
and "power brake" to stop my front pads from squealing.

I use a pint of oil every other fill up.

This is the only beef I have with "my" 8.
I just wish I got better MPG's then my friends Viper.

spieder

If you're driving it conservatively, getting 11mpg and you are using that much oil there is a problem somewhere. You are basically consuming 5 quarts (your entire engine oil) every 1800 miles.

Nubo

It's difficult to compare situations because the oil metering varies by rpm. If I'm just commuting, there is a lot of stop and go, mixed in with some high-performance accelerations and high-rpm driving, to try and blow out carbon. Both of these modes seem to be hard on mileage and oil consumption and I'll get maybe 1000 miles on a quart and 15 or even 14mpg. On the other hand, I've cruised 1400 miles on open highways and used only half-quart of oil and gotten 24mpg. It's hard to judge "mixed driving" and "city driving" because everyone's definition and habits in those modes is different. For a more accurate set of variables, try a couple of tanks with cruise-control on an open highway. You might be surprised.