Falken

The speed limit on lake shore drive, my main road, is 45MPH, but I usually cruise at around 55 and 3500RPM. Should I not be cruising in 5th? Sorry I'm a beginner, but I thought that 6th gear was meant for overdrive or interstate use when I would be cruising at 80 or so (just like everybody else).

I used to drive a BMW 325i which shifted nicely at 2500RPM and cruised around the same speeds. I always assumed because it's a rotary that there were RPM "equivalents", and the equivalent of the BMWs 2500 seemed to be the RX-8's 3500. Its like I kind of have a table of equivalencies in my head. I expect someone is about to tell me that the two types of engines are incomporable when I comes to RPMs, and that equivalencies are incalculable between the two, i.e. apples and oranges, right? In any case I felt like if the BMW cruised efficiently at a certain RPM than I could afford to keep the RX-8 significantly higher without wasting fuel or causing excessive wear and tear.

Is that wrong? Should I be holding the rotary at or below 3,000 when cruising??

EDIT - I should note another habit I have while driving that I wonder if is causing problems. I very rarely brake without the clutch in...my mother has cursed me for it because I know it wears out the clutch but that's just the way I learned because I am too afraid to drop below good RPMs and into stall range.

Whenever I approach a red or a stopsign, the clutch goes in, and I put it in first without releasing the clutch well before I come CLOSE to stopping. Than I just take off in first when the light changes or it's my turn at the stopsign. Nasty habit that's causing problems??

a-spec fd

My last tank of gas was the best mileage i've ever got in my 8. 21.1 mpg! I drove about 85% highway 15%city. My worst ever was after the drag strip at 14.2 mpg.

Rems31

the higher the RPM, the more gas it burns...for any car, rotary or otherwise...

you should try to break that habit. Let the car slow down by itself before applying the brakes. You'll easily find out the RPM for each gear when you start to bog down the engine. And I don't know what the harm is braking while in gear. That's like saying you wear out the clutch by giving it gas and driving it

Georgia8er

You're trying to develop a driving style that is like doing a math problem: if you have X situation then do Y. It has nothing to do with different cars you have driven being "equivalent" it's about learning to actually drive instead of being an automaton in the driver's seat. Driving has more to do with feel than anything else, if you want to be a good driver.

If you are going 55, then yes there is no reason for you to be in 5th gear unless you are accelerating. If you are wanting more fuel economy then you always drive in the highest gear possible unless there is a reason (accelerating, braking, turning) that you should go lower. If you are driving along and see a red light ahead then you just take your foot off the gas pedal and brake when need be until you are a few hundred RPMs off idle, then you push in on the clutch. Not only are you using your brakes less you are using less fuel. I don't know that you will see big gains from that, but every little bit helps.

Rems31

I found the biggest gains to be not driving at excessive speeds on the highway and not shooting out of the line when the light turns green.

remy117

just about 18k

volk

To answer the original question, nothing is wrong with your car.

We all knew (or should have known) what we were getting into when we chose this car. Oh wait, this car chose me.

dozer

iTrader: (3)

so its better to downshift and rev the engine that much more than to not let it rev??

mysql

yeah, the car shuts off fuel when engine braking. at idle it's burning gas. in stop and go traffic if you do it properly, you can get noticeable results.

dozer

iTrader: (3)

^^^NICE!!!! thanks on the advice, this is my first manual car, and i live in souther california, were traffic is a must!

Rems31

you shouldn't even downshift...just leave it in whatever gear you were in. Then put it in neutral before it bogs. If you didn't come to a complete stop and the traffic starts flowing again, then downshift...

Groundrush

Interesting. I saw my MPG increase from an average of 17mpg (mixed city/highway driving) to 21mpg on my first tank of premix. After the first tank however, I have dropped back down to roughly 18mpg. Looks like premixing will end up with a +1mpg gain or so. Also to the OP...once summer blend gas comes online, you might see a slight increase in your MPG. Apparently winter blends cause a decrease of about 10% or so in MPG, though I can't prove that...just seen it quoted here a number of times.

delhi

How on earth does premix increase gas mileage? Also don't forget to add the cost of premix oil to the gas cost.

Groundrush

I'm not a Mazda engineer, so I'm just spitballing, but one would think that with better sealing ---> better compression ---> better burn --- > increased gas mileage?

All I know is that my driving habits rarely change, and aside from an occasional long highway excursion, my mileage has been extremely predictable for the last 2 years. The gain was quite noticeable after pre-mix. Not at all scientific, but a little too coincidental to completely write off.

andrew_RX8

iTrader: (2)

WTF?!?! Im getting only 145 miles to a full tank!! Well that could be due to the apexi SAFC II that im using...u can 'smell' my car from a mile away thanks to it running rich...the problem here is that i bought my car from a dealer and it had the SAFC II already on it...i tried playing around with it but tuning it non-professionally is very hard to do! so yeah thats why im suffering with a 145 miles on a good day...i do have a heavy foot though! Any advice or suggestions on the SAFC II?

redlined_at_9gs

Ok I do about 95% city driving and I can get about 270 miles to a completely full tank...... However thats shifting at 3000 rpms every time and really boring driving with with only 1-2 redlines. If you are in a bind the 8 can definetly get 17-18 city (which isnt too bad for a sports car....... oh btw my car is completely stock (6 speed)

RedefineRX8

iTrader: (-1)

throw it away, it's a piece of ****.

Soapflake

Woops :p

quantum

Sometimes, I do 40 in 2nd. I don't even think about MPG.

robrecht

Shoot, when I want to hit the rev limiter, I go over 60 in 2nd.

robrecht

It depends on how fast you're going and whether you can coast a significant distance in neutral that you couldn't do while engine braking. Of course, this is not the fun way to drive a sports car but about once a year I see what the maximum mpg I can get on the highway with my lightened '93 Miata. Hit 40 mpg the last couple of years. Then I drive like I stole it to cure myself of the mind-numbing boredom.

Bastage

iTrader: (1)

I just finished a 2500 mile trip from FL to TN to NC and back. Most of the driving was highway at 75-85 mph, and on the highway I tend to floor it when I'm passing someone so they know I'm there (I'm still running the stock exhaust, so my car is !@#$ing quiet unless I'm in boost). I never got a highway tanks worse than 20 mpg (they were closer to 21mpg). I strongly believe that if I drove 65mph or less I could get close to the advertised 24mpg, but that would be boring.

During mixed city/highway driving the worse tank I got was ~18 (twice). These tanks included 1) runs through the Tail of the Dragon and 2) showing off the SC to my cousin in Greenville NC who just bought an RX-8 this past Saturday.

What I've gathered from the ten million gas mileage threads on this forum is that the RX-8's mileage can vary significantly from car to car, but mostly I think the way a person drives has the most to do it.

mysql

we've seen numerous rx-8 owners who've owned more than one rx-8 get completely different mileage numbers between the cars.

Normally I'd say mpg depends largely on the driver, but we also know for a fact that some cars cannot get anywhere close to 20 mpg no matter how you drive it. I've never hit 20 on mine, including when I was breaking it in and didn't go over 3500 rpm.

invasion08

iTrader: (7)

I hit 20-21 with mine

jdoo

My driving is about 95% city. My best tank was 14mpg. Last tank i got 9mpg. This tank I'm on track for 9mpg as well. I'm not even driving aggressively.

Thank god this thing is only my weekend toy and not a commuter car.