Saving Gas
 

I heard if I stay in 3r gear, when driving City street a (3k-3500) saves more gas. Is this true? lol.

no

some people think staying below the injector transition point will save fuel. in some cases this may be true, in most it is not.

I get best mileage shifting between 2250-2750. Sometimes I go to 3-3500 if I have to be quick. I average 19.8 mpg combined. That's S5 NA.

i shift between 3.5-4k(random redlines) and average 18mpg(streeported, no o2 sensor, staight-piped, fireballs.. the works) :scratch: i just can't stand grandma driving

if i did what you did, i'd probably get ~22 :scratch::scratch::scratch:

get a geo metro if you want to save gas.

I laugh every time I see a thread about conserving fuel with a rotary. City mileage will always be poor; even with excessive short-shifting. And if the area you live in has a lot of hills, forget about shifting below 3-3.5k.

The last thing I ever think of is fuel mileage. Owning a 7 isn't about saving money, I thought everyone knew that before buying one. I have no idea what my mileage is and I've never bothered to keep track. These threads always pop up but really are meaningless

I did get 400k's to a tank once. But normally it's 275-300 of pure enjoyment.

I saved Gas in my Rx7 Once..then I got out and Farted like a SOB!.
Save Gas?..Hug a Tree!,kiss a Beaver!, Koom By Yah!....Drive it Like ya stole it!

exactly.. :nod:

If you want to save fuel get a Prius. By the way, it hurts to write that.

lol.

Well, a friend says Rotarys waste the most gas when you're starting off from 1st in traffic, red lights ect. He said once the 5th & 6 ports open just cruise at like 3-3.5k in 4th saving the most gas.. idk. Ofcourse everyone doesnt care about gas with a Rotary but gahh damn 4.00 a gallon I'm trippin right now lol

$4 a gallon?..try UP here.you are paying $5 and up.(1.25 a litre X 4.1).
It's a "given" you are going to consume gas if you have an Rx7.Really any car for that matter.they like Gas for some odd reason,so just face the fact you are gonna pay to play.
If you Drive like a Nascar Pro or a Granny will determine your MPG.The cars were meant for High Revs and seem to enjoy it up there though.Besides how you gonna keep the internals clean if ya don't get the Revs Up and blast out the Carbon?..cough,heh,heh,cough..!

$4 a gallon? $5 a gallon? Boohoo. 1 gallon is 4 liters, we pay 15 NOK per liter, one USD is 6 NOK. So we pay around... 2$ per quart. Try to live with that!

And as lucky as I am, mine "only" uses 23mpg on mixed dry/wet/snow/ice. Maybe 24-25 on sunny days like we have so many of in rainy Norway!

I disagree with the mindset here.
Sure, the rotary will always get horrible mileage relative to newer cars but what's wrong with maximizing fuel consumption?
No one seems to have a problem with improving other areas of the car's performance, why is this aspect so different?

If, like me, you daily drive your FC, "drive it like you stole it" is not a reasonable option. I enjoy the opportunities to let the car run but really, shifting at redline is silly when speed limits run from 30-45 mph and you just want to get to work.

If you've narrowed the focus of your ride to track car/canyon toy, that's fine and I can see how mileage is of little concern.
However, if you're trying to keep your car viable as an all round form of transportation, then even a couple mpg is as big an "upgrade" as say, a new Koyo rad or Hawk brake pads.

That said, in my experience, 16-18 mpg is about as good as it gets in city driving and 26 is the best I've consistently gotten on the highway, so the 7 will never be an economical car from a fuel consumption standpoint.
Still, there have been times when an extra 30 miles left in the tank made all the difference between getting to work on Friday and walking, so a couple mpg can be a lifesaver.

This.

If you want to save fuel, you need a properly tuned standalone.

Case in point...just tuned a Haltech P1000 on a street ported single turbo FD. Owner reports 32 highway MPG on the way back to Toronto. I'm certain I could eek out a little more by observing how he drives long term and adjusting closed loop to work with him. Don't know about city mileage and honestly wouldn't take his experience as a test case since he's always hard on the throttle around town.

The stock ECU is pretty bloody crude. A modern standalone running observer based with 100% O2 correction in vacuum can achieve impressive damn results.

Look up the EPA highway estimates for the 12A lean-burn 1st gen and prepare to be shocked.

Prius? Bah, terrible mileage. I drive an Insight. :D

never said you can't get decent mileage with a rotary but if you live in the city forget about it, that is the blunt truth.

open highway? yes, you can do ok. no amount of tuning will ever make a rotary not be thirsty every time you take off from a stop or idling.

Highway mileage is a different matter entirely, as it's generally easy to just cruise at one speed. This conversation is no different from what you'll find with any car; except for the rotary's lack of low-end torque, which means you have to drive it differently in the city.

The reality of the matter is that the difference between driving like Grandma and driving to enjoy it will net you virtually no difference in city mileage. It doesn't mean you have to redline every gear, but bogging the engine in a near-futile attempt to get 1 more mpg is the wrong approach. If you drive 10,000 miles a year, average 20 mpg, and pay $4 a gallon, the difference is about $8 a month for 1 more mpg.

+1 Clokker
I feel that fuel economy can be a reasonably good general indication of the health of my car's engine/related systems.

Where might I find the lean-burn 12A stats? Fuel economy.gov doesn't report anything before 1985.. Though they had an old file that lists 17/18 MPG for a 79' FB. But shouldn't the Thermal Reactor kill the economy in those anyway?

That's the spirit! I always laugh at people buying a Prius... When they could get similar fuel economy [or better] in a number of [much] cheaper ways. XD

Again ^ THIS!

the lean burn engine was introduced in 1981... the previous thermal reactor engines needed to be rich to not misfire, and to keep the reactor working. Mazda claimed a 20% improvement in mileage, but i'm not sure how they measure that. the actual mileage in the car is about the same.

i've actually owned a mint stock 79, and it would get 23-25mpg on the freeway, totally stock. my 83 LE would get 20-22, the T2 was like 18-20 with the 13BT, and 16-19 with the 20B (although if you use the gas pedal the 20B goes single digits in a hurry), the FD got 23, and the Rx8 gets 16-22...

so in a sense the rotary is kind of cool, you can have big hp in a 2 rotor and it gets the same mileage...

Ahh interesting! I was thinking that he meant leaner than the catalyzed setup.. Though its pretty strange you didn't see better mileage in the 83'.. But I do remember running out of gas in my old 83' on the freeway... ^_^" Gas gauge was sometimes bad and I expected more on the trip meter..

nope they made a bunch of small changes to the engine so they could run it leaner so they could use a cat...

Hear Hear! Was recently told that some pansy RX8 owners were getting premature engine failure from not hitting redline enough.

Ya ain't livin' if you don't hit at least 7000 daily.


(btw, here's a funny one. Had a tree-hugger get apoplectic over the wife's SUV and how much more responsible I was to drive a small car. The wife's X5 gets 7mpg better than me)


- k -

I use my Power FC injector duty to see what gear has the lowest

I've been playing with my tune for a while now , and i'm getting.. decent MPG's

in the 18-20 concidered I was getting 8 MPG's when I first got the car this is a big improvement LOL

now I read alot of threads about the rotary running rich ..

maybe this is more a technical question .

sorry for hyjacking this thread LoL

but do rotaries get bad MPG because they NEED to run rich in order to stay cool , and almost never being in stoich ..

or is it because more air flows inside the motor then a regular engine and to maintain ideal A/fr's it requires more fuel than a comparable reciprocating engine

thats happened to me a couple of times . LoL I tell them its a 1.3 OH the MPGs must be AWESOME ! .. I go eehhhhh .. no

its both. kind of. the engine can be run really lean (at lower loads), its the cat that needs to be rich! the cat can't run lean, and it cant run over 650c, so the stock map is rich. some piston engine cars are like this to varying degrees too.

the rotary also moves a lot of air, and due to the long seals and long strokes (270 degree vs 180 degrees) there is a lot of time and a lot of places for compression leakage

my cats gone LOL

yes, but the ECU doesn't know that!

lol I ahve an after market ECU that I tune myself for hte most part my A/fs will stay between 14.5 amd 15 in my cruising speeds and during light throttle acceleration

I average about 22mpg on a not so stock anymore N/A, just have RB cat replacement set and catback, a Jacobs Rotary Pro Pack ignition, Taurus alt, and 3rd gen pump. It's my DD 5 days a weeks for college and don't usually drive any other time, no money, and I usually Granny around my home town, 55mph on the interstate, and usually get in one or two 5-6k runs through 1st and 2nd then a couple miles to cool down before parking at school.

Oh, almost forgot, just pulled air pump and acv yesterday so I don't know how/if that will affect mileage.

I've gotten 24 mpg my last two tanks. shifting before 3k rpm and trying to just do more coasting in gear than braking, keeping smooth gear changes, and using 5th gear a lot lol. I think a lot of it comes from patience and looking at your bank account after dumping a few tanks.

Wow. City, or highway?

- k -

it's about 60% highway and 40% city. mostly country back roads at 55 to 60 mph. then a little ways on the interstate at 70 mph. I removed my airpump and the compressor blew up on the way to work the other day so I cut the belt off. So there is less resistance
on the motor, but I like to think it's just better driving habits and using mid-grade gas
from the same station by my house. Also I drive a '91 vert.

I'm impressed. Best I've done is 22 on highway - Interstate - from Montana to Denver. City for me is closer to 16. Hope to do better when repairs and final tuning is done next week.

my 23.5MPG figure(330 miles/ 14.25 gallons) was taken at an average speed of 80mph. i could never stomach driving 55mph for a full tank and i never noticed enough of a discrepancy between 55 and 80 to ever attempt it. 4th or 5th also made almost no difference because 4th offers less load but higher revs, 5th is lower revs but higher load and the VE of the rotary is more efficient at higher revs unlike many boingers which are more linear(lugging the engine in higher gears doesn't necessarily net better mileage). non turbo vehicles i could imagine would see an actual difference since 5th is geared a bit higher than my TII, i have never tested our S5 GXL on long trips but i don't believe it ever got over 300miles to a tank and the tank is larger than my S4.

the 55mph figure you see listed many places is a generic rule and doesn't apply to every vehicle. the FC is light and actually very aerodynamic(look at the land speed record holder FC with stock body, it is only lowered but has a full underbody tray. the FD was less stable than the FC at the same speeds) which translates to less drag at higher speeds. if the engine is tuned well at all RPM/load ranges you shouldn't see much difference at higher speeds.

removing the catalyst increases flow in and out of the engine, which actually can increase your mileage(you can also lean out the fuel trims since you do not have to run rich to save the catalyst). i am not advocating removing your cat though, the only vehicle i run catless is my TII because it feels like an 80 year old with arthritis when i put the cat on it(boost is already laggy with the non BB 70 trim turbo and 8.5:1 rotors, with the cat on the power band is so narrow it's almost useless).

I think it's a little weird that I get 18 consistantly, driving fast, slow, freeway, city.. Nothing seems to make a difference hahaha

Yea, when I brought this S4 GXL out of a 10 year retirement it only got about 12ish. I like to think that everything had to wake up and stretch their pintles, seals, and whatever else that was likely sticking or lagging behind.

Can't wait till I 'Squirt her, grab a TII trans, and 3.9 rear which should almost cancel each other out in terms of running higher/lower rpms at a given speed, but give me something a bit more bullet proof through my hard shifts. Then I'll probably see how high I can get my mileage. This is my DD and I'm a poor college student so it may take a while unfortunately.

Highest I've gotten yet was 13, almost all highway, with (3) 1minute auto-x runs. That was NA, and its a S5 HBP engine with 9.4:1 comp. I just got 13.5 with mixed driving after I slapped a 20G kit on it. It's nice not having to downshift to accelerate up slight inclines at 55mph.

shift when the light tells you to to get the best fuel milage... its a rx7 dude you wanna play you got to pay