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-   -   Saving Gas (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/saving-gas-1008439/)

iwantarx7! 08-15-12 09:45 PM

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

RotaryEvolution 08-15-12 09:56 PM

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.

REAmemiya_fan 08-15-12 09:59 PM

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.

beachFC 08-15-12 10:22 PM


Originally Posted by REAmemiya_fan (Post 11190134)
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:

RotaryEvolution 08-15-12 10:25 PM

get a geo metro if you want to save gas.

RotaryRocket88 08-16-12 12:54 AM

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.

7speed 08-16-12 01:14 AM

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.

misterstyx69 08-16-12 01:40 AM

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!

beachFC 08-16-12 02:37 AM


Originally Posted by lambof.god (Post 11190297)
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.

exactly.. :nod:

Hernan1209 08-16-12 03:27 AM

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

iwantarx7! 08-16-12 03:41 AM


Originally Posted by Hernan1209
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

misterstyx69 08-16-12 07:15 AM

$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..!

jimmydanny 08-16-12 07:29 AM

$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!

clokker 08-16-12 08:11 AM


Originally Posted by RotaryEvolution (Post 11190173)
get a geo metro if you want to save gas.


Originally Posted by RotaryRocket88 (Post 11190287)
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.


Originally Posted by Hernan1209 (Post 11190347)
If you want to save fuel get a Prius. By the way, it hurts to write that.

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.

REAmemiya_fan 08-16-12 08:42 AM


Originally Posted by clokker (Post 11190444)
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.

Aaron Cake 08-16-12 09:15 AM

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

RotaryEvolution 08-16-12 10:59 AM

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.

RotaryRocket88 08-16-12 05:57 PM


Originally Posted by clokker (Post 11190444)
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.

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.

Derekcat 08-16-12 07:18 PM

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


Originally Posted by Aaron Cake (Post 11190487)
Look up the EPA highway estimates for the 12A lean-burn 1st gen and prepare to be shocked.

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?


Originally Posted by Aaron Cake (Post 11190487)
Prius? Bah, terrible mileage. I drive an Insight. :D

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

KNONFS 08-16-12 07:39 PM


Originally Posted by RotaryEvolution (Post 11190574)
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.

Again ^ THIS!

j9fd3s 08-17-12 12:05 AM


Originally Posted by Derekcat (Post 11191110)
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?

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...

Derekcat 08-17-12 12:23 AM

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..

j9fd3s 08-17-12 10:32 AM


Originally Posted by Derekcat (Post 11191386)
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...

kel 08-17-12 03:19 PM


Originally Posted by misterstyx69 (Post 11190310)
[...]....Drive it Like ya stole it!


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 -

Tem120 08-20-12 02:21 PM

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


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