rx7ofdoom

ok i've had the car for 3 days and its drinking gasoline more so than expected.. i've read up here are somethings i found i think a good price but i know you guys probably know the best deals and can think of something else im missing.

from rx7.com/store

NGK Plug Wire Set - 86-91 IGRCZE02 $29.95 $29.95
NGK BUR7EQ Plugs IGBUR7EQ $7.50 $7.50
NGK BUR9EQ Plugs IGBUR9EQ $7.50 $7.50
RP Aftermarket Fuel Filter - 86-91 FL900201 $25.00 $25.00
RP Aftermarket O2 Sensor FL900311 $40.00 $40.00

anything else?

also my future mods are going to be s-afc, intake of some sort and rb collected header rx7.com high flow cat and some sort of aftermarket exhaust either rx7.com dual catback or rb dual cat back.

IF you have any suggestions for me let me know...
the car has 82k miles just passed california emissions extremely easy!

THANK you in advance!!!

nubian

k, just so you dont go spend a bunch of cash for nothing... what kind of millage are we talking about, my s4 t2 gets 190-220 miles on a tank (16 gallon ). i just converted it from metric, if its easier, 300-350kms/60 liter tank.

if this is what you get, then you boost everytime you get in , on the highway at 65-70mph i can get 325-350 miles out of a tank. my car is i great shape with only 78k miles on it.

you have the right idea with an o/2 sensor and plugs/wires. check your wires for the resistance as spec'd in the fsm/hayes/chilton. if they are acceptable, you might want to think of a msd ign box instead, will steady the current and prolly help a little more than just new plugs/wires.

good luck

homebrewer

Well, it would help if you told us what kind of mileage you are getting. If you are getting in the high teens you are ok. If you feel you should be getting better fuel economy out of a 1.3L Wankel you're SOL.

rx7ofdoom

ok haha i know these motors get bad gas milage, im not exactly sure but the milage but i used more than an 1/8 of a tank going about 40 miles and its an 18.5 gallon tank? so thats below 20mpg i was driving about 70-75mph. I know its not that bad i guess but know it can be better so i want to fix anything that can be fixed.

redturbo

You are wrong about the tank capacity ,it is more like 16.5 not 18.5 .

staticguitar313

iTrader: (2)

no actually YOUR wrong s5's have an 18.5 gallon tank, s4's had 16.5, asshat.

rx7ofdoom

ok but as i was saying anyone have any places have better prices? or anything else i should get to help performance/ economy?

Syonyk

Sounds about right, I'm betting changing the O2 sensor will help it out a bit, since people tend to neglect those.

Also, 70mph is a bit slow for best fuel economy. Most people see better fuel economy around 80-85 with the windows closed.

-=Russ=-

rx7ofdoom

so your saying go faster for better fuel economy ingenious! haha i normally went 80-85 in my gti i was kinda sad thinking going slower would help

rx7ofdoom

oh also i was wondering what octane do i use? haha i haven't filled up yet but need to soon

JacKaL

well he did... 190 to 220 miles per 16 gallons.. 190\16 =11.875 220\16= 13.75 .. so 12 to 14 miles per gallon

TwinTurbineZ32

87 for n/a and 91 for turbo model.

coldfire

iTrader: (1)

there is no way that going faster will give you better gas mileage, it's a pretty simple matter of air resistance. i learned this in first year physics.
in fact, at higher speeds just going a little bit faster increases the power needed to overcome the air resistance, since the relationship is exponential...

anyways, there are some pretty basic things you can do for gas mileage.
as for the O2 sensor, i used to think it made a difference, but i don't think it's that much. i found out the other day my O2 sensor is not working at all. i am still getting about 600km to a tank.
regardless it's good to have a working one if you are running with the stock ECU.

also, maybe i missed it, but is this car turbo or not? if it is, then this type of mileage you are mentioning sounds reasonable, unless you are not getting into boost at all, just highway cruising.
if it's NA, you should be seeing about 20 mpg or so average, otherwise you have problems somewhere...

duffles

i just had REALLy bad gas mileage and found a scraped up fuel hose dripping only when the car was on. almost lost everything, luckily i found it before the my whole engine bay went up in flames.

MattB

dont be ignorant...people have proven that they get better gas mileage at higher speeds. the engine is simply more efficient at a certain RPM range


my 2 cents....
-Matt

Natey

iTrader: (19)

lol, Poor guy still never got a straight answer.

Yeah, that shopping list looks about right, IMO. One other inexpensive thing that people tend to forget about is the air filter. A new one's cheap and easy to replace.

aznpoopy

sparkplugs.com has those plugs for $6.40

ngk wireset for $21.62 or something weird.

rx7ofdoom

yahoo people answering questions. it has a new air filter and those look like good prices. Im not sure if this is true but i remember reading somewhere that you can get a universal o2 sensor for like $8 anyone know of this?
AND the car is not turbo its n/a

coldfire

iTrader: (1)

sorry, i'm just stating a simple fact. if you could post a thread or something where someone has actually quantitatively done a study on this, please do so.

it's totally possible that you may get better mileage at 80 mph compared to 70 mph due to mechanical reasons, i just don't see it as a way to get better gas mileage.

also to the person who started the thread:
if you are planning on getting an SAFC it will help you with gas consumption (you will be leaning out the fuel mixture to gain power) and you can actually get rid of/disconnect the O2 sensor. you can tune a low throttle cruise map, and you won't need the O2 sensor. actually it's probably a better idea to not use the O2 sensor if you are using SAFC correction, as i'm sure the oscillating closed loop ECU operation would be hard to tune with.
keep in mind it may only take you a month or so to make up the cost of the SAFC in gas savings if you tune properly

rx7ofdoom

ok, that sounds good to me , but im not modding just yet i have to sell my other car to get some $ to buy perforamnce parts.

d0 Luck

want good gas mileage? sell the car and get a civic.

Syonyk

*makes unhappy noises and starts posting*

The comment about going faster wasn't a general statement, it was a statement about FCs, specifically. It has been observed by many people, including Wayne (who is one of the most methodical testers around here, driving the exact same highway route to work every day), that a stock FC will get better fuel economy at 80-85 mph than at 65-70mph. The engine efficiency increases enough that it overcomes the increased air drag, and leads to better fuel economy. It doesn't appear to make sense, but it happens. My personal theory is that the only reason it stops getting more efficient around 85 is that the engine hits 3500 RPM and the stock ECU goes into a rather rich mode - with a properly tuned standalone, the most efficient speed may still be higher.

The O2 sensor doesn't make a big difference around town, but it does matter on the highway. Numbers I've seen indicate people get around 17mpg on the highway without the O2 sensor, 22 with it.

I'm currently running with a SAFC-II installed and the O2 sensor disconnected. Tuned slightly lean of stoich, I'm getting 20-22mpg highway. I'm planning to reconnect the O2 sensor this weekend and see if it makes a difference - closed loop will still be controlled by the O2 sensor, but the open loop mode that happens frequently in climbing hills will be leaner, and will help improve fuel economy.

The one big difference I've seen with the SAFC is that high RPM fuel consumption has dropped dramatically. I'm pulling out 30-40% up high, still running rich, and making good power. However, I no longer can watch the gas gauge drop while doing autocross or screwing around on winding roads.

I'm not convinced that a SAFC will pay for itsself in fuel savings any time soon. The cost ($250 or so) just is too high to make up in a few mpg, at least short term.

Another thing to consider is getting your injectors cleaned. Take them out, get them reverse flow ultrasonic flushed. They'll spray better, and you'll most likely see better fuel economy.

-=Russ=-

Natey

iTrader: (19)

an OEM 02 sensor costs about 65 bucks from the stealership, IIRC. A universal one costs about half that.

rx7ofdoom

ok here you go i drove less than 30 miles and used about 3 gallons and majority of that was highway at 60mph

Also i found an o2 for $18 on sparkplugs.com by denso
http://sparkplugs.com/more_info.asp?...92441&pid=1788

should work fine right?

rx7ofdoom

by the way your an idiot. My gti got over 30mpg if i wanted good gas milage id keep that. Im not an idiot i know rotary isn't great milage but when im geting 10-12mpg i think somethings wrong.