MPG Question

scuzzy · Post by **scuzzy** » Sun Jun 08, 2008 2:36 am

from a full tank of gas:

if I autocross on sunday: 20mpg
if I don't: 22-23mpg

car stats in my sig, I run relatively lean when I'm into the throttle (it's daaaangerous, but no knocking; I run 93 octane)

my commute is mostly interstate into work; 26 miles each way. usually stop and go but it's a mixup. some days are better than others.

RJ93SS · Post by **RJ93SS** » Tue Jun 10, 2008 7:47 pm

so what should the average ej22t be getting when it's properly tuned up and running well?

asc_up · Post by **asc_up** » Tue Jun 10, 2008 9:03 pm

I'm gonna say anywhere from 19-23 MPG based on your driving style.

yazmo · Post by **yazmo** » Sun Jun 15, 2008 6:02 am

i am doing like 280km for a 45 liter of fuel so i am like this guy who start this topic i got a very bad gas consomtion

im going nuts

ChesterKV · Post by **ChesterKV** » Sun Jun 15, 2008 6:23 am

yazmo wrote:i am doing like 280km for a 45 liter of fuel so i am like this guy who start this topic i got a very bad gas consomtion

im going nuts

Those numbers are foreign. What does that translate to in Freedom Units ?

.

Subaru_Nation555 · Post by **Subaru_Nation555** » Sun Jun 15, 2008 6:24 am

For some reason when my fuel gauge hits the "E" mark, it has only used 10 of the 15.9 gallons. I guess it makes it easy to calculate MPG. I get about 155-165 miles out of 10 gallons of gas in the city so roughly 16mpg. Pretty lousy if you ask me. Cruising at 65 brings about 23mpg.

asc_up · Post by **asc_up** » Mon Jun 16, 2008 12:55 am

I'd get a new O2 sensor if I were you. 16 MPG is extremely low.

ericem · Post by **ericem** » Mon Jun 16, 2008 2:24 am

Subaru_Nation555 wrote:For some reason when my fuel gauge hits the "E" mark, it has only used 10 of the 15.9 gallons. I guess it makes it easy to calculate MPG. I get about 155-165 miles out of 10 gallons of gas in the city so roughly 16mpg. Pretty lousy if you ask me. Cruising at 65 brings about 23mpg.

When the light comes on it tells you there is 10L left in the tank. Not a good thing to run your tank dry supposedly

So I am realistically getting only like 250miles per 50L with a N/A legacy. I thought that was good but I guess it should be able to get closer to 300-400 range! I think it's time for a o2 sensor.

Aerotech · Post by **Aerotech** » Mon Jun 16, 2008 2:39 am

Check out this simple test... it gives you a rough estimate of what you car *should* be able to achieve measuring the coastdown friction over a measured time.

http://unwiredtools.com/utcoastdown.asp

ciper · Post by **ciper** » Mon Jun 16, 2008 3:00 am

Couldn't you calculate exact MPG using the injector duty cycle and VSS1? The romraider logger does exactly this and its very accurate.

yazmo · Post by **yazmo** » Mon Jun 16, 2008 6:18 am

anyone have try this

Jet Chips Power Programmer

http://www.racepages.com/parts/performa ... ubaru.html

ZeroGF8 · Post by **ZeroGF8** » Wed Jun 18, 2008 9:51 pm

My gas tank leaks when it is above the half way mark (found out the hard way

), so I only put in 20L when the needle is just below the E. I average approximately 175km per 20L with 90% city / 10% highway driving which isn't too bad on a stock 325,xxx km EJ22T.

internetautomart · Post by **internetautomart** » Thu Jun 19, 2008 2:43 pm

ericem wrote: Not a good thing to run your tank dry supposedly

it's not good for a couple of reasons
1. the crap in gas settles to the bottom of the tank so that is what is left when you get down low (or something like that according to "conventional" wisdom)
2. if your fuel pump isn't immersed in gas it can run hot and burn out over time. that is why keeping over 1/4 tank of fuel is recommended for optimum fuel pump life.

Post by **Legacy777** » Thu Jun 19, 2008 6:47 pm

I've opened up my gas tank to get at the pump more times then I care to admit. None of the times have I really seen any "crap" in the bottom of the tank.

Plus, the way the pump is situated, it's going to pull the crud up regardless of whether the tank is low or not, since the pump sock is sitting at the bottom of the tank.

The internal flow of the fuel is what cools the pump/motor. Designers would not design it to need to be cooled by external fuel around the pump.

internetautomart · Post by **internetautomart** » Mon Jun 23, 2008 2:24 am

Legacy777 wrote:I've opened up my gas tank to get at the pump more times then I care to admit. None of the times have I really seen any "crap" in the bottom of the tank.

Plus, the way the pump is situated, it's going to pull the crud up regardless of whether the tank is low or not, since the pump sock is sitting at the bottom of the tank.

The internal flow of the fuel is what cools the pump/motor. Designers would not design it to need to be cooled by external fuel around the pump.

1st part you may be correct on, but the pump is designed to be cooled by the fuel surrounding it. That is why there are different pumps for in tank and external use.

Post by **Legacy777** » Tue Jun 24, 2008 7:40 pm

internetautomart wrote:1st part you may be correct on, but the pump is designed to be cooled by the fuel surrounding it. That is why there are different pumps for in tank and external use.

I'm not a fuel pump designer, so I can't say for sure, but I can't see the only difference between an internal & external pump is that the internal pump is designed to be cooled by the fuel surrounding it.

I agree with you that the pump will be cooled by the fuel surrounding it, but to say that you're going to get less longevity out of the pump because you don't keep a 1/4 tank of gas is a little far fetched. There are MANY vehicles with in-tank pumps with well over 100,000 or even more miles on the original fuel pump.

evolutionmovement · Post by **evolutionmovement** » Tue Jun 24, 2008 7:54 pm

I would think the difference would be the outside tank would be weather resistance and possibly a different housing that would allow it to draw a vacuum through a hose upon start up.

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MPG Question