Gas mileage.. I feel too low.

The car is reading 13.5mpg for my city driving. I have a 5EAT tranny, a 1200 mile new shortblock/turbo and use 91 octane. What am I doing wrong? My brother drives an '03 WRX stg.2 (I think?) and gets better mileage than me. Is it the new block not broken in yet? I drive like a granny and am now testing it in full automatic mode rather than the manumatic. We do have a good amount of hills here in NE PA but would that kill my mileage?

 

 

Just seeing what you guys think. Maybe i'm just worried too much or my average mpg gauge is off.

Usually the gauge reads .25-1 mpg higher than what I actually get calculating the old fashioned way. I usually get 16-17mpg in mostly stop & go driving, can go as low as 15 in the winter.

I don't see any difference between 92 or 93 octane - not that I was expecting any.

yea that is weird. Thats what I get when I drive like an asshole. Try maybe resetting the ECU? Then go on a 10-20 mile highway roll at 80. Put on the EST MPG and it should read about 20-25 or so(just set cruise) this might fix the problem.

that is indeed low, unless you drive like a maniac or all uphill drive?

 

but AFAIK, stage 2 tune gets you slightly better MPG

Try the reflash or maybe have a tuner go along for a ride and make adjustments.

my commutes from cleve to philly are like 26 MPG (no cruise control) but in the city jacking around or hypermilling I get the same 17-18 mpg. Manual mode 4th gear hold under 40 mph same thing.

I'll definitely try some of the things you guys suggested. In no way do I drive like a maniac lol. I'm boosting sometimes but very mild. I've never even gone WOT and drove my previous '95 Legacy LS harder!

I've never even gone WOT

 

thats a shame, shouldve gotten a 2.5i

Not tryin' to beat on the new block/turbo just yet.

im getting 22.5 average and thats 90% highway driving, setting the cruise control at 75-80 mph.

No need to floor it for me. My tune is set almost half throttle you will go from 50 to like almost 100 never getting past 4k rpm. People who drive my car accidentally go way too fast all the time.

I am getting about 24-27 on my display 75% highway.

do you also let your car idle for long periods at a time also ?

 

the steep hills can have an effect expecially with an automatic tranny. the higher load makes the tranny shift later reving more and sliping more on the torqueconverter before it has a chance to lock up.

im getting 22.5 average and thats 90% highway driving, setting the cruise control at 75-80 mph.

 

Just a little lower than my average (~23.5mpg) with about the same driving conditions.

 

13 is LOW.

 

When was the last time you did normal maintenance? Things like spark plugs, air filter, oil, coolant, trans/rear diff fluids? Do you have a tire low on air?

I get 23.7-24.1 consistently and my drive starts @ 9200ft. goes down to 5300ft and back up almost daily. I also find that if I keep my car in it's powerband I get slightly better gas mileage then if I drive like a granny and let it drop under.

05 5eat Stg 2

 

I am also at 15 mpg mixed.

 

Given that I almost everyone get at least 18+ for stage 2. I am looking to issues with o2 sensors. There are thread on NASIOC where bad o2 sensors or maf sensors make the car run rich, and significantly lower MPG.

i get 18-19mpg and that for 1 hour stuck in traffic everyday

If you are stuck in traffic in hilly country the torque converter will waste a lot of energy. On flat ground not so much.

 

Best way to get fuel consumption is to find a long road that's reasonably flat, drive that stretch at a continuous pace like 55mph and then have a baseline for fuel consumption. What you get should be close to the official fuel consumption value. (+/- 10%) Weather will of course have an impact - cold weather increases the consumption, rain too.

05 5eat Stg 2

 

I am also at 15 mpg mixed.

 

Given that I almost everyone get at least 18+ for stage 2. I am looking to issues with o2 sensors. There are thread on NASIOC where bad o2 sensors or maf sensors make the car run rich, and significantly lower MPG.

 

Stage 2 Cobb or a legit road/dyno stage 2? I had a generic e-tune and I ran rich enough to eventually fry the up o2. People could see/smell the unburned fuel behind me. I could wash the car and after 15 miles my bumper was Honda civic black. After a real tune(open source in my case), my mpg increased. Well... after my new found power and 1/4 times set in and got old. I also use maf cleaner when I change oil and clean the air filter. Kinda every 3rd oil change and reset PCM while I'm at it.

What is the PCM ?

 

I wish I had a way to test, how clean my exhaust is in terms of unburnt fuel, without risking failed state inspection notice.

 

Ill clean the MAF, and maybe get the o2 sensor replaced anyways.

http://en.wikipedia.org/wiki/Powertrain_Control_Module

 

General idea @ least for a WiKi.

 

Disconnect negative and leave it off the entire oil change/air filter cleaning process. Meen mixed reviews on the speed up the learning by 3rd gear 2 psi brake tq so won't post the nasioc link.

Got 9mpg on an 07 STi. Protuned at 110 degrees a few mods later and 30 degree weather made this number so poor...

Wow, I feel way behind here. To answer a few things I found.. The car has 140K on it. We just put a new short block and turbo in about 1300 miles ago. The oil filter has been changed, oil has been changed once (not synthetic just yet) and other fluids have also been replaced. Could my O2 sensor be bad and not throwing a CEL? Should I redo all the fluids again just to make sure? I just about filled it the other day (probably about $5 from full though), reset my trip b, and left it in full auto mode the whole time. Just checked tonight, about 100 miles later, and am now getting 12mpg. Something is so off and it's really bothering me. I do have an auto start, letting it run about 5 minutes before I get going but that's it!

 

Someone, anyone....help!!

Autostart and 5 minutes idle consumes a lot of fuel.

 

Do a controlled condition test first.

 

1. Warm up car fully by driving 15 to 20 miles. This will maake sure the transmission is warm too.

2. Fill tank. Remember which pump and gas station.

3. Drive a decent distance 60 to 100 miles at constant speed on flat highways, avoid areas where there are hills.

4. Return to gas station and fill up at same pump.

 

This shall give you the best consumption value, which should be around 25 mpg give or take 2 to 3.

 

If you are below 20 in his test you do have a problem.