What do you N/A 2.5L drivers get for MPG???

Wondering cause I've always thought mine might be a tad low, even considering the 2.5L and AWD and driving style.

For quite a while I was getting 18 - period. Now I get a pretty rock solid 20-21 mpg (not sure what changed). That's 17 miles commute to work down 35W not during rush hour and lots of "errand running" type trips. I drive quite spiritedly (but certainly not WOT all the time).

Long highway trips I see 25-ish - maybe a hair more.

Anyone else care to share what they get?

 

Eek. That's way low, man. I'm on my second 2.5L NA Impreza. I had a GC RS before and have a GG now. I've averaged high 20s (27-29) on both. More highway than in town driving.

If you're only getting 25 on highway trips, there is something amiss.

 

Good, so I'm not crazy.

The question I have then is why? Anybody got ideas why my gas mileage sucks?

Only engine mod I got is the SPT short air intake. Car is clean, well maintained, and runs wonderfully.

I throw a P0420 OBD-II code from time to time (usually happens at cruising speed on the highway after driving for 30 minutes straight, but only happens once or twice a month). Think I might have a very small exhaust leak right by the header-cat junction, which I've always assumed is responsible for that code.

So why the awful mileage?

 

my wife's stock '02 2.5rs automatic gets around 21-24mpg

 

Same here, on my stock 05 RS.

 

Suppose I forgot to mention AT.

sneefy: you got 5MT?

Would MT vs. AT = 5+ mpg difference?

 

honestly i have no idea what i get...gc with cai and a cat-back.

all i know is that it takes just under a half a tank to get to fs and back.

 

Huh, thats low...

Run some seafoam threw a vaccum line and dump some in your gas....that might help?

 

Actually, just Seafoamed about a month ago. Did gas, oil, and intake. I think that's when it bumped from 18 to 20-21.

 

Are your plugs good?
You check your tire pressure?
Hows the alignment?

 

Snowbum is on the right track I think.

Otherwise you could try some mods to up the MPGs:
Light weight pulleys: 1 or 2 mpgs
Complete exhaust: Varies
5spd Swap: I saw 7 or 8 mpg increase (EJ22Tim has a whole swap for sale right now, for a good price!)

 

^250 for everything you needs!

 

I get a little over 300 miles when my light comes on. That's with highway/local driving.

 

i get 27-29. i think dynapar and sneefy hit it right on the head.

my .02 is to try and keep you rpms below 3,000. i am not sure about automatic transmissions but i know us manual transmission guys have very short gears expecially when we get above 60mph. just try not to have such a led foot. and drive 60 on the highway. that will remarkably help alot...assuming you take snowbum's and dynapar's advise (you should do that) then reset your ECU, even after you start driving easier reset it because then your fuel maps will be reset as well.

 

Plugs changed when I Seafoamed - old ones looked perfect.

Tires I fill right about 40psi front and about 38 rear for summer tires (G-Force Sports) and refill if I see more than 1 psi drop (I check every couple weeks).

Alignment I haven't had checked since buying the car, but she seems to drive straight as an arrow on good roads.

Neat - the first two are on my list of mods to do.

Yes, yes - this I want, but haz no skillz. Anyone around here like to do tranny swaps and how much?

 

How far are your average trips? Having lots of short trips in the car typically kills gas mileage, especially in the winter..

 

Good point. Both of my Imprezas have been manual.

I always inflate tires to the max. printed on the sidewall. I do not exactly drive conservatively either.

 

Talk to ej22tim about swappin the tranny, i'm sure he would do it for a price.

As far as your bad mpg, I would try resetting your ecu. If that doesnt do anything then I have no idea wats goin on there.

 

O, and get your alignment done. There is a good chance that its off, even though it is not noticable in your steeringwheel.

 

02 Forester, 5sp:
stock tune: 21-27 mpg, depending on how I drove that week
I-Speed reflash: 23-26.5 mpg, 24.5mpg +/- 0.5 95%, 26.5mpg pure highway
I-Speed reflash/ intake manifold spacers: + 0.5mpg gains, so 25mpg average, unsure about pure highway, assume 27mpg

That's where I'm at so far. This is also at full weight and with 245 RE01R tires.

The reflash, or any aftermarket tune, improves consistency, never seen below 23mpg even in winter or in pure city driving.

I'm sure synthetic helps a lot in winter though, 0w30/0w40 + Amsoil SevereGear 75w90 in tranny/diff, very resilient to temp drops.

 

if you buy the tranny from Tim, i will be more than happy to help you with the swap. ive always wanted to do one.

 

Daily commute is 17 miles. If I'm running errands it's usually 5 - 10 miles. I always remote start and let her idle for a bit (usually till warm - 1 min summer and as much as 10 min in winter).

I was trying to gauge if my mileage was way under or not. Sounds like I might be a bit under average - but given my driving habits perhaps not terribly so.

Yeah, guess it can't hurt. I think I recall seeing somewhere that "Dave" or someone is the guy to see. (I'll search for the thread)

I'd heard intake spacer helps - thought I heard it shifted the torque curve downwards a bit too (any yay's or nay's on that?). Unfortunately, I don't think I have many options for tuning my ECU - like nada short of piggybacks or standalones.

Who stocks the Amsoil 75w90? I was looking for it last week at Checker's & O'Reilly's and didn't see it at either. Ended up buying some Lucas, which I'll return if I can find the Amsoil. (Anyone else have trouble cracking those 1/2" square drive rear-diff plugs? I swear my 1/2" rachet and breaker had way to much play side-to-side, couldn't get nothing on it).

What kind of time-line would we be looking at? Is it a single day project, weekend project, longer?

 

If you need something to help you with your driving style a vacuum gauge can do just that.

It's just something for me to look at while I'm driving to remember how certain variations in my driving affects my gas mileage.

my .01

 

idk we could probably get it done in 1 day or so. but you need to PM him and see if it would work first.

 

2000 2.5RS, 5MT, 70K mi, AEM intake, headers, Greddy catback, grounding kit, weekly P0420 CEL: ~28MPG hwy

2000 2.5RS, 5MT, 130K mi, Fujita intake, headers, Apex'i catback, performance sparkplug wires, no CELs: ~29MPG hwy

That intake of yours should improve mileage over stock, but have to cleaned the element lately? How old is it?

"Correct" tire inflation is listed on the door jamb, NOT on the tires. I think it's around 32PSI front, 30PSI rear. Overinflating by 8 pounds should theoretically REDUCE your rolling resistance (but hurt your traction a bit!), so I doubt that's the direct cause. Unless manufacturing variances cause a difference in overall diameter; having all the limited-slip hardware constantly active would definitely kill your gas mileage!

Your avatar looks pretty stockish, but do you have correct P205/55R16 sized tires? If you go bigger, your speedo will be off and you'll actually be traveling MORE miles than the odometer says you are. I don't think an 8PSI overinflation all the way 'round would have that dramatic an effect though.

You might want to get a transmission checkup though... the auto tranny wastes a little more power than the 5spd, but if your overdrive isn't locking up, it'd be wasting a *LOT* more power.

And sh*tty gas (w/ too much ethanol) requires more gallons to provide the same amount of power, so that's something to consider also.


Probably unrelated to MPG, but since you mentioned the P0420 CEL:
There's a factory recall on the "front O2 sensor" on some MY00 2.5RS's. I took mine in to Bloomington Acura Subaru to have done; it didn't cost me anything, but I'm not sure they actually did anything since it threw another P0420 code two days later. That's unlikely to affect your gas mileage though, in any case.

 

Right - more just trying to gauge how feasible it would be since it's my DD. For example, a two week project wouldn't be possible for me right now.

Wouldn't the correct pressure depend on the tire itself? I mean, a guy can throw a whole slew of different tires on that car and the same tire on lots of different cars. I guess I just assumed the tire was the deciding part.

My summers are actually 225/50 R16. So, it's just the slightest hair under stock in outer diameter. Wow. It just now hit me as I'm typing this that, yeah, it would actually give me the wrong mileage by a bit, but I think that's in the neighborhood of about 0.2%.

Would I be able to feel the overdrive locking up (or lack thereof)? I haven't cared much for that 4EAT since day 1 - wishing it had a tall last gear. At 70 mph I'm awfully close to 3k RPM.

 

I am curious of others have tried to pull the fuse and go FWD to save some fuel. I did some testing on my old Forester and I saw some improvements. Most of my driving is highway and I find that if I can keep it under 3k the better, sometimes going 65mph on 94W.

 

This is true. But IIRC the 4EAT has always gotten lower EPA MPG rating than the 5spd until the 5EAT came out. Also your car is not a standard automatic WRX. You have tuned it yourself for how you drive, and your mods. In theory tuning a car with more power (tasteful mods) would also yield MPG increases.

What kind of driving is your commute? all highway at 60mph? stop and go? city driving w/ stoplights? I drive 394/94 for 25-30 miles a day for my commute and then very little on campus. I noticed driving around down town that I got significantly fewer MPGs (2 less so far)

It took me 1 weekend to put in my 5spd. I did it all by my self (read no one helping me, besides on the phone). Having 2 or more people will make it go alot faster, especially raising and lowering the transmissions. If you have all the right parts and some good help, I would think that it could be done in 1 full day.

+1 for the vacuum gauge! Very useful in gaging how much throttle you are giving the car. You would be surprised how little throttle you need to give the car to maintain a speed, alot of people are over zealous with the happy pedal when its not necessary. -.5bar is where I normally cruise or below if I can find the right speed / situation (drafting, ect...)

You will know when the T/C locks up because you will notice your RPMs drop by about 500 while maintaining the same speed. It normally takes alittle while for it to happen. You probably wont notice it unless you are watching for it. Just chek your RPMs while cruising at speed when the car is cold and compare it to after you have been driving awhile.

A 5spd probably wont help you with your cruising rpms. I used to be right at 3k rpms at 70mph, now with the 5spd I am sitting at the same rpms. Both 4EAT and 5spd are a 4.11 FD. IIRC Tim's 5spd is a 3.90 which may lower those RPMs a bit, I am not sure.

 

I have not known many people to do this. The way I see it there are two main schools of thought with it.

1.) it completely dis engages the center clutch pack in the 4EAT and you are truly in FWD. (read: Safe)

2.) the center clutch pack is not entirely dis engaged and it is dragging a minute amount. (read: Smoking you clutch pack)

I have never taken one apart so I dont know which case is true. Putting the fuse in does something to voltage at the solenoid which controls the center clutch pack. I am not sure if it cuts it to 0 or if it maxes it out. either way, the true question is when the solenoid is all the way out (clutch as dis engaged as possible) is it dis engaged far enough to eliminate the chance of permanent damage. In the owners manual it states that the FWD fuse should only be used for distances under 10 miles. This could be because Subaru didnt want people dorking around with the car in FWD, or it could be because there is the possibility of causing lasting damage to the AWD system.

 

I get 23-24 in town, and depending on my speeds on highway driving I get a tinch over 30

 

Highway, non-rush hour - couple of stoplights. 35W N, 36 W, Snelling N.

Okay, I was actually going to ask about that. Good info. Thx

Actually, I had something in mind that I feel when I drive that I thought might have been the overdrive and that's exactly how I would've described it. Almost like a subtle shift into a slightly taller gear. Only happens when I'm light on the pedal holding speed and it jumps back up with very little throttle increase. So, I would say yes, it is locking just fine.



I'll have to go review that FS thread and think about it, check the bank account, etc. MT swap is something I thought about from the beginning, but figured it would be out of reach for a while. Maybe not. :yumyum:

 

i got an 02 rs with a cat back and cai.. im lucky if i get 20mpg

 

Yeah, torque curve drops 200-300 rpm, but these lower rpms is where you are most of the time driving around. Top end didn't really seem to suffer either. I auto-x and rally-x my car, and I have a particular desire to improve bottom end power as one is rarely staying in the upper power band, that and any efficiency that improves low and midrange torque improves driveability and mileage. Whenever I get around to finally getting an exhaust done, it till will be geared for low and midrange power.

Fleet Farm sells Amsoil. They have Severe Gear tranny oil and the long life motor oil, but that's it. They don't carry a wide variety. If you want something specific, look for local dealers.

 

Cool - that torque curve shift is why I've got it on my list of mods to do (that and it doesn't sound tough to do )

Searching turned up that Cheetah Auto in Roseville used to carry Amsoil, too. They're right by my work, so I'll check em out tomorrow.

 

wow.. my 05 auto gets 30+ on the highway. i averaged about 34 on the duluth cruise and still had fun

 

my 98 gets 26 city. I use it to deliver pizza so a lot of stop and go too. otherwise I get about 29 or so driving to duluth. I also have a check engine light on right now too. I used to get 30+. As for mods i have cai by injen and a custom equal length header back. Its a manual. I also am running stock wheels right now. hope that helps a little bit.

 

I get 25-26 DDing it, 27-30 highway. Obviously, my daily commute is mostly highway, and Fargo traffic is very light.

the 420 CEL is a cat inefficiency code... it might be that leak, it might be your rear O2 sensor, or it might be a clogged (dead) cat - how many miles on your car?

 

I can't answer your poll because it really depends on a lot of things. definitely you are on the very low end.

highway
- If I cruise at 70mph or less with at most 2 ppl on the car I get 34/35mpg, if I go 75mph then it goes down to 30-32

- city driving sucks, maybe around 21-23 with some above 3k rpm shifting.


I just have few mods: perring light pulley, borla catback.
if your trunk is full of heavy stuff that cuts down a few mpg.

I have not noticed any big change by using different gas brands.

 

I wonder what kind of difference in mpg you would see going from a 2.5 rs to a forester?

 

If you get a chance to drop the cat out of your car, shake it and see how much it rattles. When I pulled mine out a while ago, it sounded like a box of rocks, and when I tipped it a whole bunch of chunks fell out. The catted had suffered a complete melt down. Most likely from teh absurd amount of fuel I was throwing at the car on the low end to boost low end TQ (tuning w/ PP6).

 

80k - bought it with 66k in December.

Oh yeah - so add about 120-150 pounds of stereo equipment + sound dampening, though it's most often just me in the car - so it'd be like driving around with the GF in the trunk all the time.

Well, if the guy on Nasioc hadn't just sold his heat-wrapped borla headers out from under me I'd have that opportunity. Will definitely check if the opportunity arises.

Will PM you if Cheetah doesn't have what I need. I'll be looking for ATF to do a tranny flush and 75w90 for the rear-diff.


Another gas question, then. I was told by someone I trust for car advice that if my engine doesn't need higher octane gas (and the NA apparently doesn't) that I'd get more power and better mileage out of a lower octane gas with stock ECU & tuning. Is that accurate or no? I was running 92 until he said that and 92 hit $4 a gallon - then I switched to 87 and reset the ECU. I don't recall any noticeable change in power or fuel economy from the switch.

 

Unless you've modded and tuned for it, 92 would give no benefits over 87. Higher octane fuel is a knock inhibitor, there's no extra power inherent to burning it, but you can tune wilder before you run into knocking on it.

 

Cool - thx for the answer, glad I can stay with $2.94/gal 87! :hsdance: