Welcome to the North American Subaru Impreza Owners Club Saturday October 25, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Subaru Models > Impreza Forum

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 04-20-2012, 12:21 PM   #451
nubsub
Scooby Specialist
 
Member#: 313575
Join Date: Mar 2012
Location: SF Bay Area, CA
Vehicle:
2012 Impreza 2.0i HB

Default

Quote:
Originally Posted by buran288 View Post
I just had the transmission re-flash done on my 12 Impreza as I was told it would improve the daily driveablity and reduce the somewhat harsh downs shifts that I had going down hill when taking my foot off the gas and coasting. Well yes no more of the harsh down shifts and my combination gas mileage has gone up from 31 mpg to 34 mpg BUT my highway mileage had gone from 36.7 to 31.5!!!!!!! Yes I'm going 65 to 70 mph but WOW!!!!!!!!! Oh and once it's done it can not be undone.
Just an heads up......
can you provide more info on this? what is happening to your instantaneous mileage when you are going 65-70 mph? what are your RPMs at those speeds?

it would seem that if they got rid of the downshifting when going downhill, you would getting better mileage since it would stay more in 6th gear. the only explanation i can conjure up (putting on my scientist hat) is that it's staying too often in 5th gear even when on flat ground...and so the way you are avoiding harsh downshifts, is to stay out of the 6th gear overdrive most of the time. (i know this is a CVT, but i'm just trying to simplify the idea of what "gear" your car is in while cruising on the highway).

OTOH, i have no clue how your in town mileage (or mixed driving) would get so much better.

what kind of mileage were your getting in "mixed driving" before the flash? what is your "average speed" reported by the computer on a tank of mixed driving? how many miles do you have on your car?

thanks for any clues i/we can use to see what happens with such a flash...
* Registered users of the site do not see these ads.
nubsub is offline   Reply With Quote
Old 04-20-2012, 12:25 PM   #452
nubsub
Scooby Specialist
 
Member#: 313575
Join Date: Mar 2012
Location: SF Bay Area, CA
Vehicle:
2012 Impreza 2.0i HB

Default

Quote:
Originally Posted by PAO56 View Post
just another update...with my Limited HB CVT, PVEZ approaching 11K.....with my commute of 53 miles one way Im now averaging between 31-32 MPG per tank now......it still seems to be slightly improving as we are entering spring/summer.........commute is probably 70/30 hwy city......with hwy spds between 50-75 depending on the stretch of road........
thanks, pao. glad to see how the car evolves as the miles accumulate.

what is the "average speed" that your computer reports on a tank of this mixed driving?

i'm becoming more and more convinced that while not perfect, the average speed gives a decent indication of relative highway and city driving in a mixed environment.

it's way too soon to see what my mileage will level out at, but i find that for my style of mixed driving (which amounts to an average speed in the low 20mph range), am seeing 29mpg on the computer. (will see what my next tank reads for actual mileage and i still need to check my odometer against GPS, too)

when i put my early miles of this tank on with more highway miles (ave closer to 40 mph, i was in the 32-33 mpg range).

of course, other factors like a lot of cold starts (like i have for my commute to the train station) really skew the mileage downward regardless of average mph...
nubsub is offline   Reply With Quote
Old 04-20-2012, 12:39 PM   #453
ocellaris
Scooby Specialist
 
Member#: 302559
Join Date: Nov 2011
Default

Quote:
Originally Posted by nubsub View Post
can you provide more info on this? what is happening to your instantaneous mileage when you are going 65-70 mph? what are your RPMs at those speeds?

it would seem that if they got rid of the downshifting when going downhill, you would getting better mileage since it would stay more in 6th gear. the only explanation i can conjure up (putting on my scientist hat) is that it's staying too often in 5th gear even when on flat ground...and so the way you are avoiding harsh downshifts, is to stay out of the 6th gear overdrive most of the time. (i know this is a CVT, but i'm just trying to simplify the idea of what "gear" your car is in while cruising on the highway).
The fuel injectors are closed when the car changes ratios (downshifts) to maintain speeds going downhill. Without this, you would hit the brakes at the bottom of the hill anyway, it shouldn't affect MPG.
ocellaris is offline   Reply With Quote
Old 04-20-2012, 12:57 PM   #454
nubsub
Scooby Specialist
 
Member#: 313575
Join Date: Mar 2012
Location: SF Bay Area, CA
Vehicle:
2012 Impreza 2.0i HB

Default

Quote:
Originally Posted by ocellaris View Post
The fuel injectors are closed when the car changes ratios (downshifts) to maintain speeds going downhill. Without this, you would hit the brakes at the bottom of the hill anyway, it shouldn't affect MPG.
oh, duh. you are right...the engine isn't doing any work here regardless...

(i had bought into the anecdotal evidence from some folks who said that by manually upshifting on those stretches, they were getting better highway mileage. regardless, i haven't experimented since i haven't had any real big trips with steep hills to check out this whole CVT braking issue)

aside: one thing i really haven't gotten used to with the CVT, coming from a 5spd MT, is using the brakes more to slow down the car. i regularly downshifted my MT to slow down. even at over 100k miles, i still had over half the original brake linings on front and rear of my old car!). i've considered paddle shifting downward at lights, but it's just weird and unnatural to me (although it should be easier without a clutch pedal). i wonder too if there is any long term reliability issues of using the paddle shifters regularly, as opposed to for occasional use.
nubsub is offline   Reply With Quote
Old 04-20-2012, 01:01 PM   #455
deanm11
Scooby Newbie
 
Member#: 303800
Join Date: Dec 2011
Location: Northern NJ
Default

Quote:
Originally Posted by ocellaris View Post
The fuel injectors are closed when the car changes ratios (downshifts) to maintain speeds going downhill. Without this, you would hit the brakes at the bottom of the hill anyway, it shouldn't affect MPG.
I think there's more to it. When you are in gear and under fuel cut/decel, the drag of the engine and drivetrain is slowing down your coasting. If you would make it down to a stop point all under decel, then there is no difference to being in neutral.. but otherwise where you will be back on the gas before stopping, Neutral (or less aggressive downshifting, equivalently) may be better, allowing you to maintain a faster speed than in gear with the drag. Somewhat of an offset while in Neutral is you are using fuel to at least idle the engine. The MPG indicator pegs at 99.9 even whlie in Neutral and fuel is being used to idle the motor though.
deanm11 is offline   Reply With Quote
Old 04-20-2012, 01:07 PM   #456
nubsub
Scooby Specialist
 
Member#: 313575
Join Date: Mar 2012
Location: SF Bay Area, CA
Vehicle:
2012 Impreza 2.0i HB

Default

Quote:
Originally Posted by deanm11 View Post
I think there's more to it. When you are in gear and under fuel cut/decel, the drag of the engine and drivetrain is slowing down your coasting. If you would make it down to a stop point all under decel, then there is no difference to being in neutral.. but otherwise where you will be back on the gas before stopping, Neutral (or less aggressive downshifting, equivalently) may be better, allowing you to maintain a faster speed than in gear with the drag. Somewhat of an offset while in Neutral is you are using fuel to at least idle the engine. The MPG indicator pegs at 99.9 even whlie in Neutral and fuel is being used to idle the motor though.
another good point if i read you correctly, the lack of downshift would give you higher speed at the bottom of the hill which means you will have less subsequent acceleration or need for fuel on the flat or uphill section that follows.
nubsub is offline   Reply With Quote
Old 04-20-2012, 01:12 PM   #457
ocellaris
Scooby Specialist
 
Member#: 302559
Join Date: Nov 2011
Default

Quote:
Originally Posted by nubsub View Post
another good point if i read you correctly, the lack of downshift would give you higher speed at the bottom of the hill which means you will have less subsequent acceleration or need for fuel on the flat or uphill section that follows.
This is true, and if people want to do that, they can click up on the paddles when descending. Most of the time I want to be going the same speed at the bottom of the hill.

Last edited by ocellaris; 04-20-2012 at 01:27 PM.
ocellaris is offline   Reply With Quote
Old 04-20-2012, 01:31 PM   #458
ocellaris
Scooby Specialist
 
Member#: 302559
Join Date: Nov 2011
Default

Quote:
Originally Posted by deanm11 View Post
I think there's more to it. When you are in gear and under fuel cut/decel, the drag of the engine and drivetrain is slowing down your coasting. If you would make it down to a stop point all under decel, then there is no difference to being in neutral.. but otherwise where you will be back on the gas before stopping, Neutral (or less aggressive downshifting, equivalently) may be better, allowing you to maintain a faster speed than in gear with the drag. Somewhat of an offset while in Neutral is you are using fuel to at least idle the engine. The MPG indicator pegs at 99.9 even whlie in Neutral and fuel is being used to idle the motor though.
Coasting down hills while in neutral isn't a good idea for a variety of safety and drive train stress related reasons.

Also you can just tap up on the paddles to pick a higher gear and hold it while descending. Once you get back on the gas, it will switch back into D within a couple seconds.
ocellaris is offline   Reply With Quote
Old 04-20-2012, 01:36 PM   #459
nubsub
Scooby Specialist
 
Member#: 313575
Join Date: Mar 2012
Location: SF Bay Area, CA
Vehicle:
2012 Impreza 2.0i HB

Default

Quote:
Originally Posted by ocellaris View Post
Coasting down hills while in neutral isn't a good idea for a variety of safety and drive train stress related reasons.

Also you can just tap up on the paddles to pick a higher gear and hold it while descending. Once you get back on the gas, it will switch back into D within a couple seconds.
neutral, i agree is a bad idea in general (that's one reason i always downshifted even approaching a light with my manual transmissions)

although i haven't tried it, but if i understand the owner's manual correctly, i think that if you actually put yourself into the "M" mode, you can actually hold the high gear. but if you are in the D mode, it does revert, ultimately to what the computer thinks is best.

in my limited use of the paddleshifters in D mode, i haven't figured out what this "revert" mode is because there are times i have found it reverts quickly back to D and other times, it let's me stay in my preset gear for quite a while.
nubsub is offline   Reply With Quote
Old 04-20-2012, 01:43 PM   #460
ocellaris
Scooby Specialist
 
Member#: 302559
Join Date: Nov 2011
Default

Quote:
Originally Posted by nubsub View Post
neutral, i agree is a bad idea in general (that's one reason i always downshifted even approaching a light with my manual transmissions)

although i haven't tried it, but if i understand the owner's manual correctly, i think that if you actually put yourself into the "M" mode, you can actually hold the high gear. but if you are in the D mode, it does revert, ultimately to what the computer thinks is best.

in my limited use of the paddleshifters in D mode, i haven't figured out what this "revert" mode is because there are times i have found it reverts quickly back to D and other times, it let's me stay in my preset gear for quite a while.
I think it switches back into D once the selected gear becomes "wrong" for acceleration, or when the selected gear would be spinning the engine under a certain RPM. When descending, I've never had it switch from my selected gear back into D until I hit the gas again (or when cruise control gets engaged again).

Anyway at this point, I am extremely interested in getting some details on that transmissions re-flash that buran288 received. If that is an actual thing and MPG goes up, I would drive to the dealer this weekend. Thought part of me think maybe they just reset the ECU and TCU.

Last edited by ocellaris; 04-20-2012 at 04:26 PM.
ocellaris is offline   Reply With Quote
Old 04-20-2012, 02:47 PM   #461
PAO56
Scooby Newbie
 
Member#: 304676
Join Date: Dec 2011
Chapter/Region: MAIC
Vehicle:
2012 Impreza Ltd 5DR
Deep Cherry Pearl

Default

Quote:
Originally Posted by nubsub View Post
thanks, pao. glad to see how the car evolves as the miles accumulate.

what is the "average speed" that your computer reports on a tank of this mixed driving?

...
As i recall.....the average is in the high 30's low 40's....I will check at my next fillup which should be tommorrow....
PAO56 is offline   Reply With Quote
Old 04-20-2012, 07:20 PM   #462
nubsub
Scooby Specialist
 
Member#: 313575
Join Date: Mar 2012
Location: SF Bay Area, CA
Vehicle:
2012 Impreza 2.0i HB

Default

2nd tank up today. 227.1 miles and 8.08 gallons. hand calcs gives 28.1 mpg, computer reads 29.4 mpg.

aside: interesting to note that at around 222, the 7th bar disappeared: (5 of 12 showing): this is something i'll have to do a mental calibration of in the future to see if i can figure out consistently what the bars translate to (at least on the below half side of things). i rarely run a tank down to the warning light, but it's nice to have a rough guide (i don't trust that "miles remaining" gauge at all yet. it seems all over the place so far. not sure if it's learning my driving or...)
nubsub is offline   Reply With Quote
Old 04-21-2012, 02:56 AM   #463
ST Eye
Scooby Specialist
 
Member#: 73068
Join Date: Oct 2004
Location: MD
Vehicle:
2008 STI Boost Wagon
2014 Honda Accord Hybrid

Default

I drove for 7 hours today in my Impreza. The first leg of the trip I calculated 37.2 MPG!! I was averaging ~72 MPH on 90% highway driving.
ST Eye is offline   Reply With Quote
Old 04-21-2012, 09:56 AM   #464
flyboy1100
Scooby Specialist
 
Member#: 314216
Join Date: Mar 2012
Location: ND
Vehicle:
2012 2.0i Sport 5MT
DGM

Default

the way i see it, it has to be better than the 22.8mpg I got yesterday when filling up my buick It used to get 30 on the highway at 75, not anymore.

so honestly if i can see 30mpg averages i will be really happy!
flyboy1100 is offline   Reply With Quote
Old 04-21-2012, 11:38 AM   #465
nubsub
Scooby Specialist
 
Member#: 313575
Join Date: Mar 2012
Location: SF Bay Area, CA
Vehicle:
2012 Impreza 2.0i HB

Default

Quote:
Originally Posted by ST Eye
I drove for 7 hours today in my Impreza. The first leg of the trip I calculated 37.2 MPG!! I was averaging ~72 MPH on 90% highway driving.
Great to hear!
nubsub is offline   Reply With Quote
Old 04-21-2012, 04:20 PM   #466
BIGD070572
Scooby Newbie
 
Member#: 312836
Join Date: Mar 2012
Chapter/Region: MWSOC
Location: Kansas City
Vehicle:
2012 sport prem. 5dr
Dark Gray Metallic

Default

DGM sport 5 spd
Tank 2 403.5 miles, ind. average mpg 31.2, 13.558 gal. Calculated 29.7. Mixed driving, 30/70 city/hwy including a/c use. I didnt document the avg mph, but I am consistently 65/70 mph hwy. I'm pleased so far.
BIGD070572 is offline   Reply With Quote
Old 04-21-2012, 04:21 PM   #467
Penguin44
Scooby Newbie
 
Member#: 315883
Join Date: Apr 2012
Chapter/Region: E. Canada
Vehicle:
2012 IMPREZA
Silver

Default

Just past first tank. Average speed 36kph. Average on computer 9l/100km.
Got 562km on the tank all city. The last bar had disappeared. There was about 3l left in the tank. Cvt base 5door. base model.
Penguin44 is offline   Reply With Quote
Old 04-21-2012, 06:57 PM   #468
2012 polish STI
Scooby Newbie
 
Member#: 317635
Join Date: Apr 2012
Chapter/Region: SCIC
Vehicle:
2012 WRX STI
Dark gray

Default

An air intake and exhaust will help u gain ur mpg
2012 polish STI is offline   Reply With Quote
Old 04-21-2012, 07:57 PM   #469
ST Eye
Scooby Specialist
 
Member#: 73068
Join Date: Oct 2004
Location: MD
Vehicle:
2008 STI Boost Wagon
2014 Honda Accord Hybrid

Default

Quote:
Originally Posted by 2012 polish STI View Post
An air intake and exhaust will help u gain ur mpg
And you know this how?
ST Eye is offline   Reply With Quote
Old 04-21-2012, 09:30 PM   #470
noahj
Scooby Newbie
 
Member#: 310829
Join Date: Feb 2012
Default OK so far

Just coming up on 1000 miles on the odo, and it looks like it's getting 29 mpg on an 80/20 mix of freeway and city driving. Good enough for me.

I think the mileage estimates on the center display are generally pretty wacky, which is what is making people nervous.
noahj is offline   Reply With Quote
Old 04-21-2012, 11:22 PM   #471
2012 polish STI
Scooby Newbie
 
Member#: 317635
Join Date: Apr 2012
Chapter/Region: SCIC
Vehicle:
2012 WRX STI
Dark gray

Default

Quote:
Originally Posted by ST Eye
And you know this how?
I had a intake and a exhaust and re mapped my ecu and saw better gas mileage
2012 polish STI is offline   Reply With Quote
Old 04-22-2012, 12:09 AM   #472
79letour
Scooby Specialist
 
Member#: 302570
Join Date: Nov 2011
Location: dear old dixie
Vehicle:
2013 XV
DGM!

Default

On what car? ^^^
79letour is offline   Reply With Quote
Old 04-22-2012, 12:19 AM   #473
2012 polish STI
Scooby Newbie
 
Member#: 317635
Join Date: Apr 2012
Chapter/Region: SCIC
Vehicle:
2012 WRX STI
Dark gray

Default

Quote:
Originally Posted by 79letour
On what car? ^^^
I'm a 2010 wrx
2012 polish STI is offline   Reply With Quote
Old 04-22-2012, 01:03 AM   #474
ans2k
Scooby Specialist
 
Member#: 315631
Join Date: Apr 2012
Location: Bryant, AR
Vehicle:
2012 Impreza Sport

Default

Quote:
Originally Posted by ST Eye View Post
And you know this how?
also saw this improvement in my s2000
ans2k is offline   Reply With Quote
Old 04-22-2012, 01:07 AM   #475
ST Eye
Scooby Specialist
 
Member#: 73068
Join Date: Oct 2004
Location: MD
Vehicle:
2008 STI Boost Wagon
2014 Honda Accord Hybrid

Default

Quote:
Originally Posted by 2012 polish STI View Post
I'm a 2010 wrx
I'm not trying to be a ball buster here, but I think it's rather premature for you to make a comment like that without having substantiating information backing it up. There are so many factors that can play into MPG. If you were truly getting better gas efficiency it is more likely due to the tune leaning out your maps and not the intake and/or exhaust.
ST Eye is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
New Impreza owner, low mpg? stuffedcabbage Newbies & FAQs 34 09-25-2012 10:10 PM
2012 Impreza Reviewed - Whytecliff to Seymour brendan_mac Vancouver Impreza Club Forum -- VIC 16 12-23-2011 01:12 PM
NJ Impreza owners - sighting Dan G General Forum Archive 76 10-06-2000 12:24 AM
Md or Va Impreza owners - I have an Impreza related question. Snoopy General Forum Archive 1 06-05-2000 08:08 AM


All times are GMT -4. The time now is 07:04 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.