Welcome to the North American Subaru Impreza Owners Club Sunday April 20, 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 General > Newbies & FAQs

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 05-28-2009, 07:21 PM   #1
ericpratum
Scooby Newbie
 
Member#: 212471
Join Date: May 2009
Chapter/Region: NWIC
Location: Mercer Island
Vehicle:
2008 Impreza 2.5i
Black Obsidian Pearl

Default New 08 2.5i - Advice on Better Gas Mileage Mods

I just got this, and obviously don't want to void my warranty, but where can I start to get better gas mileage (other than driving less aggressively, which I've already taken care of)? And, yes, I know that most people want their subies to go fast, but I don't much care about the speed or power... If I did, I would've gone with the WRX.

One friend suggested getting my cam ground for economy. Others mentioned a grill block, rear wheel skirts, front lip, side skirts, beatrush-style under panel/tray, and a perrin air filter. I have zero experience with this sort of stuff and very few tools, but I have several friends with welding shops, tools, carbon fiber set ups, etc, so I imagine I can have them help me with some of the work and can find shops to do/fabricate the rest.

So, for a completely stock 08 2.5i, what's the most bang for my buck that won't void my warranty? What works? What doesn't? (And, no, I don't much care if if makes the car look "ugly") Any advice would be much appreciated.
* Registered users of the site do not see these ads.
ericpratum is offline   Reply With Quote
Old 05-28-2009, 07:31 PM   #2
testify
*** Banned ***
 
Member#: 196517
Join Date: Dec 2008
Chapter/Region: NESIC
Location: Mcnoobsville
Vehicle:
2007 n00b rocket
urban grey metallic

Default

In my opinion, the simplest thing is to just keep your right foot out of the throttle. Everything you've mentioned(aside from the aerodynamics) has fairly large costs attached to it and will void your warranty and/or be grounds for denial of warranty work. You have to look at it as how quickly the cost of the modification will be offset by the savings($500 for an extra 2-3mpg isn't worth it in my opinion). And thats if any of the forementioned things even work.
testify is offline   Reply With Quote
Old 05-28-2009, 08:13 PM   #3
fiveoh88
Scooby Specialist
 
Member#: 125600
Join Date: Sep 2006
Chapter/Region: South East
Location: the OLD 9-0-4
Vehicle:
2005 STi perrin stg2
World Rally Blue

Default

you should be able to crack 30 mpg HWY easy just by using some hypermiling techniques...i pull 27 mpg from my car with a mix of mostly HWY, some CTY just by driving it easy and staying out of boost. i would think with the 2.5i you should be able to get pretty good MPGs just by how you drive it and a different car would be a better choice if you really need crazy gas mileage >3X MPG.
fiveoh88 is offline   Reply With Quote
Old 05-28-2009, 08:18 PM   #4
RexTexWagon
Scooby Specialist
 
Member#: 150987
Join Date: Jun 2007
Chapter/Region: TXIC
Location: Austin, Tx
Vehicle:
2013 Ford Focus ST3
White

Default

First off, understand that making modifications to your car will not void your warranty...

http://forums.nasioc.com/forums/showthread.php?t=803106

Please read that.

2nd off, everything you listed is absurdly expensive and for the little in return you will gain, you might as well have bought a yaris.


Do like fiveoh mentioned and just dont be lead footed with the car.
RexTexWagon is offline   Reply With Quote
Old 05-28-2009, 08:23 PM   #5
Howl
Scooby Specialist
 
Member#: 57830
Join Date: Mar 2004
Location: Ontario CA
Vehicle:
1999 OBS

Default

Put a small block of wood under the gas pedal so it only goes halfway down.
Howl is offline   Reply With Quote
Old 05-28-2009, 08:29 PM   #6
marcmtb35
Scooby Specialist
 
Member#: 171151
Join Date: Feb 2008
Chapter/Region: MAIC
Location: Gold's Gym Glen Burnie
Vehicle:
2013 C'dale Scalpel
White + dirt

Default

Skipshift 1 to 4 ala Corvette.
marcmtb35 is offline   Reply With Quote
Old 05-28-2009, 08:37 PM   #7
testify
*** Banned ***
 
Member#: 196517
Join Date: Dec 2008
Chapter/Region: NESIC
Location: Mcnoobsville
Vehicle:
2007 n00b rocket
urban grey metallic

Default

Quote:
Originally Posted by testify View Post
and/or be grounds for denial of warranty work.
Quote:
Originally Posted by RexTexWagon View Post
First off, understand that making modifications to your car will not void your warranty...

http://forums.nasioc.com/forums/showthread.php?t=803106

Please read that.
I take it you've never been through a warranty battle with a dealer who feared an audit from SOA.
testify is offline   Reply With Quote
Old 05-28-2009, 08:50 PM   #8
Speedette
Scooby Newbie
 
Member#: 104272
Join Date: Jan 2006
Chapter/Region: MAIC
Location: Centreville, VA
Vehicle:
2002 WRX
ClubWRX Ambassador

Default

Quote:
Originally Posted by testify View Post
I take it you've never been through a warranty battle with a dealer who feared an audit from SOA.
It's clear that he hasn't.

Why did you buy the car in the 1st place if you knew you weren't gonna get the gas mileage you wanted?
Speedette is offline   Reply With Quote
Old 05-28-2009, 08:52 PM   #9
RexTexWagon
Scooby Specialist
 
Member#: 150987
Join Date: Jun 2007
Chapter/Region: TXIC
Location: Austin, Tx
Vehicle:
2013 Ford Focus ST3
White

Default

Quote:
Originally Posted by testify View Post
I take it you've never been through a warranty battle with a dealer who feared an audit from SOA.

So when you broke your transmission from abusing it and you wanted your window motor repaired because it stopped functioning, they denied you? Those bastards!



They can deny warranty work, but nothing will ever void your warranty unless it falls around those guidelines as posted in the link. Sure I wouldn't expect them to cover my transmission if I took my car to the track every day on a 35r setup doing 6k clutch bombs, but if my headlights went out and I was still with in my 3/36k, they had better fix that.
RexTexWagon is offline   Reply With Quote
Old 05-28-2009, 09:13 PM   #10
testify
*** Banned ***
 
Member#: 196517
Join Date: Dec 2008
Chapter/Region: NESIC
Location: Mcnoobsville
Vehicle:
2007 n00b rocket
urban grey metallic

Default

Quote:
Originally Posted by RexTexWagon View Post
So when you broke your transmission from abusing it and you wanted your window motor repaired because it stopped functioning, they denied you? Those bastards!



They can deny warranty work, but nothing will ever void your warranty unless it falls around those guidelines as posted in the link. Sure I wouldn't expect them to cover my transmission if I took my car to the track every day on a 35r setup doing 6k clutch bombs, but if my headlights went out and I was still with in my 3/36k, they had better fix that.
Mine launched a rod at 25k miles, I had all reciepts for scheduled maintainance and oil changes. The first dealer wouldn't even touch the car b/c it "had been raced" because of the modifications(swaybars and obvious "autox tires"[falken azenis{I took this issue as far as I could up the SOA chain}]). I'm not saying that this is an automatic response if you bring your car to the dealer for warranty work. But whether you want to belive it or not, you do concede some 'say' as to whether they will perform warranty work when you modify your car.

Hello...anybody home? OP is talking about cam regrinds/header modification, etc..... Thats definately going to be grounds for denial of warranty work if his car launches a rod.

Last edited by testify; 05-29-2009 at 09:20 AM.
testify is offline   Reply With Quote
Old 05-28-2009, 09:15 PM   #11
againstdan
Scooby Specialist
 
Member#: 96093
Join Date: Sep 2005
Chapter/Region: SCIC
Location: riverside ca
Vehicle:
2002 impreza wrx
platinum silver

Default

Quote:
Originally Posted by Howl View Post
Put a small block of wood under the gas pedal so it only goes halfway down.
^^^awesome
againstdan is offline   Reply With Quote
Old 05-28-2009, 09:19 PM   #12
cmiovino
Scooby Guru
 
Member#: 134005
Join Date: Dec 2006
Chapter/Region: MAIC
Location: Pittsburgh, PA
Vehicle:
2004 WRX Premium
PSM

Default

Skip all that aerodynamic stuff. Mainly, continue to work on the hypermiling techniques. If you do a lot of highway driving, try keeping it about 55MPH max if you can. Any higher and wind resistance kicks in as a bigger factor. Remember to coast to stops too.

Most mods aren't going to increase gas mileage. Things like intakes, exhausts, probably won't net you much if anything. Just remember, you bought a Subaru - a great commuter car (2.5i trim) for all types of weather, but not a great gas saver. That AWD takes up a lot.

I got 24-25 MPG in my '95 2.2 and I get 25 MPG in my '98 2.2
That's all highway, 4EAT, very light throttle.
cmiovino is offline   Reply With Quote
Old 05-28-2009, 09:20 PM   #13
RexTexWagon
Scooby Specialist
 
Member#: 150987
Join Date: Jun 2007
Chapter/Region: TXIC
Location: Austin, Tx
Vehicle:
2013 Ford Focus ST3
White

Default

Quote:
Originally Posted by testify View Post
Mine launched a rod at 25k miles, I had all reciepts for scheduled maintainance and oil changes. The first dealer wouldn't even touch the car b/c it "had been raced" because of the modifications(swaybars and obvious "autox tires"[falken azenis{I took this issue as far as I could up the SOA chain}]). I'm not saying that this is an automatic response if you bring your car to the dealer for warranty work. But whether you want to belive it or not, you do concede some 'say' as to whether they will perform warranty work when you modify your car.

Hello...anybody home? OP is talking about cam regrinds/header modification, etc..... Thats definately going to be grounds for denial of warranty work if his car launches a rod.

And so your saying because you "launched a rod", you hadn't taken it to autox days, or driven it hard on the roads in high revs.

Anywho, this is about OP, not you. Yes, he will get warranty work denied for motor related issues by wasting alot of money custom grinding cams, but it will not void his warranty. Lets get the lingo strait here bub.
RexTexWagon is offline   Reply With Quote
Old 05-28-2009, 09:27 PM   #14
testify
*** Banned ***
 
Member#: 196517
Join Date: Dec 2008
Chapter/Region: NESIC
Location: Mcnoobsville
Vehicle:
2007 n00b rocket
urban grey metallic

Default

Quote:
Originally Posted by testify View Post
will void your warranty and/or be grounds for denial of warranty work.
Quote:
Originally Posted by RexTexWagon View Post
First off, understand that making modifications to your car will not void your warranty....
Quote:
Originally Posted by RexTexWagon View Post
Yes, he will get warranty work denied for motor related issues by wasting alot of money custom grinding cams, but it will not void his warranty. Lets get the lingo strait here bub.

READING COMPREHENSION!

lets work on it a wee bit, kthnxbai

and aside from anything in that thread about warranty denials. You should read the SOA warranty agreement. Its very informative.
testify is offline   Reply With Quote
Old 05-28-2009, 09:30 PM   #15
RexTexWagon
Scooby Specialist
 
Member#: 150987
Join Date: Jun 2007
Chapter/Region: TXIC
Location: Austin, Tx
Vehicle:
2013 Ford Focus ST3
White

Default

Quote:
Originally Posted by testify View Post
READING COMPREHENSION!

lets work on it a wee bit, kthnxbai

and aside from anything in that thread about warranty denials. You should read the SOA warranty agreement. Its very informative.
You should probably use some of that your self and realize that post you were referring me to, I was talking to the OP, as I could care less about your cry story.
RexTexWagon is offline   Reply With Quote
Old 05-28-2009, 09:31 PM   #16
ericpratum
Scooby Newbie
 
Member#: 212471
Join Date: May 2009
Chapter/Region: NWIC
Location: Mercer Island
Vehicle:
2008 Impreza 2.5i
Black Obsidian Pearl

Default

Quote:
Originally Posted by Speedette View Post
It's clear that he hasn't.

Why did you buy the car in the 1st place if you knew you weren't gonna get the gas mileage you wanted?
When did I say that I wasn't getting the gas mileage I want? I'm just looking to improve it anywhere that I can. Is that a bad thing? Thanks for the snarky, not useful comment.
ericpratum is offline   Reply With Quote
Old 05-28-2009, 09:34 PM   #17
testify
*** Banned ***
 
Member#: 196517
Join Date: Dec 2008
Chapter/Region: NESIC
Location: Mcnoobsville
Vehicle:
2007 n00b rocket
urban grey metallic

Default

*leans back in rocking chair*

Had a 1984 civic hatch. Weighed 1800lbs and had a 63HP 1.3L in it, with 4 on the floor. Got 50+mpg in dat sunnnofffaagunnn! Those were the days!
testify is offline   Reply With Quote
Old 05-28-2009, 09:36 PM   #18
ericpratum
Scooby Newbie
 
Member#: 212471
Join Date: May 2009
Chapter/Region: NWIC
Location: Mercer Island
Vehicle:
2008 Impreza 2.5i
Black Obsidian Pearl

Default

Wow. My first new thread and already people are fighting over the stupidest issues.

Seriously, the point is that I would like get better gas mileage if possible, but I don't want to waste money or do anything unnecessary for that goal. I bought the 2.5i because I wanted to stick with Subaru... drove a 91 Legacy from new 'til just last month. I like the cars, and I like my 2.5i. If I can improve my gas mileage, great. If not, no worries. I'm still happy with the car I have.
ericpratum is offline   Reply With Quote
Old 05-28-2009, 09:37 PM   #19
RexTexWagon
Scooby Specialist
 
Member#: 150987
Join Date: Jun 2007
Chapter/Region: TXIC
Location: Austin, Tx
Vehicle:
2013 Ford Focus ST3
White

Default

Quote:
Originally Posted by ericpratum View Post
Wow. My first new thread and already people are fighting over the stupidest issues.

Seriously, the point is that I would like get better gas mileage if possible, but I don't want to waste money or do anything unnecessary for that goal. I bought the 2.5i because I wanted to stick with Subaru... drove a 91 Legacy from new 'til just last month. I like the cars, and I like my 2.5i. If I can improve my gas mileage, great. If not, no worries. I'm still happy with the car I have.
Then do what was mentioned a few posts in. Just go easy on the throttle.

/thread
RexTexWagon is offline   Reply With Quote
Old 05-28-2009, 09:38 PM   #20
ericpratum
Scooby Newbie
 
Member#: 212471
Join Date: May 2009
Chapter/Region: NWIC
Location: Mercer Island
Vehicle:
2008 Impreza 2.5i
Black Obsidian Pearl

Default

Quote:
Originally Posted by testify View Post
*leans back in rocking chair*

Had a 1984 civic hatch. Weighed 1800lbs and had a 63HP 1.3L in it, with 4 on the floor. Got 50+mpg in dat sunnnofffaagunnn! Those were the days!
Wow. Nice. Getting 30something highway on average with the 2.5i and was getting just over 25 highway in my 91 Legacy. Who knows... maybe I'll find something beyond hypermiling.
ericpratum is offline   Reply With Quote
Old 05-28-2009, 09:41 PM   #21
suub07
Scooby Newbie
 
Member#: 163702
Join Date: Nov 2007
Chapter/Region: TXIC
Location: Odessa TX
Vehicle:
2007 impreza 2.5
UGM

Default

geo metro LSi.

60 MPG

comes with a removable soft top. Chicks dig convertibles.



oooooor, I just use my cruise control and can pull down 32 mpg on long trips.
suub07 is offline   Reply With Quote
Old 05-28-2009, 09:46 PM   #22
ericpratum
Scooby Newbie
 
Member#: 212471
Join Date: May 2009
Chapter/Region: NWIC
Location: Mercer Island
Vehicle:
2008 Impreza 2.5i
Black Obsidian Pearl

Default

Quote:
Originally Posted by suub07 View Post
geo metro LSi.

60 MPG

comes with a removable soft top. Chicks dig convertibles.



oooooor, I just use my cruise control and can pull down 32 mpg on long trips.
My buddy said a local shop ground the cam in their Metro and got it to go from 40mpg to 60+mpg, but he told me that sort of work is "crazy." Considering that I know little about engine mods, I mainly assumed that he meant you don't get your money's worth due to the expense.
ericpratum is offline   Reply With Quote
Old 05-28-2009, 09:53 PM   #23
testify
*** Banned ***
 
Member#: 196517
Join Date: Dec 2008
Chapter/Region: NESIC
Location: Mcnoobsville
Vehicle:
2007 n00b rocket
urban grey metallic

Default

Quote:
Originally Posted by ericpratum View Post
My buddy said a local shop ground the cam in their Metro and got it to go from 40mpg to 60+mpg, but he told me that sort of work is "crazy." Considering that I know little about engine mods, I mainly assumed that he meant you don't get your money's worth due to the expense.

Look at the prius, it takes like 60,000 miles to make your money back on gas mileage to offset the extra cost of, well, buying the prius. If a prius wasn't hybrid it would cost thousands less. And hybrid or not, my little hatch would still beat it in a MPG war.
testify is offline   Reply With Quote
Old 05-28-2009, 09:59 PM   #24
seattle944t
Scooby Specialist
 
Member#: 18308
Join Date: May 2002
Chapter/Region: NWIC
Location: Seattle, WA
Vehicle:
2005 WRX STi
Silver

Default

Run your tires at 40PSI.
seattle944t is offline   Reply With Quote
Old 05-28-2009, 10:10 PM   #25
Rwolf
Scooby Newbie
 
Member#: 210768
Join Date: May 2009
Location: Calgary, AB
Vehicle:
2009 Impreza Hatch
White

Default

I am getting about 7.6 L/100km - 31 mpg? city, avoiding busy traffic, driving primarily 4th, then 5th, or 3rd gear when at speed. Then again I'm still waiting for the engine to break in so that may change.
Rwolf 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
better gas mileage on wrxs?!?! filipin0y General Community 36 07-26-2009 11:34 AM
Brand New Catback on my 08 2.5i tylere Normally Aspirated Powertrain 11 09-23-2008 11:44 AM
Mods = Better Gas Mileage? VuONG Newbies & FAQs 32 10-22-2005 11:30 PM
Better gas mileage with Unichip stage 2? TurismoLou Factory 2.0L Turbo Powertrain 4 05-03-2002 09:06 AM


All times are GMT -4. The time now is 08:29 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.