Welcome to the North American Subaru Impreza Owners Club Thursday July 24, 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 Technical > Factory 2.0L Turbo Powertrain

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 09-09-2012, 09:15 PM   #1
Djimpreza02
Scooby Newbie
 
Member#: 328135
Join Date: Aug 2012
Location: CT
Vehicle:
2004 impreza WRX
Blue

Question 2.0L Turbo gas?

2004 Subaru Impreza WRX, 2.0L turbo, 5 speed.

I just realized that this car takes premium unleaded(91), I've been putting 87 in since I got it last week, I only re-filled 2-3 times, but is it going to hurt to put 87 in?


And should I start using 91 to be safe, I read the manual and it says 87 can be used if nothing else is available, but I have a feeling I should switch, and start using 91 on a regular basic?

Just wanted to check to see if I did damage putting 87 in, and whether or not it matters if I keep running it instead of 91?


Thanks guys,

Dave
* Registered users of the site do not see these ads.
Djimpreza02 is offline   Reply With Quote
Old 09-09-2012, 09:21 PM   #2
RoadKillDMD
Scooby Specialist
 
Member#: 284792
Join Date: Jun 2011
Chapter/Region: RMIC
Location: Vanilla Valley, CO
Vehicle:
2011 STI
Plasma Blue Pearl

Default

With lower octane gas, your engine is more prone to detonation when you are in boost. You can run as much 87 as you wish, but you shouldn't be using any throttle. I would start using 91 oct., especially if you like to get on it every once in a while.

Last edited by RoadKillDMD; 09-09-2012 at 10:52 PM.
RoadKillDMD is offline   Reply With Quote
Old 09-09-2012, 09:35 PM   #3
Djimpreza02
Scooby Newbie
 
Member#: 328135
Join Date: Aug 2012
Location: CT
Vehicle:
2004 impreza WRX
Blue

Default

Tuning? You mean using?

And if so, that is kinda what I though, but I think to play it safe, 91 will be going in from now on, cause I do like to hit it every once in a while.
Djimpreza02 is offline   Reply With Quote
Old 09-09-2012, 09:39 PM   #4
hoffmanEstates
Scooby Guru
 
Member#: 122043
Join Date: Aug 2006
Chapter/Region: MWSOC
Location: aurora
Vehicle:
04 wagonier
psm

Default

Have to pay to.play. as gas in.Chicago is 4.50-5$ a gal premium I still run premium. Never less we have 93
hoffmanEstates is offline   Reply With Quote
Old 09-09-2012, 09:42 PM   #5
Djimpreza02
Scooby Newbie
 
Member#: 328135
Join Date: Aug 2012
Location: CT
Vehicle:
2004 impreza WRX
Blue

Default

Ah, that's in another question, we don't have many places that use 91 around here either, so will 93 octane be good to run in it yearly?


Our pump options are usually: 87, 89, and 93.
Djimpreza02 is offline   Reply With Quote
Old 09-09-2012, 09:49 PM   #6
Pandasaurus_rex
Scooby Newbie
 
Member#: 157114
Join Date: Aug 2007
Chapter/Region: Tri-State
Location: Plattsburgh, NY
Vehicle:
2002 Impreza WRX
Aspen White & Carbonated

Default

The wrx has a special failsafe fueling map programmed into the ecu which it switches to if there's too much detonation. There are several layers of defense against knock in the stock ecu rom. The failsafe map runs alot richer than the base fueling map, so you'll consume alot more fuel and be down on power since in order for the ecu to switch to that map, it has to first retard the hell out of the ignition timing. This is all to protect the engine.
Pandasaurus_rex is offline   Reply With Quote
Old 09-09-2012, 09:52 PM   #7
subieguy87
Scooby Specialist
 
Member#: 153412
Join Date: Jul 2007
Chapter/Region: MWSOC
Location: Springfield,il
Vehicle:
1998 Impreza wrxRS
Black

Default

Quote:
Originally Posted by Djimpreza02
Ah, that's in another question, we don't have many places that use 91 around here either, so will 93 octane be good to run in it yearly?

Our pump options are usually: 87, 89, and 93.
10% ethanol blend? 91 is usually pure gas, 93 has 10% ethanol usually
subieguy87 is offline   Reply With Quote
Old 09-09-2012, 10:00 PM   #8
Djimpreza02
Scooby Newbie
 
Member#: 328135
Join Date: Aug 2012
Location: CT
Vehicle:
2004 impreza WRX
Blue

Default

Quote:
Originally Posted by Pandasaurus_rex View Post
The wrx has a special failsafe fueling map programmed into the ecu which it switches to if there's too much detonation. There are several layers of defense against knock in the stock ecu rom. The failsafe map runs alot richer than the base fueling map, so you'll consume alot more fuel and be down on power since in order for the ecu to switch to that map, it has to first retard the hell out of the ignition timing. This is all to protect the engine.
Yea on 87 we have only been getting 290 miles to a tank. But we also don't like to run it almost dry, I hear that's bad on a turbo engine.

Quote:
Originally Posted by subieguy87 View Post
10% ethanol blend? 91 is usually pure gas, 93 has 10% ethanol usually
And yes, I believe there is a 10% ethenol blend in all three of our options.
Djimpreza02 is offline   Reply With Quote
Old 09-09-2012, 10:08 PM   #9
subieguy87
Scooby Specialist
 
Member#: 153412
Join Date: Jul 2007
Chapter/Region: MWSOC
Location: Springfield,il
Vehicle:
1998 Impreza wrxRS
Black

Default

Quote:
Originally Posted by Djimpreza02

And yes, I believe there is a 10% ethenol blend in all three of our options.
some people prefer the non blended kind as it CAN clog lines & injectors, just like E85

It's owner preference.
subieguy87 is offline   Reply With Quote
Old 09-09-2012, 10:30 PM   #10
Djimpreza02
Scooby Newbie
 
Member#: 328135
Join Date: Aug 2012
Location: CT
Vehicle:
2004 impreza WRX
Blue

Default

Well they put 10% ethanol in all three grade's here in CT. So there is no avoiding it.

But so just so I got it right, I should run 93 with the un-avoidable 10% ethanol in it?
Djimpreza02 is offline   Reply With Quote
Old 09-09-2012, 10:50 PM   #11
lukeskywrx
Scooby Specialist
 
Member#: 59837
Join Date: Apr 2004
Chapter/Region: SWIC
Location: Arizona
Vehicle:
2004 Spec-C Type RA
What MAF? -Speed Density!

Default

Quote:
Originally Posted by Djimpreza02 View Post
Well they put 10% ethanol in all three grade's here in CT. So there is no avoiding it.

But so just so I got it right, I should run 93 with the un-avoidable 10% ethanol in it?
Just read the little sticker on the fuel door, "Premium Fuel Only". Pretty much all the gas in the US has some ethanol in it.
lukeskywrx is offline   Reply With Quote
Old 09-09-2012, 10:55 PM   #12
RoadKillDMD
Scooby Specialist
 
Member#: 284792
Join Date: Jun 2011
Chapter/Region: RMIC
Location: Vanilla Valley, CO
Vehicle:
2011 STI
Plasma Blue Pearl

Default

Quote:
Originally Posted by Djimpreza02
Tuning? You mean using?

And if so, that is kinda what I though, but I think to play it safe, 91 will be going in from now on, cause I do like to hit it every once in a while.
Yes I do ! Stupid phone auto correct
RoadKillDMD is offline   Reply With Quote
Old 09-09-2012, 11:03 PM   #13
Djimpreza02
Scooby Newbie
 
Member#: 328135
Join Date: Aug 2012
Location: CT
Vehicle:
2004 impreza WRX
Blue

Default

Okay, thanks guys, I'll start running 93.

Dave
Djimpreza02 is offline   Reply With Quote
Old 09-09-2012, 11:55 PM   #14
subieguy87
Scooby Specialist
 
Member#: 153412
Join Date: Jul 2007
Chapter/Region: MWSOC
Location: Springfield,il
Vehicle:
1998 Impreza wrxRS
Black

Default

Quote:
Originally Posted by Djimpreza02
Well they put 10% ethanol in all three grade's here in CT. So there is no avoiding it.

But so just so I got it right, I should run 93 with the un-avoidable 10% ethanol in it?
But you will find some gas stations have 93 premium & some have 91. Don't worry about regular or super/plus(w/e they want to call it) anymore
subieguy87 is offline   Reply With Quote
Old 09-19-2012, 07:46 PM   #15
Djimpreza02
Scooby Newbie
 
Member#: 328135
Join Date: Aug 2012
Location: CT
Vehicle:
2004 impreza WRX
Blue

Default

Update: Okay well we are on our second tank of 93, and I think the gas mileage is worse?


12.25 gallons only got me 250 miles.

I just filled up again, and I'm already at almost half a tank with only 135 miles.
Djimpreza02 is offline   Reply With Quote
Old 09-19-2012, 08:22 PM   #16
Concillian
Scooby Guru
 
Member#: 4414
Join Date: Feb 2001
Location: Dublin, CA
Vehicle:
2002 WRX Sedan
Midnight Black

Default

gas mileage differences are usually due to driving differences during the tank. If you get on it, a turbo car drinks gas like a homeless guy drinks fortified wine.

My MPG on 91 varied from ~18 to 29 depending on how I drove. 29 being speed limit highway driving and 18 being lots of city driving and/or WOT tuning pulls. I would usually get between 22 and 25 on normal driving.

It's pretty common to have a heavier right foot when you first get a performance boost, could you have been a little heavier footed with the 91 since the performance picked up a little?

Last edited by Concillian; 09-19-2012 at 09:14 PM.
Concillian is offline   Reply With Quote
Old 09-19-2012, 08:35 PM   #17
subieguy87
Scooby Specialist
 
Member#: 153412
Join Date: Jul 2007
Chapter/Region: MWSOC
Location: Springfield,il
Vehicle:
1998 Impreza wrxRS
Black

Default

Quote:
Originally Posted by Concillian
It's pretty common to have a heavier left foot when you first get a performance boost
Left foot?
subieguy87 is offline   Reply With Quote
Old 09-19-2012, 08:43 PM   #18
xXsaabaruXx
Scooby Newbie
 
Member#: 232125
Join Date: Dec 2009
Chapter/Region: NWIC
Location: The 503 Milwaukie, Oregon
Vehicle:
2005 92x Aero
black

Default

haha i was going to say the same thing^^^^^
xXsaabaruXx is offline   Reply With Quote
Old 09-19-2012, 08:45 PM   #19
Djimpreza02
Scooby Newbie
 
Member#: 328135
Join Date: Aug 2012
Location: CT
Vehicle:
2004 impreza WRX
Blue

Default

That is what I said to my GF, and she said she has been shifting between 2000 and 2500 RPM?
Djimpreza02 is offline   Reply With Quote
Old 09-19-2012, 09:14 PM   #20
Concillian
Scooby Guru
 
Member#: 4414
Join Date: Feb 2001
Location: Dublin, CA
Vehicle:
2002 WRX Sedan
Midnight Black

Default

lol, of course I meant right foot.

Everyone makes mistakes. Though if you rest your foot on the brake, a heavy left foot can cause MPG issues too
Concillian is offline   Reply With Quote
Old 09-19-2012, 09:18 PM   #21
Concillian
Scooby Guru
 
Member#: 4414
Join Date: Feb 2001
Location: Dublin, CA
Vehicle:
2002 WRX Sedan
Midnight Black

Default

Quote:
Originally Posted by Djimpreza02 View Post
That is what I said to my GF, and she said she has been shifting between 2000 and 2500 RPM?
Sounds painfully slow on a 2.0L.

The bottom line is that octane shouldn't really affect MPG, as the amount of fuel the ECU gives isn't changed by the octane. If octane can't support the performance, the ECU adjusts ignition timing, not fueling (unless the knocking is REALLY bad and it's sent into limp mode, which uses a super rich backup fuel map.)
Concillian is offline   Reply With Quote
Old 09-19-2012, 09:25 PM   #22
Synx
Scooby Specialist
 
Member#: 43712
Join Date: Sep 2003
Chapter/Region: TXIC
Location: Shreveport, LA
Vehicle:
60's B-52H
03 WRX WRB

Default

I have never heard of 10% ethanol clogging a fuel filter. I have run 10% ethanol in my 02 WRX since I've owned it. You need to understand how octane ratings work and what octane means.

First off octane is a measure of anti detonation properties of fuel, otherwise, more resistance to compression before detonation. So looking at the EJ20 or any Turbo motor or high performance motor, we have a rather low compression ratio but that is greatly increased by forced induction. So with all things equal our motors have a relatively high cylinder pressure. Because of this we need a fuel that is highly resistant to detonation.

What we see in the US and Canada (not sure about elsewhere) is a Research (Octane (RON) + Motor Octane (MON))/2. So an adverage of RON and MON. The difference between RON and MON is that RON is measured at 600rpm and MON is measured at 900rpm.

Practically, if you are running E85 (85% Ethanol) or 93 with 10% ethanol, the US octane ratings include both RON and MON to come up with a detonation resistance fuel rating. In the case of ethanol there is some documentation of fuel filter clogging in our cars but only when switching to E85, so large percentages of ethanol, after running normal fuel for longer periods of time.

There are some concerns when running large quants of ethanol such as injector duty cycle and fueling equipment construction material, but I have never heard of issues with 10% ethanol in modern cars. The fact that it is certified in the US at gas stations should be enough for your peace of mind.

In short, run low octane rated fuel all you want, but dont expect any performance out of your vehicle and DO NOT ABUSE IT, our ECU (engine computer) is smart enough to remove timing when it see's detonation, but if you abuse it at higher RPM will turn a blind eye and gladly let you detonate the motor to extinction.
Synx is offline   Reply With Quote
Old 09-19-2012, 10:38 PM   #23
Djimpreza02
Scooby Newbie
 
Member#: 328135
Join Date: Aug 2012
Location: CT
Vehicle:
2004 impreza WRX
Blue

Default

So this gas millage is normal? I mean I might expect to gain a few more MPG as the Computer gets more used to the 93, but I can't see it busting 300miles, even if I used 14 gallons?
Djimpreza02 is offline   Reply With Quote
Old 09-20-2012, 01:37 AM   #24
Uncle Scotty
Scooby Guru
 
Member#: 16200
Join Date: Mar 2002
Vehicle:
OK Houston
we have an Uncle

Default

Quote:
Originally Posted by Djimpreza02 View Post
So this gas millage is normal? I mean I might expect to gain a few more MPG as the Computer gets more used to the 93, but I can't see it busting 300miles, even if I used 14 gallons?
replace the front o2 sensor...clean/replace the maf...replace the air filter.....hard reset on the ecu and see what happens
Uncle Scotty is offline   Reply With Quote
Old 09-20-2012, 08:23 AM   #25
quazimoto
Scooby Guru
 
Member#: 70395
Join Date: Sep 2004
Chapter/Region: MAIC
Location: Da-boonies,Va
Default

Quote:
Originally Posted by Uncle Scotty View Post
replace the front o2 sensor...clean/replace the maf...replace the air filter.....hard reset on the ecu and see what happens
This. Also there are so many other variables that are involved with gas mileage. Ambient temps,tire pressure,right foot usage............
quazimoto is online now   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


All times are GMT -4. The time now is 07:46 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.