Welcome to the North American Subaru Impreza Owners Club Monday October 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 Technical > Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo)

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 04-15-2013, 02:50 PM   #1
K2e2vin
Scooby Newbie
 
Member#: 308481
Join Date: Jan 2012
Chapter/Region: South East
Location: Raleigh, NC
Vehicle:
2005 Legacy GT

Default "hot air" intake?

Not sure if this is the right place but I've noticed that when it's cold, my fuel economy takes a, IMO, significant hit. With all-seasons, I was getting roughly 19-20mpg avg when it was cold(around 30F) and as the weather warmed up to currently around 75F, I'm up to 24.3mpg using the stock MPG gauge. Even when I still had my snow tires on, I noticed I was getting better MPG as the weather warmed up(I managed to get about 30mpg/hwy with the snow tires in about 75F weather, but with hypermilling).

First off, good idea, or bad idea? What would the max temperature threshold be before I start running into issues?

Anyways, I've thought about modifying the intake by removing the intake piece that goes between the hood and radiator support so it'll be pulling in hot air after the radiator(I've seen this on some stock cars); but then it'll be cooled by the intercooler anyways. Or, would it be better to just block off the intercooler somehow(with maybe some sort of shutter that can open/close)? I don't plan on doing it any time soon, but want to plan this out before winter rolls around and give myself plenty of time to implement it if possible.

This is a version 9 EJ207 swapped LGT btw.
* Registered users of the site do not see these ads.
K2e2vin is offline   Reply With Quote
Old 04-15-2013, 02:58 PM   #2
ogboot
Scooby Specialist
 
Member#: 170906
Join Date: Feb 2008
Chapter/Region: South East
Vehicle:
2002 WRX
psm

Default

Are you considering making the engine pull in hotter air in an attempt to get better gas mileage?

No.
ogboot is offline   Reply With Quote
Old 04-15-2013, 03:18 PM   #3
animalcrackers
Scooby Newbie
 
Member#: 271364
Join Date: Jan 2011
Chapter/Region: SWIC
Location: Tucson
Vehicle:
2002 and 2006 WRX
AW - OPB

Default

definite no.
animalcrackers is offline   Reply With Quote
Old 04-15-2013, 03:38 PM   #4
jayman4312
Scooby Specialist
 
Member#: 228784
Join Date: Nov 2009
Chapter/Region: MWSOC
Location: Chicago, IL
Vehicle:
2004 wrx
black, stage 2+

Default

You bought the wrong car if you really want to focus on MPG...you would ave more $$ by getting an 87 octane tune.
jayman4312 is offline   Reply With Quote
Old 04-15-2013, 03:42 PM   #5
jthatch12
Scooby Specialist
 
Member#: 321715
Join Date: May 2012
Chapter/Region: Tri-State
Location: Philly/SJ
Vehicle:
03 Big 16G WRX
PSM

Default

You do realize that cold air is more dense then hot air.....
jthatch12 is offline   Reply With Quote
Old 04-15-2013, 03:49 PM   #6
ogboot
Scooby Specialist
 
Member#: 170906
Join Date: Feb 2008
Chapter/Region: South East
Vehicle:
2002 WRX
psm

Default

Quote:
Originally Posted by jayman4312 View Post
You bought the wrong car if you really want to focus on MPG...you would ave more $$ by getting an 87 octane tune.
V9 ej207 swap at that, and claiming 30mpg. I don't think you're going to do much better with a JDM swap....
ogboot is offline   Reply With Quote
Old 04-15-2013, 04:06 PM   #7
Shortpersonbk
Scooby Specialist
 
Member#: 319017
Join Date: May 2012
Chapter/Region: MWSOC
Location: Michigan
Vehicle:
12 slow sti 6266 e
10.48 @134

Default

I want to punch my self for being of the same species as the OP at the thought of attempting to pull hot air into your engine
Shortpersonbk is online now   Reply With Quote
Old 04-15-2013, 04:58 PM   #8
quazimoto
Scooby Guru
 
Member#: 70395
Join Date: Sep 2004
Chapter/Region: MAIC
Location: Da-boonies,Va
Default

Step 1: Sell car
Step 2 : Buy Prius or Bike
quazimoto is offline   Reply With Quote
Old 04-15-2013, 05:04 PM   #9
K2e2vin
Scooby Newbie
 
Member#: 308481
Join Date: Jan 2012
Chapter/Region: South East
Location: Raleigh, NC
Vehicle:
2005 Legacy GT

Default

Quote:
Originally Posted by jthatch12 View Post
You do realize that cold air is more dense then hot air.....
I do realize that, and that's good for making power...but doesn't necessarily help with fuel economy.

I use my car for long trips to the mountains so increasing the range, not necessarily the cost savings, is desirable for me. I'm not going for the highest MPG out there, but rather trying to get it to run the same in the winter as it does in the summer.

30MPG was hypermilling; almost no stops and a steady 55mph with lots of traffic(drafting). My brother, driving my car in warm weather at higher speeds, was getting 25-26mpg...again that was warm weather and drafting. Cold weather rolls along, and it drops pretty significantly(on the same route my brother was getting 25-26mpg, I was getting just under 20mpg about two months prior).

Last edited by K2e2vin; 04-15-2013 at 05:11 PM.
K2e2vin is offline   Reply With Quote
Old 04-15-2013, 05:08 PM   #10
K2e2vin
Scooby Newbie
 
Member#: 308481
Join Date: Jan 2012
Chapter/Region: South East
Location: Raleigh, NC
Vehicle:
2005 Legacy GT

Default

Quote:
Originally Posted by Shortpersonbk View Post
I want to punch my self for being of the same species as the OP at the thought of attempting to pull hot air into your engine
As stated before, this is not uncommon at all. Warm air helps with flame propagation, combustion, and in some cases reduces pumping loss(higher throttle angle for the same air mass; some cars simply use a small TB to achieve this).

Of course, downside is you'd have to pull timing and you're more prone ping; which is why I'm interested in the threshold if anybody has drivin their car in hot weather.
K2e2vin is offline   Reply With Quote
Old 04-15-2013, 05:41 PM   #11
ogboot
Scooby Specialist
 
Member#: 170906
Join Date: Feb 2008
Chapter/Region: South East
Vehicle:
2002 WRX
psm

Default

Poor ej207

You could log some parameters to determine it yourself, it's not going to be static because of all kinds of environmental factors. I'm not going to provide anymore input though, as it's a travesty to that beautiful motor.
ogboot is offline   Reply With Quote
Old 04-15-2013, 05:53 PM   #12
K2e2vin
Scooby Newbie
 
Member#: 308481
Join Date: Jan 2012
Chapter/Region: South East
Location: Raleigh, NC
Vehicle:
2005 Legacy GT

Default

Don't worry, it gets put through its paces on some weekends. Also, I'm not looking into permanent mods. Thanks for the input! I just need a way to control intake temp to make an accurate comparison
K2e2vin is offline   Reply With Quote
Old 04-15-2013, 06:35 PM   #13
jthatch12
Scooby Specialist
 
Member#: 321715
Join Date: May 2012
Chapter/Region: Tri-State
Location: Philly/SJ
Vehicle:
03 Big 16G WRX
PSM

Default

Quote:
Originally Posted by K2e2vin View Post

I do realize that, and that's good for making power...but doesn't necessarily help with fuel economy.

I use my car for long trips to the mountains so increasing the range, not necessarily the cost savings, is desirable for me. I'm not going for the highest MPG out there, but rather trying to get it to run the same in the winter as it does in the summer.

30MPG was hypermilling; almost no stops and a steady 55mph with lots of traffic(drafting). My brother, driving my car in warm weather at higher speeds, was getting 25-26mpg...again that was warm weather and drafting. Cold weather rolls along, and it drops pretty significantly(on the same route my brother was getting 25-26mpg, I was getting just under 20mpg about two months prior).
You also do realize that gas in the winter has more ethanol which burns quicker than gas.... Therefore worse gas milage. OP, please do not follow through on this. There is no correlation between your car getting better mileage and hot intake charge
jthatch12 is offline   Reply With Quote
Old 04-15-2013, 08:31 PM   #14
HinshawWRX
Medium Frank
Moderator
 
Member#: 140114
Join Date: Feb 2007
Chapter/Region: MAIC
Location: Common Sense, VA
Vehicle:
2014 Porsche
GT3 (Currently on Fire)

Default

Your worse mpg's have nothing to do with wearing tires, winter gas blend, or a number of other environmental factors.
HinshawWRX is offline   Reply With Quote
Old 04-15-2013, 09:32 PM   #15
Uncle Scotty
Scooby Guru
 
Member#: 16200
Join Date: Mar 2002
Vehicle:
OK Houston
we have an Uncle

Default

Quote:
Originally Posted by K2e2vin View Post
As stated before, this is not uncommon at all. Warm air helps with flame propagation, combustion, and in some cases reduces pumping loss(higher throttle angle for the same air mass; some cars simply use a small TB to achieve this).

Of course, downside is you'd have to pull timing and you're more prone ping; which is why I'm interested in the threshold if anybody has drivin their car in hot weather.


go back to school and see where you are way outta yer mind here

we are talking about supercharged engines here.... and an optimized tune is what you want

not ****ing hot air intake

learn to tune and tune it yourself and you will see better mpg

and not blow it up with hot air intake
Uncle Scotty is offline   Reply With Quote
Old 04-15-2013, 11:08 PM   #16
IA Performance
NASIOC Vendor
 
Member#: 25194
Join Date: Sep 2002
Chapter/Region: RMIC
Location: Boulder, CO
Vehicle:
2008 Forester XT 5mt
Dark Gray

Default

One thing worth noting is the coolant temperature. If the car has a colder than stock thermostat then there is a chance the car is not warming up past the point where the ECU stops adding fuel for cold starts, tip-in enrichment, etc. I'm pretty sure this doesn't pertain to you, but I figured I'd chime in.

Stephen@iaperformance.com
www.facebook.com/iaperformance

Last edited by IA Performance; 04-15-2013 at 11:46 PM.
IA Performance is offline   Reply With Quote
Old 04-15-2013, 11:17 PM   #17
WhiteBgeye02
Scooby Specialist
 
Member#: 224785
Join Date: Sep 2009
Chapter/Region: MWSOC
Location: neenah
Vehicle:
2005 wrx-jdm207
i went black...

Default

get a tune to lean out cruise area. might as well buy a cheap car if you want mpgs and actually use what the car was made for. damn cheap ppl who cant afford an extra 4 bucks each fill up. winter fuel has more antifreeze additives as well which dont burn well so it takes more fuel from a larger throttle opening to keep the car going the same speed. also your intake air sensor is part of the maf so you should relocated it to post intercooler to make sure your so called changes u want to do are making a diff.
WhiteBgeye02 is offline   Reply With Quote
Old 04-15-2013, 11:32 PM   #18
K2e2vin
Scooby Newbie
 
Member#: 308481
Join Date: Jan 2012
Chapter/Region: South East
Location: Raleigh, NC
Vehicle:
2005 Legacy GT

Default

Quote:
Originally Posted by jthatch12 View Post
You also do realize that gas in the winter has more ethanol which burns quicker than gas.... Therefore worse gas milage. OP, please do not follow through on this. There is no correlation between your car getting better mileage and hot intake charge
I know there's a difference but I've never heard of ethanol specifically being the difference; only different formulas regarding vapor pressure(winter blends evaporate more easily).

Quote:
Originally Posted by Uncle Scotty View Post


go back to school and see where you are way outta yer mind here

we are talking about supercharged engines here.... and an optimized tune is what you want

not ****ing hot air intake

learn to tune and tune it yourself and you will see better mpg

and not blow it up with hot air intake
Can you tell me what exactly I'd look into? Also, regarding tune, wouldn't IAT be part of that? Plus, a tune doesn't mean it'll overcome physics. All of the digging I've done seem to lean towards warm air helping. Maybe "hot" wasn't the best term to use, but I was thinking of around 80F-90F(which is about average for the summer around here)...as some guys on ecomodder noting anything over 115F had a negative impact on FE; but of course I'd have to start logging to get a better picture.

Quote:
Originally Posted by IA Performance View Post
One thing worth noting is the coolant temperature. If the car has a colder than stock thermostat then there is a chance the car is not warming up past the point where the ECU adds fuel for cold starts, tip-in enrichment, etc. I'm pretty sure this doesn't pertain to you, but I figured I'd chime in.

Stephen@iaperformance.com
www.facebook.com/iaperformance
I'll definitely look into that. Is there a difference between the stock EJ207 and EJ255 thermostats? Right now I'm using the original LGT ECT and IAT trims.

If I seem stubborn, that's because you guys never really gave me any facts that disprove a warm air intake would affect the motor negatively. I can admit I'm wrong when shown the evidence, but so far there's nothing that has persuaded me.

As of right now, I'm not doing anything to the motor/car, but rather just an idea that I may pursue in the future.
K2e2vin is offline   Reply With Quote
Old 04-15-2013, 11:36 PM   #19
K2e2vin
Scooby Newbie
 
Member#: 308481
Join Date: Jan 2012
Chapter/Region: South East
Location: Raleigh, NC
Vehicle:
2005 Legacy GT

Default

Quote:
Originally Posted by WhiteBgeye02 View Post
get a tune to lean out cruise area. might as well buy a cheap car if you want mpgs and actually use what the car was made for. damn cheap ppl who cant afford an extra 4 bucks each fill up. winter fuel has more antifreeze additives as well which dont burn well so it takes more fuel from a larger throttle opening to keep the car going the same speed. also your intake air sensor is part of the maf so you should relocated it to post intercooler to make sure your so called changes u want to do are making a diff.
Thanks! I already have a "cheap" car that gets better MPGs. Problem is, it struggles up the mountain and gets stuck in non-ideal road conditions(Honda Accord...and yes I've tried taking it up the mountain). I'd probably choose to rewire the MAF and run an "external" IAT sensor if I have to go that route.

As stated before, fuel price isn't really an issue; I'm more interested in range.
K2e2vin is offline   Reply With Quote
Old 04-15-2013, 11:37 PM   #20
Uncle Scotty
Scooby Guru
 
Member#: 16200
Join Date: Mar 2002
Vehicle:
OK Houston
we have an Uncle

Default

Quote:
Originally Posted by WhiteBgeye02 View Post
get a tune to lean out cruise area. might as well buy a cheap car if you want mpgs and actually use what the car was made for. damn cheap ppl who cant afford an extra 4 bucks each fill up. winter fuel has more antifreeze additives as well which dont burn well so it takes more fuel from a larger throttle opening to keep the car going the same speed. also your intake air sensor is part of the maf so you should relocated it to post intercooler to make sure your so called changes u want to do are making a diff.
this is false....gasoline needs no antifreeze additives

go ahead....TRY to freeze gasoline.....ill wait..........


'winter gasoline' usually contains more oxygenates to help control smog/emissions

mpg can vary a LOT based on fuel

when i gas up in LA...the state...with no alcohol gas, i get at LEAST 3-4mpg better and usually 5-6mpg better than using 10% ethanol fuel in other places
Uncle Scotty is offline   Reply With Quote
Old 04-15-2013, 11:42 PM   #21
K2e2vin
Scooby Newbie
 
Member#: 308481
Join Date: Jan 2012
Chapter/Region: South East
Location: Raleigh, NC
Vehicle:
2005 Legacy GT

Default

Quote:
Originally Posted by Uncle Scotty View Post
when i gas up in LA...the state...with no alcohol gas, i get at LEAST 3-4mpg better and usually 5-6mpg better than using 10% ethanol fuel in other places
Just wondering, do you know a reliable site that lists gas stations with E-Free gasoline? I've used pure-gas.org and many of the stations they list end up being <10% ethanol.
K2e2vin is offline   Reply With Quote
Old 04-15-2013, 11:42 PM   #22
Uncle Scotty
Scooby Guru
 
Member#: 16200
Join Date: Mar 2002
Vehicle:
OK Houston
we have an Uncle

Default

ya bought/built the wrong car for mpg and ya gonna blow it up ****ing around with it

we can NOT teach you tuning here in this forum and i can guarantee that you will blow it up if you start ****ing around with things like the iat

i think the main reason that you get such better mpg in warmer weather is that the density of the air is being compensated for by the ecu by injecting more fuel and that keeps the a/f ratio correct and makes more power

and you dont know what you are doing with tuning a subaru..SPECIFICALLY subaru...you WILL blow it up
Uncle Scotty is offline   Reply With Quote
Old 04-15-2013, 11:54 PM   #23
IA Performance
NASIOC Vendor
 
Member#: 25194
Join Date: Sep 2002
Chapter/Region: RMIC
Location: Boulder, CO
Vehicle:
2008 Forester XT 5mt
Dark Gray

Default

K2e2vin - I believe the JDM thermostat is the same temp as the US.

As for the power loss, there are dyno charts floating around that show before and after with the stock air box assembly versus a short ram. The power delivery is more consistent with the stock air box since the short ram is sucking in air directly off of the hot radiator via the fans. Granted, it seems like your application is more for cruising so I'm not sure what the power affect would have in that case since dyno plots show wide open throttle. It seems logical that the engine bay air would be less desirable than air from the fender, but sometimes logic and reality are not the same.

www.facebook.com/iaperformance
IA Performance is offline   Reply With Quote
Old 04-16-2013, 02:24 AM   #24
K2e2vin
Scooby Newbie
 
Member#: 308481
Join Date: Jan 2012
Chapter/Region: South East
Location: Raleigh, NC
Vehicle:
2005 Legacy GT

Default

I didn't say I needed a lesson on tuning; it was a rhetorical question: tuning would include the possibility of changing IAT compensation. The point I'm trying to make here is I'm seeing higher MPG with the current IAT trim and warmer weather.

I don't know if you realized this but you just said I'm using less fuel due to the ECU injecting more fuel. I'll log injector PW and if the weather cools down, try to compare.

I can admit I'm a noob at tuning Subarus as this is my first one; hence why I'm asking questions before I do anything. My background is in Hondas and I understand there's different characteristics between those motors.

Thanks IA Performance. I'm really not interested in getting rid of the stock airbox at all. I may experiment with maybe a modified modified airbox panel that'll pull air from that area; but I'll definitely put a probe there first to see what temps are like in that area when driving before doing anything. Though, I didn't think about people running short rams; maybe I can find someone who is and see what type of figures they're seeing.

I'm actually looking forward to the summer to see if the figures I'm getting improve. That'll dictate whether or not I'll move on with trying to get a warm-air intake going.

Thanks for the comments and suggestions.
K2e2vin is offline   Reply With Quote
Old 04-16-2013, 06:40 AM   #25
quazimoto
Scooby Guru
 
Member#: 70395
Join Date: Sep 2004
Chapter/Region: MAIC
Location: Da-boonies,Va
Default

You are also not taking into account that colder weather = longer engine warm up time. There is also ECT fuel compensations as well that come into play. Running higher tire pressure and changing your driving habits will do far more for gas mileage than sucking in warm air.
quazimoto 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


All times are GMT -4. The time now is 09:14 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.