Welcome to the North American Subaru Impreza Owners Club Thursday December 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 Technical > Normally Aspirated 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 06-13-2006, 07:05 PM   #51
zzyzx
Scooby Specialist
 
Member#: 815
Join Date: Jan 2000
Location: Florida
Vehicle:
2013 Boss 302 White
2000 2.5 RS Coupe Silver

Default

Might consider a link to some "reference" builds, like the most powerful documented NA 2.5 motor.
* Registered users of the site do not see these ads.
zzyzx is offline   Reply With Quote
Old 06-13-2006, 07:46 PM   #52
Matt Monson
Scooby Guru
 
Member#: 832
Join Date: Jan 2000
Chapter/Region: RMIC
Location: Teh Ghetto Garage, CO
Vehicle:
99 2.5RS, '85 911
'73 914 and 2012 BRZ

Default

http://forums.nasioc.com/forums/showthread.php?t=595740

Or one of the more powerful street legal ones running around.
Matt Monson is offline   Reply With Quote
Old 06-13-2006, 07:52 PM   #53
t3hWIT
Scooby Guru
 
Member#: 58779
Join Date: Apr 2004
Chapter/Region: MAIC
Location: **** Town
Vehicle:
95 STi RA (rhd)
98 Tacoma (300k Club)

Default

*subscribe*

Great post.
t3hWIT is offline   Reply With Quote
Old 06-13-2006, 08:08 PM   #54
badtaste
Scooby Newbie
 
Member#: 116636
Join Date: Jun 2006
Chapter/Region: MWSOC
Location: ohio
Vehicle:
2003 impreza
black

Default

wow someone has a lot of usefull time on their hands
badtaste is offline   Reply With Quote
Old 06-13-2006, 08:46 PM   #55
t3hWIT
Scooby Guru
 
Member#: 58779
Join Date: Apr 2004
Chapter/Region: MAIC
Location: **** Town
Vehicle:
95 STi RA (rhd)
98 Tacoma (300k Club)

Default

Just a note, I received an ebay underdrive pulley set from irishhockeypimp when I did an engine swap for him because he decided not to install it. It said its for a WRX, though I really don't think it will matter on my 2.2 I am swapping in. My point is, it is not just a smaller aluminum crank pulley, but it also has a smaller pulley for the alternator, so it will still spin at about the same speed. The only real question is how easily I can install the small pulley on the alternator.

Another thought... I spent almost 6 months worth of weekends and/or thursday allnighters, swapping an ej20 into a 99 RS. Much much more time and money was spent than originally planned. The car was incredibly quick IMO (though I haven't driven many quick cars). As stated, it does seem easier, quicker, and cheaper to build up a NA motor and out perform an EJ20T. One thing to keep in mind though, once your NA motor is built, its built, you've pretty much reached your limit. As for swapping engines, your car will be about as quick as a built NA, but you have the option of now going faster with more upgrades.

Just my .02. I'm doing a bit to this 2.2 before I put it in, but I will have a spare 1.8 sitting around, and a 2.5 shortblock in my basement collecting dust and needing a rebuild. Some of the classes I am taking at school will give me the option to do some headwork, so maybe one day...
t3hWIT is offline   Reply With Quote
Old 06-13-2006, 11:56 PM   #56
Rally_wgn
Scooby Specialist
 
Member#: 62629
Join Date: May 2004
Chapter/Region: MAIC
Location: Richmond,VA
Vehicle:
1996 OBS in Green
2.5 N/A w/ full exhaust

Default

MCL thanks for the comments. Rebuild the 2.5 and slap the 2.2 heads on it. Homework pffffttt... its over rated unless its fun.
Rally_wgn is offline   Reply With Quote
Old 06-14-2006, 08:54 PM   #57
t3hWIT
Scooby Guru
 
Member#: 58779
Join Date: Apr 2004
Chapter/Region: MAIC
Location: **** Town
Vehicle:
95 STi RA (rhd)
98 Tacoma (300k Club)

Default

I was thinking about throwing the 1.8 head on the 2.5 block. There are rumors to a boost in compression, and I think I can do something about how poor they flow, plus it will be dual port.

/highcompressionfrankenstein
t3hWIT is offline   Reply With Quote
Old 06-15-2006, 11:43 AM   #58
Matt Monson
Scooby Guru
 
Member#: 832
Join Date: Jan 2000
Chapter/Region: RMIC
Location: Teh Ghetto Garage, CO
Vehicle:
99 2.5RS, '85 911
'73 914 and 2012 BRZ

Default

Quote:
Originally Posted by mi_cistemz_loudr
I was thinking about throwing the 1.8 head on the 2.5 block. There are rumors to a boost in compression, and I think I can do something about how poor they flow, plus it will be dual port.

/highcompressionfrankenstein
Without even addressing the compression issue (too high for pump gas and stock EM) the bigger issue is that the bore differential is too great...
Matt Monson is offline   Reply With Quote
Old 06-15-2006, 12:37 PM   #59
ricochet
Driving Sports TV Staff
 
Member#: 15542
Join Date: Feb 2002
Location: Kirkland, WA
Vehicle:
1991 Legacy Sedan

Default

For N/A fans the next issue of Subiesport (August 06), which just hit press, covers the headwork on our Zero to Hero 2005 2.5RS and some other doo-dads. If getting everyting goes back into the car as it should, look for it to be on the cover of the October issue, along with dyno figures and details on how we tuned it.

Ryan Douthit, Publisher
Subiesport Magazine
http://www.subiesport.com
ricochet is offline   Reply With Quote
Old 06-15-2006, 12:40 PM   #60
Tim Sanderson
Scooby Guru
 
Member#: 6486
Join Date: May 2001
Chapter/Region: MWSOC
Location: S.E. wisconsin
Vehicle:
00 Impreza 2.5 RS
Blue Ridge Pearl

Default

I wonder why this is'nt a sticky yet.
Tim Sanderson is offline   Reply With Quote
Old 06-15-2006, 01:43 PM   #61
Rally_wgn
Scooby Specialist
 
Member#: 62629
Join Date: May 2004
Chapter/Region: MAIC
Location: Richmond,VA
Vehicle:
1996 OBS in Green
2.5 N/A w/ full exhaust

Default

Thanks for the sticky support Tim.

Ryan, I'm looking forward to my next issue of Subiesport. You guys are doing a great job. I can't wait til its a monthly issue ,hey why not weekly j/k
Rally_wgn is offline   Reply With Quote
Old 06-15-2006, 02:35 PM   #62
rob
n00b Moderator
Moderator
 
Member#: 811
Join Date: Jan 2000
Location: WA
Vehicle:
2000 RS-Ej20G
It tastes like burning

Default

My Road Dyno numbers with stock vs. Cobb CAI vs. Cobb CAI + MRT header (w/stock RS muffler).

http://forums.nasioc.com/forums/showthread.php?t=816371

If you look at my last post, I calculated my BSFC and the limits of stock injectors.

-Rob
rob is offline   Reply With Quote
Old 06-16-2006, 01:55 AM   #63
Patrick Olsen
NASIOC Supporter
 
Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
Vehicle:
1997 Legacy 2.5GT
QuickSilver Metallic

Default

Quote:
A 1998 Impreza weighed about 2800 lbs ( the coupe and sedan less, the wagons more). Based on 100whp a GC style impreza has a p/w ratio of 28:1.

A 2002 WRX weighs about 3100lbs, with 170whp its p/w ratio is 18.24. To equal that p/w ratio the GC owner only needs 152hp at the wheels. This can be achieved with cams, intake, headerback and EM. New these parts would run about $2000.
A couple of points. First, to use chassis dyno numbers to calculate lb/hp ratios is rather silly, since we'll never know how much those "stock" numbers are affected by drivetrain losses. Why throw additional unknown variables into the calculation when we already have perfectly good HP numbers to use? We already know the crank HP numbers, since those nice people at Subaru tell us what they are. Using 165hp and 2825# for the 2.5RS (advertised 1998 numbers) and 227hp and 3085# for the WRX (2002 sedan advertised numbers), the GC 2.5RS has ~17lb/hp, while a GD WRX has ~13.5lb/hp. Just using the correct numbers we've closed the gap from a 55% difference (28:1 vs 18:1) to a more realistic 26% difference (17:1 vs 13.5:1). Hooray!

Second, show me anybody that's making 50+hp over stock without touching the heads. To say one could go from 100whp to 152whp with just intake, exhaust, cams, and EM is extremely optimistic. I think Matt is the only one with dyno-proven results showing 50hp over stock, as he has head work done. I'm in the 40hp, maybe 45hp over stock range, again with head work done. So add a pretty healthy chunk on top of that $2000 to pay for the head work.

(As an aside, a "cat back exhaust" is everything after the cat. Hence, a "header back" would be everything after the header. I think what you really mean is a full exhaust - header, cat, midpipe, the whole shebang. Without the header, you're not gaining much of anything, as you already know.)

Anyway, to achieve the same ~13.5lb/hp of the stock WRX, one actually only needs ~208hp in that 2.5RS, which is around 40hp over stock. So, using the right numbers to do our initial calculations makes our job that much easier - we need 10 fewer HP to equal the WRX!

Some really good information summarized in this post, Rally_wgn, and I'm not trying to criticize (despite my typical smart ass tone). As an old school N/A type guy (one of the first here, I think) I just wanted to add some clarification.

Pat Olsen
'97 Legacy 2.5GT sedan (maybe a 3.0GT sedan in the next couple/few months?)

Last edited by Patrick Olsen; 06-16-2006 at 10:18 AM.
Patrick Olsen is online now   Reply With Quote
Old 06-16-2006, 09:35 AM   #64
Rally_wgn
Scooby Specialist
 
Member#: 62629
Join Date: May 2004
Chapter/Region: MAIC
Location: Richmond,VA
Vehicle:
1996 OBS in Green
2.5 N/A w/ full exhaust

Default

Thanks for your contribution Pat.
Rally_wgn is offline   Reply With Quote
Old 06-17-2006, 09:03 PM   #65
JoshP
Scooby Specialist
 
Member#: 94350
Join Date: Aug 2005
Chapter/Region: NESIC
Location: S. Maine
Default

I just wanted to comment about an s-afc. I looked at getting one but after reading about it I decided not to and heres why. the safc works by modifying the maf signal to change the ecus reading of air intake and tricking the ecu into adding or trimming fuel. Well if you have want to lean out the mixture, the ecu will be reading a lower maf number and calculate that as a lower load on the engine. This will cause the ecu to actually advance spark timing, something (im my case of high compression) that I absolutely do not want to do. So if you are considering a safc by itself, I suggest that you look to a better setup becuase the safc will effect timing, but not allow you to control it. Id love to hear what other people think of this, and if I am on track or not.
JoshP is offline   Reply With Quote
Old 06-18-2006, 08:15 PM   #66
WRX03
Scooby Specialist
 
Member#: 20744
Join Date: Jul 2002
Chapter/Region: MAIC
Location: Goodview, VA-SML
Vehicle:
05 Baja Regal Blue
03 WRX Little Red Wagon

Default

FYI: I emailed I-speed several monthes ago about my 05 Baja. They said they don't have a reflash for it and they aren't planning on trying. Don't know if this was just the Baja or all 05 N/A engines-didn't ask at the time. (if anyone knows post it)
WRX03 is offline   Reply With Quote
Old 06-19-2006, 01:17 AM   #67
RiverDog
Scooby Newbie
 
Member#: 65661
Join Date: Jul 2004
Chapter/Region: MWSOC
Location: Chicago
Vehicle:
126 whp, 141 wtq
That's how I roll

Default

as a guy who will be referring back to this thread many times for my BE legacy, please sticky.
RiverDog is offline   Reply With Quote
Old 06-19-2006, 04:20 AM   #68
Rockstar25
Scooby Specialist
 
Member#: 91833
Join Date: Jul 2005
Chapter/Region: MWSOC
Location: Indy/Purdue University
Vehicle:
98 black RS-Sold
Indy Forum's Kid

Default

If ordering the OBX RS header from sparktec in the comment section of the order if you mention that you are an RS25.com member you can get it for $300 shipped
Rockstar25 is offline   Reply With Quote
Old 06-19-2006, 09:53 AM   #69
Siper2
Scooby Guru
 
Member#: 1134
Join Date: Mar 2000
Chapter/Region: MAIC
Location: Dillsburg, PA
Vehicle:
2007 BMW 328xi wagon
Silver

Thumbs up

This is one of those rare threads, that unfortunately take years of speculation to formulate into doctrine, but we're all thankful when it finally appears.



=S2=
Siper2 is offline   Reply With Quote
Old 06-19-2006, 12:03 PM   #70
Rally_wgn
Scooby Specialist
 
Member#: 62629
Join Date: May 2004
Chapter/Region: MAIC
Location: Richmond,VA
Vehicle:
1996 OBS in Green
2.5 N/A w/ full exhaust

Default

Thanks Siper.
Rally_wgn is offline   Reply With Quote
Old 06-19-2006, 12:19 PM   #71
Siper2
Scooby Guru
 
Member#: 1134
Join Date: Mar 2000
Chapter/Region: MAIC
Location: Dillsburg, PA
Vehicle:
2007 BMW 328xi wagon
Silver

Default

No sweat.
Siper2 is offline   Reply With Quote
Old 06-20-2006, 08:54 PM   #72
Rally_wgn
Scooby Specialist
 
Member#: 62629
Join Date: May 2004
Chapter/Region: MAIC
Location: Richmond,VA
Vehicle:
1996 OBS in Green
2.5 N/A w/ full exhaust

Default

Hoping for a sticky bump.
Rally_wgn is offline   Reply With Quote
Old 06-20-2006, 09:52 PM   #73
Siper2
Scooby Guru
 
Member#: 1134
Join Date: Mar 2000
Chapter/Region: MAIC
Location: Dillsburg, PA
Vehicle:
2007 BMW 328xi wagon
Silver

Default

I'll see if North Ursalia can do it for you.
Siper2 is offline   Reply With Quote
Old 06-20-2006, 11:04 PM   #74
Rally_wgn
Scooby Specialist
 
Member#: 62629
Join Date: May 2004
Chapter/Region: MAIC
Location: Richmond,VA
Vehicle:
1996 OBS in Green
2.5 N/A w/ full exhaust

Default

thx siper
Rally_wgn is offline   Reply With Quote
Old 06-29-2006, 01:39 PM   #75
Rally_wgn
Scooby Specialist
 
Member#: 62629
Join Date: May 2004
Chapter/Region: MAIC
Location: Richmond,VA
Vehicle:
1996 OBS in Green
2.5 N/A w/ full exhaust

Default

What does a man need to do to get a thread stickied?
Rally_wgn 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
Build-up plans, please critique bongchild Normally Aspirated Powertrain 11 09-27-2005 04:25 PM
OT: Please Critique my resume DrDRum Off-Topic 25 07-20-2005 05:48 PM
Please critique this computer... GarySheehan Off-Topic 67 09-13-2004 07:40 PM
OT please critique my resume suprsubepower Off-Topic 17 03-23-2004 05:15 PM
IT/Developers please critique my resume maaw Off-Topic 9 08-22-2003 04:16 PM


All times are GMT -4. The time now is 12:46 AM.


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.