Welcome to the North American Subaru Impreza Owners Club Friday September 19, 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 > Subaru Conversions

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 10-22-2012, 08:10 PM   #1
fullCircling
Scooby Newbie
 
Member#: 290547
Join Date: Aug 2011
Location: Southern Tier NY
Default 97 Legacy - FULL '08 STI Conversion possible? (stock ECU, VCD, 4 ch ABS, si-drive)

I want to run all of the stock '08 sti systems in a '97 legacy. VDC, si-drive, 4 channel ABS, etc. I'm good with wiring, and I'll be doing it in pieces if its possible. So, is it possible?

The first stage is to get the bare minimum in the car to PROPERLY run the '08+ STI ECU with dual AVCS heads.

What's the minimum I'd need to convert to properly run dual avcs with the stock ECU? Can any of the systems that are ECU (VDC, si-drive, ABS?) controlled be disabled by a competent tuner until I install them?

This is a serious discussion, I'm not some kid who has no idea of the amount of labor involved. I got time and resources to get 'r completed. Any real help would be appreciated.

-Jon
* Registered users of the site do not see these ads.
fullCircling is offline   Reply With Quote
Old 10-24-2012, 05:42 PM   #2
robduf
Scooby Newbie
 
Member#: 171837
Join Date: Feb 2008
Chapter/Region: NWIC
Location: Milton, WA
Vehicle:
1999 2.5 RS
Orange-Black

Default

I think you are going to run into the same issues us Impreza RS owners have when doing a conversion to STi. Harness is so different that you are have to do a full swap or a lot of rewiring. Like staying up till 3am all week crying because nothing is working right lots. I believe you have an OBDI (that changes to OBDII in 1998) That could be an issue for your areas emissions requirements, you’ll want to do some research there.

Thinks to investigate:
• Custom brake lines for the ABS have to use the STi’s system for this.
• Rear suspension shock mounts might be too small for the new STi rear end.
• Custom peddle mounting for fly by wire
• You’ll need to use the STi Dash that will need to be custom fabricated.
• You aren’t going to be able to use the STi gas tank and evaporator system, which will toss a CEL, will need custom work.
• You’ll need to do some custom pipe work because the exhaust is longer on the Legacy.

This is me just talking out of my ass about it; all my swaps have been done on 1999 to 2001 RS from 2004-2007 donor cars.

I’d love to see it work out. Do you already have a 08 donor car picked out?
robduf is offline   Reply With Quote
Old 10-26-2012, 03:09 AM   #3
fullCircling
Scooby Newbie
 
Member#: 290547
Join Date: Aug 2011
Location: Southern Tier NY
Default

nah, im prob not gonna get a donor car until later. im gonna do the work in stages.

phase 1: gonna build a dual avcs 257 motor first, build a custom wiring harness for it and the stock 08+ ecu, and install the bare minimum to make the ecu run the dual avcs correctly. get a tune, and get whatever i can disabled on the ecu so there's less to install to get the car to run. i may even run higher compression cp pistons, so i can get away with running it n/a until i piece together the turbo stuff.

phase 2:find a rolled or totalled 08 shell with no motor (possibly one that still has a trans), and start swapping stuff like the 4 channel abs system, suspension, dccd bits, cluster, si drive etc.

ultimately, i want a very capable, somewhat sleeper car that can tackle anything. mud, rain, snow, DDing, autox etc. a low key subaru that is cheaper on insurance, but will perform just as well as a new sti. full sti si drive and dccd controls, complete w/ sti cluster in the same legacy dash, the newer 4 channel abs system, and front and rear helical lsds. then maybe later on if i come across a better, newer shell i'll swap it all over. i'll make all of the wiring easy to work on and transfer to another car if need be.

that's the plan anyways, and you know how those usually go...hahaha
fullCircling is offline   Reply With Quote
Old 10-26-2012, 03:17 PM   #4
MMY MSL
Scooby Newbie
 
Member#: 335135
Join Date: Oct 2012
Chapter/Region: NWIC
Location: PDX
Vehicle:
2004 WRX
Silver

Default

From what I've read the 08+ STI uses a canbus computer system that is markedly different from the 04-07 STI, the ECU requires readings from a number of sensors placed around the body of the car constantly to run properly. If the sensors are missing, or not reading properly you are probably going to have all kinds of CELs and gremlins on your hands. While wiring it might be possible, unless you're a professional with a lot of spare time and knowledge I can't see why you'd opt to tackle this.

Personally I also don't see enough benefit from the dual AVCS to justify all the extra risk and headache that the swap might constitute vs a single AVCS ej255 or ej257. And this statement: "ultimately, i want a very capable, somewhat sleeper car that can tackle anything. mud, rain, snow, DDing, autox etc. a low key subaru that is cheaper on insurance, but will perform just as well as a new sti." doesn't seem to indicate a need to try something more complex than a built EJ25 with an upgraded turbo. If you're sold on the DCCD system, look at DCCDpro, it's an aftermarket controller available in manual or automatic for the 04-07 STI 6 speeds.

Also I believe 96+ USDM cars are all OBDII.

That's my 2 cents.
MMY MSL is offline   Reply With Quote
Old 10-27-2012, 12:02 PM   #5
PHATsuby
Scooby Guru
 
Member#: 13617
Join Date: Dec 2001
Chapter/Region: MWSOC
Location: MN
Vehicle:
2001 Legacy GT back
to stock is a project too

Default

Not worth going for an 08 in a 97 legacy, the 07 STi subframes front and rear will bolt up to your 97 with no issue where as the 08+ is very different and will not bolt up in the rear at all making it not possible to use the rear suspension/hubs etc that is also needed to work with the ABS Canbus system.

Save yourself a lot of headaches and just go 07 Sti at the newest IMO.

Ben
PHATsuby is offline   Reply With Quote
Old 10-29-2012, 12:25 PM   #6
05subysti
Scooby Specialist
 
Member#: 268190
Join Date: Dec 2010
Chapter/Region: TXIC
Location: central tx
Vehicle:
2005 STi
RWD, 18x10.5/12.5s

Default

^^^ he is right. just go with an 07 sti power and drivetrain. youll also have the best gear ratio as well.
05subysti is offline   Reply With Quote
Old 11-23-2012, 05:03 PM   #7
fullCircling
Scooby Newbie
 
Member#: 290547
Join Date: Aug 2011
Location: Southern Tier NY
Default

I just picked up a set of dual avcs heads out of a 2010 LGT, anyone know what ECU I should use?
fullCircling is offline   Reply With Quote
Old 11-23-2012, 05:07 PM   #8
fullCircling
Scooby Newbie
 
Member#: 290547
Join Date: Aug 2011
Location: Southern Tier NY
Default

...aftermarket or oem. whatever will run the dual avcs properly
fullCircling is offline   Reply With Quote
Old 11-23-2012, 07:01 PM   #9
PHATsuby
Scooby Guru
 
Member#: 13617
Join Date: Dec 2001
Chapter/Region: MWSOC
Location: MN
Vehicle:
2001 Legacy GT back
to stock is a project too

Default

No offense but do you have an actual strategy and know how these parts will fit together?

The 2010 LGT has a drive gear on the heads to drive the oil sump for the turbo since it is mounted below the engine, just curious if you know if that will matter or if it's easy to block off because it may cause headaches that would be avoided with 08 STi heads.

I think aftermarket is the only way to go at this point really, it will be quite an ordeal to get the canbus system working and if you are mixing and matching parts that could add other twists.

Ben
PHATsuby is offline   Reply With Quote
Old 11-23-2012, 07:31 PM   #10
KONKILR
Scooby Specialist
 
Member#: 3190
Join Date: Dec 2000
Chapter/Region: MAIC
Location: Flintstone,md.
Vehicle:
2004 Impreza TS and
the Suxass racing mobile!

Default

The 08 STI ECU uses Immobilizer. It will not work without the other modules present and the keys meant for the system. AS well as the ignition cylinder with antenna. You would have to swap the entire wiring from a donor car. The GR chassis is greatly different than the earlier GD or GC's. It will make the swap extremely difficult. It is much more cost effective to swap in an 04 STI engine and driveline. If you want the dual AVCS you can get an aftermarket controller to control the exhaust cams along with the 04 ECU. You can swap in the abs from an 04 STI as well. You may need to make custom brake lines to fit the legacy chassis. The SI drive is just a silly gadget so not worth the hassle of installing, all it does is change the throttle profile.

jake
KONKILR is offline   Reply With Quote
Old 11-24-2012, 02:35 PM   #11
fullCircling
Scooby Newbie
 
Member#: 290547
Join Date: Aug 2011
Location: Southern Tier NY
Default

Quote:
Originally Posted by PHATsuby View Post
No offense but do you have an actual strategy and know how these parts will fit together?
No, I'm still coming up with a strategy by posting threads like this. See, you've just informed me about the oil scavenging system on the heads, someone else has I know that an '07 sti subframes will bolt right up, and yet another has said that si drive isn't worth adding.

See? It's coming together, I got this. Thanks for the help guys.

Last edited by fullCircling; 11-24-2012 at 02:41 PM.
fullCircling 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 01:06 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.