Welcome to the North American Subaru Impreza Owners Club Thursday July 19, 2018
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Normally Aspirated with bolt-on Forced Induction 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 02-20-2018, 12:05 PM   #1
sorrowfulkiller
Scooby Specialist
 
Member#: 170439
Join Date: Jan 2008
Location: Sioux Falls, SD
Vehicle:
I <3 Lamp

Default 99 Outback engine rebuild... boost?

I've got a 99 Outback with the ej25D phase 2 bottom end and phase 1 heads.

Bought the car recently and have pulled the engine with my wife to put all new gaskets in and re seal it back up. The stock pistons look fine and the bores have great crosshatching which is surprising considering it has 230k miles on it. Inside of the engine looks immaculate aside from carbon deposits. I have a gt2554 turbo sitting in my garage begging to be put into something. I know the stock compression ratio on this engine is something like 9.7:1 but if I put ej255 pistons in, it should drop to about 8.5:1. My thought is to possibly drop some stock ej255 pistons in that were pulled from a low mileage car getting forged pistons, then run stock ecu with the gt2554, wrx top mount, and a sti fuel pump for awhile. I'm planing on making my own uppipe and downpipe since I have a welder and fabrication experience. Then when I finish figuring out all the wiring I would drop in a microsquirt based diypnp ecu with some sti 565cc injectors.

Not looking for gobs of power obviously, but I do want some semblance of reliability for relatively cheap. Keep in mind I already have the injectors, ecu, and wrx top mount intercooler. I've yet to buy pistons for obvious reasons, same with the sti fuel pump.


My question is, would ej255 or ej257 stock pistons and stock ecu combo be reliable enough for a couple months without issue if I ran 91?




TLDR
I Have...

  • 99 outback with EJ25D, taken apart in garage
  • GT2554 Turbo from a saab 900 (7psi wastegate)
  • 565cc STI side feeds
  • 02 WRX top mount intercooler
  • DIYPNP Megasquirt ecu


I may need...

  • ej255 or ej257 pistons and rings, used probably.
  • wrx or sti fuel pump


Should I slap the turbo pistons in and run the stock ecu til I put the megasquirt in with the 565cc injectors?
Overall this only should cost me an additional $200 or so since I should be able to scrounge up enough steel pipe for the uppipe and downpipe.
* Registered users of the site do not see these ads.
sorrowfulkiller is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 03-30-2018, 02:31 PM   #2
pcampbell
Scooby Newbie
 
Member#: 437670
Join Date: Jan 2016
Vehicle:
2005 2.5 SC OB

Default

Sorry nobody replied earlier.

You should not run any boost with stock ECU. You can run the turbo pistons with stock ecu, you will just be down on power, but if you run boost with no engine management, you can destroy the motor obviously.

You might need to check to see if you need to run turbo rods also. I'm not sure if your 99 Rods are EJ255/257 length.

Last edited by pcampbell; 03-30-2018 at 02:51 PM.
pcampbell is offline   Reply With Quote
Old 04-03-2018, 09:15 PM   #3
91 RS RA
Scooby Newbie
 
Member#: 457410
Join Date: Oct 2016
Chapter/Region: International
Location: Christchurch, New Zealand
Vehicle:
1991 Legacy RS RA
White

Default

Also the EJ25D is not great with head gaskets, yes this can be improved with new and better head gaskets, but I wouldn't trust it with much boost.
And not have a correct ECU will make everything much worse as well.
What are you going to be using for boost control and what sort of max PSI are you thinking?
If you do want to do it, leave it at wastegate pressure, enjoy it till something goes on it and in the mean time save up for a nice turbo short block and then rebuild with better bottom end
91 RS RA 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 05:44 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2018 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.