Welcome to the North American Subaru Impreza Owners Club Sunday December 28, 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 01-13-2001, 12:26 PM   #1
gimpster
Scooby Specialist
 
Member#: 2295
Join Date: Sep 2000
Chapter/Region: NWIC
Location: Seattle
Question JDM vs USDM EJ20

What's the difference between the two? Or is there? I've heard that with the USDM EJ20 if I try to boost it more than the stock 13.5 PSI then I will have problems with the cam belt tensioner bearing failing. Also I've been told that with high boost I'll have problems with piston slap in the #4 cylinder. I'm new to subaru's and boxer engines and I'm waiting for my WRX to get delivered. In the mean time I'm trying to plan out my mods. I want to be at 300HP minimum, preferably 350-400HP. Can anyone tell me how they get around the above listed problems on the JDM spec EJ20 or is the USDM spec EJ20 different than the JDM spec? Also, what other problems should I expect when trying to reach those kind of HP numbers and what would you recommend as the "safest" way to get there? Sorry for the length of the post but any help would be immensly appreciated.

[This message has been edited by gimpster (edited January 13, 2001).]
* Registered users of the site do not see these ads.
gimpster is offline   Reply With Quote
Old 01-15-2001, 05:58 PM   #2
gimpster
Scooby Specialist
 
Member#: 2295
Join Date: Sep 2000
Chapter/Region: NWIC
Location: Seattle
Post

TTT
gimpster is offline   Reply With Quote
Old 01-15-2001, 07:08 PM   #3
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

Cool

Gimpster,
I try not to be of the "do a search" ilk, but I couldn't even begin to cover all the differences and optiions here. You should to some research on the generations and manifestations of the EJ20.

That said, a base USDM and JDM EJ20 will not be different internally. It is the Sti and RA versions that get HP goodies. With what you want (350-400) I have one suggestion:
Blueprinting! RA's have different cranks, cylinders, rods, spring, etc. etc. To build an engine ready for that boost you need to really build it and not just mod your stock WRX engine.
Or, you could just do an EJ25 swap and buy one of Shiv's kits....Happy researching.
Matt Monson is offline   Reply With Quote
Old 01-15-2001, 09:03 PM   #4
Digital_Boy
Scooby Specialist
 
Member#: 730
Join Date: Jan 2000
Post

Or you can go to Rally Knight and get an EJ25 CARB pending turbo kit with a Motec for a little more!
Digital_Boy is offline   Reply With Quote
Old 01-16-2001, 12:38 AM   #5
kaminari
Scooby Specialist
 
Member#: 1781
Join Date: Jul 2000
Location: Hayward, CA, US
Vehicle:
2000 2.5RS
Blue Ridge Pearl

Post

who/where is rally knight?
kaminari is offline   Reply With Quote
Old 01-16-2001, 02:39 PM   #6
gimpster
Scooby Specialist
 
Member#: 2295
Join Date: Sep 2000
Chapter/Region: NWIC
Location: Seattle
Post

Thanks for the replies. I've been doing a lot of research since posting this and I think that if I build an engine the way I'm going to go is with an EJ22 because of the closed deck design. And since I know there is already another thread going on this right now, I'll just read up on that and dig around some more. Thanks again for your help.
gimpster is offline   Reply With Quote
Old 01-16-2001, 02:47 PM   #7
ColinL
Scooby Guru
 
Member#: 114
Join Date: Jul 1999
Chapter/Region: MWSOC
Location: Wichita, KS and Whoring, OT
Vehicle:
'03 Evo, Rice White
'01 Erion CBR 929

Post

I disagree. If you want closed deck, have Trey sell you a closed deck EJ25.

The big difference between the JDM and US domestic EJ20 is the US' lack of a variable valve timing cylinder head. Those tumble ports to improve cold-start emissions also look suspiciously to me like high RPM flow impediments.
ColinL is offline   Reply With Quote
Old 01-16-2001, 03:44 PM   #8
apexi
Scooby Newbie
 
Member#: 3593
Join Date: Jan 2001
Location: Houston, TX
Post

So what you are saying is that the US version of EJ20 and the JDM version of EJ20 basically has the same internals? Same pistons, rods, cranks, etc? Thanks.
apexi is offline   Reply With Quote
Old 01-16-2001, 03:50 PM   #9
ColinL
Scooby Guru
 
Member#: 114
Join Date: Jul 1999
Chapter/Region: MWSOC
Location: Wichita, KS and Whoring, OT
Vehicle:
'03 Evo, Rice White
'01 Erion CBR 929

Post

No clue.
ColinL is offline   Reply With Quote
Old 01-16-2001, 03:52 PM   #10
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

Wink

Colin,
As usual, you are correct. I should have been more clear that the USDM EJ20 we are about to get is the same as base EJ20's that have been in WRX's for the last few years in JDM and elsewhere..

Apexi,
as I mentioned above, STi and Type RA's have different internals,only the base models are the same.
Matt Monson is offline   Reply With Quote
Old 01-16-2001, 04:28 PM   #11
gimpster
Scooby Specialist
 
Member#: 2295
Join Date: Sep 2000
Chapter/Region: NWIC
Location: Seattle
Post

Someone suggested to me a JDM EJ22 with 2.5 heads. Would this be better or worse than a closed deck EJ25 for a big turbo?
gimpster is offline   Reply With Quote
Old 01-16-2001, 04:41 PM   #12
ColinL
Scooby Guru
 
Member#: 114
Join Date: Jul 1999
Chapter/Region: MWSOC
Location: Wichita, KS and Whoring, OT
Vehicle:
'03 Evo, Rice White
'01 Erion CBR 929

Post

Displacement wins in my book when you start talking big bucks.

So long as you can source a forged 79mm crankshaft, go for 2.5L. And if not, still use the 97-100mm bore!
ColinL is offline   Reply With Quote
Old 01-16-2001, 07:35 PM   #13
Basshead
Scooby Specialist
 
Member#: 112
Join Date: Jul 1999
Chapter/Region: NWIC
Location: Snohomish, WA
Vehicle:
2011 Jetta TDI
Black

Post

well gimpster...if money is not an option a fully built closed deck 2.5 is impossible to beat..can we say JUN 2.5 Imp in new zealand? But out of the box a 2.2 is already closed deck...then 2.5 heads for more grunt...perhaps i was unclear before..sorry
Basshead is offline   Reply With Quote
Old 01-16-2001, 11:22 PM   #14
gimpster
Scooby Specialist
 
Member#: 2295
Join Date: Sep 2000
Chapter/Region: NWIC
Location: Seattle
Post

Basshead, I'm a little unclear on what the 2.5 heads do for the EJ22. Do they raise/lower compression or increase displacement or are they just a stronger head to use?

Colin(or anyone else): do you have any links to sites that list out the raw specs of the different Subaru engines (bore, stroke, rod length, compression ratio, etc.)
gimpster is offline   Reply With Quote
Old 01-17-2001, 08:54 AM   #15
ColinL
Scooby Guru
 
Member#: 114
Join Date: Jul 1999
Chapter/Region: MWSOC
Location: Wichita, KS and Whoring, OT
Vehicle:
'03 Evo, Rice White
'01 Erion CBR 929

Post

gimpster, I have yet to see that type of data on the web. Not many people possess those manuals, and since they paid for them they generally aren't willing to distribute the information freely.
ColinL is offline   Reply With Quote
Old 01-17-2001, 09:40 AM   #16
rpone605
Scooby Specialist
 
Member#: 1669
Join Date: Jun 2000
Location: Cleveland, Ohio
Vehicle:
2004 WRX Sport Wagon
Silver

Post

ej25 heads on a ej22 block??

hmm..makes me think of 305 V8 heads on a 350 V8 block...it's supposedly jumps the compression on the motor...and still keeps it at stock specs (supposedly).

you thinking along those lines?
rpone605 is offline   Reply With Quote
Old 01-17-2001, 09:45 AM   #17
ColinL
Scooby Guru
 
Member#: 114
Join Date: Jul 1999
Chapter/Region: MWSOC
Location: Wichita, KS and Whoring, OT
Vehicle:
'03 Evo, Rice White
'01 Erion CBR 929

Post

Guys there were two EJ22 turbos.

One was the early 90's Legacy Turbo (before the FIA reduced Group A displacement from 2.2L to 2.0L). The cylinder heads on it suck, and yes either the DOHC or SOHC EJ25 heads would be an improvement, although DOHC would lower the compression ratio even further. The SOHC head is nearly identical in operation but it doesn't flow the same.

The other was the 22B motor, which was nothing like the Legacy Turbo at all. It used an STi4 cylinder head, DOHC and the best factory casting Subaru had at the time.

[This message has been edited by ColinL (edited January 17, 2001).]

[This message has been edited by ColinL (edited January 17, 2001).]
ColinL is offline   Reply With Quote
Old 01-17-2001, 10:54 AM   #18
Cacophony
Scooby Newbie
 
Member#: 213
Join Date: Aug 1999
Location: Philly, PA
Vehicle:
2004 Mazda RX-8
Black

Post

How about a legacy turbo shortblock with Sti heads, turbo, etc.. Sounds like a recipe for 280+hp to me

The poor man's 22b!
Cacophony is offline   Reply With Quote
Old 01-17-2001, 02:25 PM   #19
ColinL
Scooby Guru
 
Member#: 114
Join Date: Jul 1999
Chapter/Region: MWSOC
Location: Wichita, KS and Whoring, OT
Vehicle:
'03 Evo, Rice White
'01 Erion CBR 929

Post

One can be bought from US-based engine remanufacturers in long- or short-block form for relatively little cash.

The other is mega-expensive and supposedly requires the VIN from an STi to purchase direct from STi in Japan.

ColinL is offline   Reply With Quote
Old 01-17-2001, 03:18 PM   #20
Cacophony
Scooby Newbie
 
Member#: 213
Join Date: Aug 1999
Location: Philly, PA
Vehicle:
2004 Mazda RX-8
Black

Post

The legacy turbo block isn't a "bad" engine. In fact, the block is quite good. It's just been cursed with ill-flowing heads.

Put on some proper heads and you're in business
Cacophony is offline   Reply With Quote
Old 01-17-2001, 04:22 PM   #21
gimpster
Scooby Specialist
 
Member#: 2295
Join Date: Sep 2000
Chapter/Region: NWIC
Location: Seattle
Post

what kind of heads would you recommend for the Legacy EJ22? Roughly what kind of cost would we be talking? Or could you just have the stock head Extrude Honed?

[This message has been edited by gimpster (edited January 17, 2001).]
gimpster is offline   Reply With Quote
Old 01-17-2001, 05:11 PM   #22
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

Post

Well...
Cobb's reworked heads sell for a couple of grand if you want to go the full monty. A stock EJ22 or EJ25 head that you can install cams in yourself and whatever upgrade should be far less than a grand. And I am sure there are many options in between.
There is currently a tuner here in Nor-Cal starting a project with a mid 90's Legacy shortblock, but they are keeping the details
under wraps for now...
Matt Monson is offline   Reply With Quote
Old 01-17-2001, 11:03 PM   #23
Aspen
Scooby Specialist
 
Member#: 145
Join Date: Aug 1999
Chapter/Region: MWSOC
Location: The Windy City
Vehicle:
Banned to
Housework for Summer

Post

I think their needs to be a distinction made between using the 2.5L heads on a N/A 2.2L block(ej22) and using 2.5L heads on a turbocharged 2.2L block(ej22) when talking about this posting.

It seems like their are both questions being asked at the same time.

Just a little clarification...
Aspen is offline   Reply With Quote
Old 01-18-2001, 01:34 AM   #24
gimpster
Scooby Specialist
 
Member#: 2295
Join Date: Sep 2000
Chapter/Region: NWIC
Location: Seattle
Question

Colin: how can you tell the difference between the "bad" Legacy EJ22 and the "good" 22B EJ22 when shopping for an engine?

[This message has been edited by gimpster (edited January 17, 2001).]
gimpster is offline   Reply With Quote
Old 01-18-2001, 05:00 PM   #25
gimpster
Scooby Specialist
 
Member#: 2295
Join Date: Sep 2000
Chapter/Region: NWIC
Location: Seattle
Post

Could you go ahead and clarify it for me then, Aspen?
gimpster 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
Version 7 vs. USDM EJ20 Intake Manifold? D-Speed 2.5 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 7 08-16-2005 02:07 AM
Apexi S-afc II - JDM vs USDM awd4ever Normally Aspirated with bolt-on Forced Induction Powertrain 18 03-16-2004 12:29 AM
JDM vs USDM ScoobyDoRex Off-Topic 9 08-06-2003 06:39 PM
ej22 vs usdm ej20 STEALTH-WRX Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 19 08-15-2002 04:16 PM
factory STOCK JDM vs USDM upipe pics christoph1371 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 6 06-11-2002 12:25 PM


All times are GMT -4. The time now is 02:48 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.