Welcome to the North American Subaru Impreza Owners Club Sunday July 13, 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 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 04-03-2002, 01:23 AM   #1
redmeanie
Scooby Newbie
 
Member#: 15702
Join Date: Feb 2002
Chapter/Region: TXIC
Location: Houston,TX
Vehicle:
2001 2.5 RS-T LINK'D
911verion2.0TT (soon)

Question EJ20 or EJ25 for Turbo Project.....2001 2.5RS

Trying to figure out if Im better off modifying my EJ25 lower end, pistons, rods etc. with Cobb turbo heads and cam with my stage III Turbo and standalone computer or mod out an EJ20...Ive heard the EJ20 is a Stronger engine?
* Registered users of the site do not see these ads.
redmeanie is offline   Reply With Quote
Old 04-03-2002, 01:42 AM   #2
LVSUBARU
Scooby Specialist
 
Member#: 4520
Join Date: Feb 2001
Location: LAS VEGAS
Vehicle:
93 STi V.4 RA
www.flat4lv.com

Default

I personally prefer the EJ25. I've driven both. I think the EJ25's low end torque mates with the turbo very well!!! The low end torque raly makes up for any turbo lag!
I hate turbo lag!!!!
I don't know what low compresion pistions will do to the EJ25's low end. If that's even what you plan to do. I prefer high compression and low boost. That way you get the bottom end of the stroked out EJ25 motor, plus the top end pull of the turbo!!!
LVSUBARU is offline   Reply With Quote
Old 04-03-2002, 11:52 PM   #3
STiTuner
Scooby Specialist
 
Member#: 5778
Join Date: Apr 2001
Chapter/Region: South East
Vehicle:
09 135i
Jet Black

Default

an EJ25 will be a lot more fun to drive

but I think the EJ 20 m,ight be a little bit easier on the tranny.

Brad
STiTuner is offline   Reply With Quote
Old 04-04-2002, 01:28 PM   #4
spacemonkey
Scooby Specialist
 
Member#: 16435
Join Date: Mar 2002
Location: Chattanooga TN
Default

What are the prices of the two engines? approximate and where would be a good place to get them?
spacemonkey is offline   Reply With Quote
Old 04-04-2002, 03:22 PM   #5
MY99 2.5GT
Scooby Specialist
 
Member#: 5030
Join Date: Mar 2001
Chapter/Region: MAIC
Location: Martinsburg, WV, USA
Vehicle:
1999 Legacy 2.5GT
05 Legacy GT 06 Armada

Default

Honestly it depends on what kind of power you are looking for. Also if you decide to turbo the EJ25 that is in your car currently you won't have spend the $ on a new engine. Look at it this way

Cost to correctly turbo the EJ25 currently in your car = about $6000-$7000 just for hardware. Power output would probably 250-270 hp at the flyweel.

Cost for a JDM EJ20 (230-250hp stock) = about $2300-$2500. If you decide to get the JDM tranny add another $800 and don't forget the front diff for the tranny. Spend another $4000 modding the JDM EJ20 and you could have a car that produces above 250hp to the wheels. I road in a friends WRX with about $5000 worth of power mods. He dynoed at 278 horsepower to the wheels.

Lag really isn't an issue with a modded EJ20. Go with a larger TMIC and a quick ball bearing turbo and you can almost eliminate lag alltogether and still get more overall power from an EJ20 cheaper then you can from an EJ25.

Now if you are planning to buy a seperate EJ25 to turbo tune, the JDM EJ20 turbo motor is by far a cheaper option.
MY99 2.5GT is offline   Reply With Quote
Old 04-04-2002, 09:50 PM   #6
aek
Scooby Newbie
 
Member#: 13888
Join Date: Jan 2002
Location: Formosa Taiwan
Vehicle:
2002 2.5 RS Black
:( sold ( now GC8 )

Default

So you mean about less than $4000, I can turn my car from 25RS to WRX's EJ20 tirbo ?? How about the laber fee?

where can I do this kind of swap for my MY02 RS?

I'm interested .
aek is offline   Reply With Quote
Old 04-04-2002, 10:20 PM   #7
MattC
Scooby Specialist
 
Member#: 158
Join Date: Aug 1999
Chapter/Region: NESIC
Location: CT
Vehicle:
2011 STi
PBP 1999 2.5RS RBP

Default

There is two sides to every story, and your going to hear both over and over again. This topic has really been beaten to death.

To make your RS have over 300HP at the crank and even more torque at any RPM is going to take a lot of bank. I don't even want to imagine how much money I have invested in my beast. Not to say it isn't worth it, but its a lot of money. I stuck with the EJ25 and am very happy with it. This isn't the case for everyone though. Many have blown motors, afterwards going the route of the Legacy Turbo EJ22. This motor will mat up to EJ25 heads, but it really screws up the power curve.

An EJ20 swap isn't nearly as easy as it looks or sounds either. If you are looking at this route, I suggest selling your car and starting fresh with a WRX. You can go to Rallispec who charges over 10 grand for a full STi conversion. This is the only way to do it, if you don't know exactly what your are doing.

I personally don't like the idea of getting a used motor, especially one that was involved in a accident. A guy I know did a wonderful STi swap. Little did he know the crank had been damaged by the previous owners crash. The motor blew up leaving back at square one.

It is however safe to say that the EJ25 is more responsive, has a much more linear power curve, and can last over 35k miles of very hard abuse. Proper engine management is key, as well as having a proper tuner.

Basically you take a risk either way. All I can say is Good Luck

MattC
MattC is offline   Reply With Quote
Old 04-04-2002, 11:23 PM   #8
AzNStiImpreza
Scooby Specialist
 
Member#: 17181
Join Date: Apr 2002
Chapter/Region: MAIC
Location: "fredneck", Maryland
Vehicle:
2013 Scion FRS
Whiteout

Default Hmm... Project impreza 2.5rs

Hmm.. ive read an issue of sport compact car where one of their projects was to turbo charge an 2001 impreza 2.5rs coupe. It was the issue with all those WRX cars. but n e way, all SCC did to the 2.5rs was put a turbo with 8-9 psi. they wanted to dyno the car so they took out AWD and made a FWD impreza to Dyno easily. They got 300hp to the wheels and 299 lbs/ft of torque with just 9 psi turbo!!!!! so, the 2.5rs is a powerful engine indeed. then again, the EJ20 is the J-spec engine for imprezas and WRX STi are crazy when it comes to Power. say, 500hp easily. 2.5 liters compared to 2.0 liters. i think both engines are very good to hook-up. It might cost a little more to get the EJ25 the power you all want. i think jsut rol ewith the 2.5 liter and if it blows up, get a EJ20. that is wut i am probably going to do. if u want an easy job, jsut swap for ej20.
AzNStiImpreza is offline   Reply With Quote
Old 04-04-2002, 11:58 PM   #9
LVSUBARU
Scooby Specialist
 
Member#: 4520
Join Date: Feb 2001
Location: LAS VEGAS
Vehicle:
93 STi V.4 RA
www.flat4lv.com

Default

Quote:
Originally posted by MY99 2.5GT

Cost for a JDM EJ20 (230-250hp stock) = about $2300-$2500.
Does that include the wiring harness and ECU?? Can you use the 2.5RS instrument cluster? That sound to good to be true!!
LVSUBARU is offline   Reply With Quote
Old 04-05-2002, 12:02 AM   #10
XT6Wagon
Scooby Specialist
 
Member#: 524
Join Date: Nov 1999
Location: WA
Vehicle:
04 STi
White

Default

If you shop around in getting your 1/2 cut you can do it cheap. I am getting a Sti V1 (250ps) for $2K + shipping. Other places offered me a variety of engine and tranny combo's for under $2K.

A guy recently was E-baying a Legacy single turbo drivetrain and the reserve was a mere $1300. POS deal for me since I would need alot of extra stuff for my application, but a great deal for anyone with a Legacy or impreza that already has the Hydo clutch.
XT6Wagon is offline   Reply With Quote
Old 04-05-2002, 03:30 PM   #11
MY99 2.5GT
Scooby Specialist
 
Member#: 5030
Join Date: Mar 2001
Chapter/Region: MAIC
Location: Martinsburg, WV, USA
Vehicle:
1999 Legacy 2.5GT
05 Legacy GT 06 Armada

Default

AzNStiImpreza

To answer your above post, SCC actually Shiv and his gang, have a quite a bit of money in there Fwd Project Impreza. Although the motor is internally unmodded they have made a few modifications to there already expensive turbo kit, installed a TEC-II which needed extensive tuning with a laptop (by the way the TEC-II includes 550cc injectors a new coil pack and a bunch of sensors. The TEC-II alone is $2500 and probably a good bit to have installed), a hi flow fuel pump, and a hardened gear set which they destroyed.

Yes they did get nearly 300 hp to the wheels, On Race Gas and on the edge tuning. Not to mention that horsepower is Front Wheel Horspower which will always show much higher numbers due to the elimination of the driveshaft going to the rear diff then beeing split into two axles.

Trust me the limit for a daily driven reliable turboed EJ25 with stock internals is probably somewhere around 300 crank horspower. Good luch breaking your bank for that.

About two weeks ago there was a closed deck legacy motor and 5spd tranny on ebay "Complete" for $1300 plus shipping. Complete = Full motor assembly with AC compressor/Alternator ETC/Turbo/Water to Air Intercooler/Exhaust Manifold/Up-Pipe/Uncut Downpipe/5spd Tranny with front dif in place. Thats a bolt on 230 crank horsepower. The only other item essential for getting this combination to work on a USDM car is the rear diff. Unfortunitely the JDM front diff has a different ratio then the USDM rear diff. Spend $5000 modding this setup with larger fuel pump/Unichip/FMIC/Turbo/Injecters/Catless header/Catless up-pipe/Catless Downpipe/Turbo Back Exhaust/Gauges.
MY99 2.5GT is offline   Reply With Quote
Old 04-05-2002, 05:30 PM   #12
MattC
Scooby Specialist
 
Member#: 158
Join Date: Aug 1999
Chapter/Region: NESIC
Location: CT
Vehicle:
2011 STi
PBP 1999 2.5RS RBP

Default

Although I don't remember if he was on race gas or not, Shiv was most definitely not at the ragged edge of tuning. I really don't think Shiv is ever at the ragged edge of tuning Maybe the fuel system was, as his 550cc RC injectors were just about maxed.

When using a TEC II you are able to do something no other engine management can accomplish. TEC cars can run stinkin rich and still make almost the exact same HP. WHY? Spark duration. The TEC's coils are bar none the best around, and are patented. Setup almost exactly the same as Shiv's car, my car runs as rich as 9.5:1(air fuel ratio); where as any other car is stuck tuning at 12.5:1. Don't believe me? Well dig up a wide band and stick it in mine or efoo's tail pipe. Now you might ask: Why is this good? Well, if I get a bad tank of gas, or a nasty boost spike, the car is more than ready for it. Or what about at track days when the car is being abused lap after lap? Again the TEC has a lot of room for error where as something like a Haltec or stock engine management doesn't. The TEC also has an over boost control which has saved my ass more than once

Between 300-330hp is about as much as you can get out of a reliable EJ25. Unless you have constant access to a higher octane. This is a very rough estimate, that can definitely be debated. Because your motor, MY01 EJ25, has a compression of 10:1 your boost and resultant HP is going to be a bit lower. So, 300 crank HP sounds about right.

I say if your not afraid to learn something new, like TEC engine management, stick with your motor. Shiv(Vishnuperformance.com) makes an amazing turbo kit/TEC II combo. On top of that add fuel rails, a good cat back exhaust, a clutch, a host of gauges, and other odds and ends. Your motor would look a lot like mine. I can asure you that it works. Oh, and no I don't work for Shiv, he just likes to pick on me because I'm young

MattC
MattC is offline   Reply With Quote
Old 04-05-2002, 05:39 PM   #13
MattC
Scooby Specialist
 
Member#: 158
Join Date: Aug 1999
Chapter/Region: NESIC
Location: CT
Vehicle:
2011 STi
PBP 1999 2.5RS RBP

Default

Quote:
Originally posted by MattC
Between 300-330hp is about as much as you can get out of a reliable EJ25. Unless you have constant access to a higher octane. This is a very rough estimate, that can definitely be debated. Because your motor, MY01 EJ25, has a compression of 10:1 your boost and resultant HP is going to be a bit lower. So, 300 crank HP sounds about right.

MattC
I probably should have said a bit more in regards to the HP figures. Trust me thats a lot of HP for these cars. I normally only run 5-7psi on the street. Why? Because it is more than enough to get me into some serious trouble. If you get to this point and don't feel at all satisfied, then there is something wrong with you. By a street bike or something, because you're obviously trying to kill yourself.

On top of that, I really don't recommend building the motor or using a closed deck EJ22. Built motors have many quirks that make them very hard to tune. A built motor is only as good as the person whom made and installed the parts, and really isn't needed unless you have a screw loose in your head The EJ22 doesn't like the EJ25 heads at all. Although they bolt right up, the motor becomes rediculously inefficent above 5k rpms. Shiv was able to run as much as 12psi up to 5krpms, after that it droped down to 5psi by redline. The motor simply wanted to run to hot, EGTs climbed at an alarming rate.

MattC
MattC is offline   Reply With Quote
Old 04-05-2002, 06:32 PM   #14
XT6Wagon
Scooby Specialist
 
Member#: 524
Join Date: Nov 1999
Location: WA
Vehicle:
04 STi
White

Default

MY99 2.5GT, interestingly enough the motor on Ebay runs a 4.111 final drive, so its fine as far as the rear diff for most US non-turbo 5psd cars.
XT6Wagon is offline   Reply With Quote
Old 04-08-2002, 02:37 PM   #15
Dan_E
Scooby Specialist
 
Member#: 673
Join Date: Dec 1999
Chapter/Region: BAIC
Location: Son Josei
Vehicle:
1999 2.5RS-T <RIP>
2000 RS-TURBO'D

Default

$8k and an EJ25 equiped car will get you to 300hp. Reliable and safe. Now whether you like the new body style of the WRX or not is the real question. The new WRX driveline is proven to handle a bit more than this...Maybe just a new clutch. Consider it's heavier and has LESS low end torque than the EJ25.

It comes down to personal preference. I like my agressive GC8 look, and the 2.5 low end grunt. But I am humble amongst the WRX 12 second club. But if I ever get a stronger transmission, you guys are toast
Dan_E is offline   Reply With Quote
Old 04-08-2002, 04:01 PM   #16
MY99 2.5GT
Scooby Specialist
 
Member#: 5030
Join Date: Mar 2001
Chapter/Region: MAIC
Location: Martinsburg, WV, USA
Vehicle:
1999 Legacy 2.5GT
05 Legacy GT 06 Armada

Default

MattC-I really don't doubt that there is more power potential with a built EJ25 compared to a built EJ20. There is no doubt in my mind that added displacement/reworked heads/and a custom designed intake manifold will yield way more power then the same work done to an EJ20.

Simply put its cheaper to swap in a JDM engine as opposed to buying another EJ25 turboing it and buying a TEC-II. Matt don't give me heck about Shiv's near 300 wheel horsepower. I responded to a post with a similar subject a couple months back quoting the information you just did. Shiv himself responded saying that you can't even compare front wheel dyno results to all wheel dyno results. There are too many things that come into play when you eliminate the whole rear drivetrain.

Also taking into account Shiv's reputation for tuning, when I said "on the edge" I meant on the edge of reliability. Sure he could have advanced the timing a little more maybe leaned things out a tiny bit and bumped up the boost but and acheive a little more horspower, but max power on the dyno during one run doesn't mean anything if you blow up your engine or will cause it to die in 5k miles.

I'll pull out the article and read it again tonight.

By the way you said "Between 300-330hp is about as much as you can get out of a reliable EJ25. Unless you have constant access to a higher octane." As stated above. I caught a ride in a 278 wheel horsepower EJ20 WRX with no internal mods and without the complexities of a TEC-II. $5000 was the pricetag. Try spending $5000 on a EJ25 and see what you get. My main concern here isn't what makes the most power in the end because power = $. My concern is what is the greatest power per $ route.

XT6Wagon-Sweet I didn't realize that.
MY99 2.5GT is offline   Reply With Quote
Old 04-09-2002, 06:46 AM   #17
AzNStiImpreza
Scooby Specialist
 
Member#: 17181
Join Date: Apr 2002
Chapter/Region: MAIC
Location: "fredneck", Maryland
Vehicle:
2013 Scion FRS
Whiteout

Default money ay?

if i had a buttload of money, i would spend it hooking up an ej25 just to see wut happeneds. I bet with proper tuning using all the good parts can get the ej25 over 400 hp. I dun get how the ej20 and ej25 are so far apart. i bet, if subaru was to use there ej25 and did a little tweaking here and there it will be a bad ass engine. but n e way, im not some jock about engines and all but shouldnt 2.5liters be better than 2.0 liters. Is there any possiblity where u could build like a hybrid engine the way Honda engines are built, combining two engines and stuff? that will be the hot shizzle.
AzNStiImpreza is offline   Reply With Quote
Old 04-09-2002, 08:04 AM   #18
XT6Wagon
Scooby Specialist
 
Member#: 524
Join Date: Nov 1999
Location: WA
Vehicle:
04 STi
White

Default

Well To voice my opinion, lets say a japanese EJ-20T is going into my car. Its dirt cheap to do in comparison to the turbo kit deal, because I'll get to sell off lots of parts both from my car and what I don't need out of the "box of goodies" to defray the costs. If you already have a EJ-25 you might want to slap all the Turbo junk on it, then sell the old longblock to someone who is a closed deck Nazi.

Then is the "cheap" mods like a full exaust, 50 shot, Water/Air IC, crank pulley, etc.

After that I think it will be time for a Phase II EJ-25 block with some late model DOHC solid lifter heads. To me it seems like the EJ-25 is a "cheap" upgrade as the solid lifter heads can make alot more power than the early hydo heads, Its cheap to raise the redline to 8K and the extra displacement raises the AVG HP through the powerband, and makes daily driving much better.
XT6Wagon 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
WTT/FS 2008 Subaru Legacy 2.5i Ltd for 2000-2001 2.5rs + Cash or 2002-2003 WRX + Cash CCSubaru Private Vehicle 'For Sale' Classifieds 2 04-24-2010 08:45 PM
Project Rally RS - 2001 2.5RS into Stage Rally Car 409Industries Member's Car Gallery 16 01-14-2009 02:04 PM
Possible for sale local. 2001 2.5rs nukem2.5rs North West Impreza Club Forum -- NWIC 12 04-23-2004 09:53 PM
turbo kit for the 2001 2.5RS Bluee Normally Aspirated with bolt-on Forced Induction Powertrain 6 10-05-2003 04:11 AM
My 2001 2.5RS Turbo Project-----Advise welcome redmeanie Normally Aspirated with bolt-on Forced Induction Powertrain 2 03-10-2002 03:19 AM


All times are GMT -4. The time now is 01:20 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.