Welcome to the North American Subaru Impreza Owners Club Sunday March 1, 2015
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 12-05-2002, 11:54 AM   #1
mykrrrr
Scooby Guru
 
Member#: 733
Join Date: Jan 2000
Chapter/Region: MWSOC
Location: Squadra Delle Pecore Nere
Vehicle:
'13 Focus ST

Question WRX Motor Swap w/2.5RS drivetrain Question.

I know that it's possible to do a motor swap and retain the stock USDM 2.5 RS drivetrain but what are the advantages/disadvantages of going this route???

Here's what I'm assuming so far:

Advantage(s)
Retain stock driveline
"Ease" of swap.
Reduced cost of swap

Disadvantages
???

Anyone have other opinions on this swap route???

-mykr.
* Registered users of the site do not see these ads.
mykrrrr is offline   Reply With Quote
Old 12-05-2002, 02:10 PM   #2
Aspen
Scooby Specialist
 
Member#: 145
Join Date: Aug 1999
Chapter/Region: MWSOC
Location: The Windy City
Vehicle:
Banned to
Housework for Summer

Default

Mike,

You will see all the advantages soon...
Aspen is offline   Reply With Quote
Old 12-05-2002, 02:16 PM   #3
mrbell
Scooby Specialist
 
Member#: 1871
Join Date: Jul 2000
Location: Salt Lake City, UT
Vehicle:
2000 Impreza 2.5RS
Blue Ridge Pearl

Default

Well, theoretically the low gearing of the RS will improve accelleration, but hurt your top end. I don't particularly care about going 150mph(or whatever the top speed of a WRX may be), but getting out of the hole faster is what I want. The problem is that the spacing may not be optimized for the WRX powerband. Since they're so close together, you may end up shifting above the optimal point. Then again, it could be better, I don't feel like doing math today :-D
mrbell is offline   Reply With Quote
Old 12-05-2002, 02:26 PM   #4
mykrrrr
Scooby Guru
 
Member#: 733
Join Date: Jan 2000
Chapter/Region: MWSOC
Location: Squadra Delle Pecore Nere
Vehicle:
'13 Focus ST

Arrow

David - You gonna be around tonight for the Denny's meet??? We can talk about it then.

mrbell - when you get time, please explain more.

-mykr.
mykrrrr is offline   Reply With Quote
Old 12-05-2002, 03:49 PM   #5
Craig W
Scooby Specialist
 
Member#: 643
Join Date: Dec 1999
Chapter/Region: BAIC
Location: Redwood City, CA, USA
Vehicle:
1999 2.5RS
WRX powered

Default

Check out i-speedusa.com. They specialize in the WRX swap and you can pm skywalker or christoph1371 here on the NASIOC.
Craig W is offline   Reply With Quote
Old 12-05-2002, 06:25 PM   #6
Bankheist
Scooby Guru
 
Member#: 2237
Join Date: Aug 2000
Chapter/Region: TXIC
Location: DFW
Vehicle:
2000 GC8 STi
2015 Ford Mustang GT

Default

bolts up fine perfectly... dont worry about it

you will need the ECU (or a stand alone)and wiring harness and a WRX/Legacy turbo crossmember.
Bankheist is offline   Reply With Quote
Old 12-05-2002, 11:20 PM   #7
EddyRS
Scooby Specialist
 
Member#: 1257
Join Date: Apr 2000
Location: In the Valley.....Somewhere...
Vehicle:
2000 GC8 WRX
93 RS-W Wagon (White) RIP

Default

I have the exact comb (WRX motor with RS Tranny-back) The car pulls hard in all gears. True you loose a little on 5th, but gain so much throughout the normal driving range of the car.

Personally I don't care driving fast in a straight line, my fun comes with driving in very twisty roads where the close-course gearing of the RS allows the WRX motor to really shine.

Also remember the STi's in Japan all have 4.111 and 4.444 final drives and really close ratio gearing. Just something to consider.

Cheers

EddyL.
EddyRS is offline   Reply With Quote
Old 12-06-2002, 08:15 AM   #8
mykrrrr
Scooby Guru
 
Member#: 733
Join Date: Jan 2000
Chapter/Region: MWSOC
Location: Squadra Delle Pecore Nere
Vehicle:
'13 Focus ST

Default

Eddy - So yer saying there's no real disadvantages to it. What's the final drive of a stock RS and WRX??? I too am not looking for peak absolute power and being able to claim my car can go 170 mph. I want something I can drive on a daily basis without having to worry about reliability and something that's fun @ the rallyX or whatever.

Keep the discussion going fellas!!!

-mykr.
mykrrrr is offline   Reply With Quote
Old 12-06-2002, 11:42 AM   #9
mykrrrr
Scooby Guru
 
Member#: 733
Join Date: Jan 2000
Chapter/Region: MWSOC
Location: Squadra Delle Pecore Nere
Vehicle:
'13 Focus ST

Question

Here's another question on the motor only swap...

The WRX uses a pull type clutch and the RS uses a push type clutch (so I'm told.) What clutch would this hybrid use???

-mykr.
mykrrrr is offline   Reply With Quote
Old 12-06-2002, 12:53 PM   #10
Aspen
Scooby Specialist
 
Member#: 145
Join Date: Aug 1999
Chapter/Region: MWSOC
Location: The Windy City
Vehicle:
Banned to
Housework for Summer

Default

You use the same type of clutch with the transmission that you are going to use. If you plan on using your existing RS tranny, then it would be a push type clutch.

RS fd=4.11
WRX fd= 3.9
Aspen is offline   Reply With Quote
Old 12-06-2002, 03:36 PM   #11
snwbrder206
Scooby Newbie
 
Member#: 9817
Join Date: Aug 2001
Chapter/Region: NWIC
Location: Seattle, WA
Vehicle:
1995 ImprezaJDM EJ20
2007 Forester XT CGM

Default hmmm....

Well this idea has just sparked a ton of questions. Has anyone else done this swap? How is it compared to total WRX drivetrain swap vs turbo RS vs WRX engine/RS trans swap? Sorry to kind of hijack this thread. Well I am just wondering the basics... cost, reliabilty, problems had/have/will have...anything else I should know. Thanks so much... peace ~Erick
snwbrder206 is offline   Reply With Quote
Old 12-06-2002, 06:27 PM   #12
RebelINS
Scooby Specialist
 
Member#: 2953
Join Date: Nov 2000
Chapter/Region: MWSOC
Location: Rochester, MI, USA
Vehicle:
2000 Impreza 2.5RS
2005 Impreza WRX STi

Default

Quote:
Also remember the STi's in Japan all have 4.111 and 4.444 final drives and really close ratio gearing. Just something to consider.
Actually, the RS gears are closer then the STi. I used to think the STi gears where closer as well, but then I calculated it, and found out that they aren't.

-Wes
RebelINS is offline   Reply With Quote
Old 12-06-2002, 06:42 PM   #13
mykrrrr
Scooby Guru
 
Member#: 733
Join Date: Jan 2000
Chapter/Region: MWSOC
Location: Squadra Delle Pecore Nere
Vehicle:
'13 Focus ST

Default

Erick - Here's my take on your questions:

Reliability - If obtained though a reputable dealer, the motor should be fine. IMO, it'll be a bit more stout that a 2.5 w/a turbo since the motor was designed for boost from the get go.

Cost - I've been talking to a reputable Subaru shop and it's about the same as a Ludespeed stage II w/a stand alone EMS. It might actually be a bit cheaper if I went w/a stock WRX ecu.

Problems - ??? That's a main thing I wanted clarified in my posting this.

-mykr.
mykrrrr is offline   Reply With Quote
Old 12-06-2002, 08:36 PM   #14
ImprezaRSX
*** Banned ***
 
Member#: 10955
Join Date: Oct 2001
Chapter/Region: NWIC
Location: Lake Stevens, WA
Vehicle:
07, 06,01,93 I have
4 domtuned subys

Default

Problems with using the RS tranny:
Excessive G-Forces on launch can cause wrinkles on the back of your clothes.
148MPH top speed (approx) can get you tickets
Optimum gears for SoloII might help you win.
Excessive tire wear from taking the long way home.
Pissin' off other WRX owners with faster 60' times

The only real problem I can think of...

























uh... yeah... HAVE FUN MAN!
ImprezaRSX is offline   Reply With Quote
Old 12-06-2002, 11:51 PM   #15
Rentankonko
Scooby Newbie
 
Member#: 15903
Join Date: Mar 2002
Location: Chicago
Default

Ahhhh, this is just the issue i've been pondering. The first thing I would try to do is find out if there is any significant strength differences between the two transmissions. I also agree that the closer gear ratio seems more desirable from a drivability standpoint. someone mentioned that the RS has a shorter overall drive ratio than the STI, what about the STI RA? Finally, given the extra 1500 or so RPM that the EJ20T would give us, could 60+ mph be reached in 2nd gear?
Rentankonko is offline   Reply With Quote
Old 12-07-2002, 12:08 AM   #16
ImprezaRSX
*** Banned ***
 
Member#: 10955
Join Date: Oct 2001
Chapter/Region: NWIC
Location: Lake Stevens, WA
Vehicle:
07, 06,01,93 I have
4 domtuned subys

Default

probably real close...
ImprezaRSX is offline   Reply With Quote
Old 12-07-2002, 01:18 AM   #17
RebelINS
Scooby Specialist
 
Member#: 2953
Join Date: Nov 2000
Chapter/Region: MWSOC
Location: Rochester, MI, USA
Vehicle:
2000 Impreza 2.5RS
2005 Impreza WRX STi

Default

You wouldn't quite be able to hit 60. You would be at redline at 58.1! You would need to up the redline a tad to hit 60. Se this thread below, where I calculated and compared the RS and STi ratios.

http://forums.nasioc.com/forums/show...hreadid=268952

-Wes
RebelINS is offline   Reply With Quote
Old 12-08-2002, 01:20 AM   #18
AdamSTi
Scooby Specialist
 
Member#: 562
Join Date: Nov 1999
Chapter/Region: Tri-State
Location: NJ
Vehicle:
07Tr 06 XRunner
02 25RS

Default

Why wouldn't you be able to hit 60mph? The WRX's redline is 7K something, unlike the 6250 the RS's have.
AdamSTi is offline   Reply With Quote
Old 12-08-2002, 02:31 AM   #19
ImprezaRSX
*** Banned ***
 
Member#: 10955
Join Date: Oct 2001
Chapter/Region: NWIC
Location: Lake Stevens, WA
Vehicle:
07, 06,01,93 I have
4 domtuned subys

Default

Rebel already calculated the top speed with the higher redline.
RS's CAN'T do 58 in second gear.
ImprezaRSX is offline   Reply With Quote
Old 12-08-2002, 02:38 AM   #20
RebelINS
Scooby Specialist
 
Member#: 2953
Join Date: Nov 2000
Chapter/Region: MWSOC
Location: Rochester, MI, USA
Vehicle:
2000 Impreza 2.5RS
2005 Impreza WRX STi

Default

ImprezaRSX is correct, when I posted before I had calculated it with a 7K redline, which is what the WRX has. In an RS, you can only hit roughly 51.875 in 2nd. If you had a WRX engine with a redline of 7250, with an RS trans, you could hit sixty in second.

-Wes
RebelINS is offline   Reply With Quote
Old 12-08-2002, 08:44 AM   #21
AdamSTi
Scooby Specialist
 
Member#: 562
Join Date: Nov 1999
Chapter/Region: Tri-State
Location: NJ
Vehicle:
07Tr 06 XRunner
02 25RS

Default

I know you can't hit 60 in an RS, I have one. I was saying you can hit 60 with an EJ20/RS combo.
AdamSTi is offline   Reply With Quote
Old 12-08-2002, 03:22 PM   #22
ImprezaRSX
*** Banned ***
 
Member#: 10955
Join Date: Oct 2001
Chapter/Region: NWIC
Location: Lake Stevens, WA
Vehicle:
07, 06,01,93 I have
4 domtuned subys

Default

Ok ADAM you're missing this again.

7k redline in WRX, in second gear is 58MPH
IF you up the redline to 7250 you just barely hit 60MPH.

Second gear COULD go up to 60 if you MODIFY the ECU setpoints.
Same thing for an RS, if I MODIFIED the ECU I COULD go 60 in second.
ImprezaRSX is offline   Reply With Quote
Old 12-09-2002, 12:13 AM   #23
EddyRS
Scooby Specialist
 
Member#: 1257
Join Date: Apr 2000
Location: In the Valley.....Somewhere...
Vehicle:
2000 GC8 WRX
93 RS-W Wagon (White) RIP

Default

I hit 58.3 mph in second gear right at 7000rpm in my configuration. (WRX motor, Stock ECU, RS Tranny) The extra 750 rpm give me a little more but not enough. Also it gets there VERY fast.

Oh....the only drawback with a RS tranny.....You hit redline way too soon. It pulls so hard all the way to redline that you don't know that you are there until the ECU causes fuel-cut. Power feels so linear, there is no peaking off at the hi rpms, I feel that it could pull another 500rpms before I felt power taper out. I kind of wish I had a STi's 8000 rpm. I take that back.....I do wish.

All in all I love this configuration. It feels as it should be this way from the factory.

Cheers

EddyL.
EddyRS is offline   Reply With Quote
Old 12-09-2002, 03:57 AM   #24
mykrrrr
Scooby Guru
 
Member#: 733
Join Date: Jan 2000
Chapter/Region: MWSOC
Location: Squadra Delle Pecore Nere
Vehicle:
'13 Focus ST

Talking

EddyRS is doing the right thing and moving the debate of if a RS trannied WRX can hit 60 in 2nd back to the original questions. I say who really cares if it can hit 60 in 2nd gear...let's talk about the motor swap.

-mykr.
mykrrrr is offline   Reply With Quote
Old 12-09-2002, 06:15 PM   #25
geronimo66
Scooby Specialist
 
Member#: 26929
Join Date: Oct 2002
Location: Macomb Twp. MI
Vehicle:
2000 Impreza
with Gremilins

Default

yea, I would like to here more from people who have had it done. I was looking at a WRX, but I need a new house more than a 25k car. So now I am thinking wither an RS or L, and a swap from Lachute in CND. I and thinking that the L might be a better way to go. Less money up front.

Anyone here dealt with Lachute? I am going to give them a call soon, prior to buying a car. I want their input.

Thanks,

Anyone want a nice use LandRover!!! help my "L-WRX" project
geronimo66 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
2005 2.5rs To Wrx Motor Swap 05SUBY2.5RS Subaru Conversions 7 03-09-2006 02:52 PM
WRX motor swap into 2001 2.5RS RyansJDMgc8 Subaru Conversions 5 05-17-2005 03:18 AM
can anyone here wire a wrx motor into a 2.5rs? sc00bywagon Private 'Wanted' Classifieds 0 05-02-2005 11:45 PM
Newb 2.5rs drivetrain questions. Clutch, LSD, Diffs... cwb124 Transmission (AT/MT) & Driveline 2 12-07-2003 07:55 PM
2002 wrx engine swap with 2.5RS? huey Normally Aspirated Powertrain 8 01-30-2001 01:23 AM


All times are GMT -4. The time now is 07:16 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2015 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.