STI bottom end in WRX??
+ Reply to Thread
Results 1 to 15 of 15

This is a discussion on STI bottom end in WRX?? within the Builds forums, part of the Tech & Modifying & General Repairs category; Due to a broken WRX engine i am thinking about doing the STI bottom end with my WRX heads Everthing ...

  1. #1
    Registered User
    Join Date
    Dec 2011
    Posts
    16

    STI bottom end in WRX??

    Due to a broken WRX engine i am thinking about doing the STI bottom end with my WRX heads Everthing i am seeing is saying the STI bottom end is a direct swap. I need a new oil pump pick up timing belt set. Is this stuff the same for the WRX & STI?? also will the header i have of my 2.0 now fit with the STI bottom end or is the STI block wider and i now need new header?? Same with the intake?? Will my stock WRX one fit or do i now need an STI one?? If anyone had done this swap any info or help would be great THANK

  2. Remove Advertisements
    ClubWRX.net
    Advertisements
     

  3. #2
    Moderator T0rque's Avatar
    Join Date
    Dec 2004
    Location
    Medford, Oregon
    Posts
    25,522
    I Support ClubWRX
    Ok.. So yes the STi swap is a direct fit. You will need the Wrx oil pan or a different oil pan. Everything else will work just fine. You will need to be re-tuned however.


    Lead Wrench @ WTF Tuning, LLC

  4. #3
    Registered User poly_poly-man's Avatar
    Join Date
    Feb 2010
    Location
    Rochester Institvte of Technorcery
    Posts
    1,223
    Everything will bolt right on.

    HOWEVER, two issues arise. First off, your compression ratio rises, and that's not necessarily good. Best to ask your tuner what he suggests, but it likely will involve thicker headgaskets, or perhaps some machining. Secondly, you NEED a tune. You will NOT be okay temporarily without one. Talk to a tuner BEFORE the build to help you out.
    My big thread: The Used WRX Buying Checklist - Please Contribute!

    My current car: 2002 WRB WRX Wagon.
    Mods: GM BCS, Carberry SD rom, uppipe, AEM UEGO, Klunk Killer, F+R shifter bushings, head unit

  5. #4
    Moderator T0rque's Avatar
    Join Date
    Dec 2004
    Location
    Medford, Oregon
    Posts
    25,522
    I Support ClubWRX
    That's only one issue.. Compression is different resulting in needing a new tune.


    Lead Wrench @ WTF Tuning, LLC

  6. #5
    Registered User
    Join Date
    Dec 2011
    Posts
    16
    the car already has a tune in it now for the mods that are already done. I already have 850cc injectors and a 255pump. while the heads are off i was prob going to change the cams also. So it will deff need retuned. A raise in compression is prob not going to be good runnig 20lbs of boos now. The closest AWD dyno and tuner that i trust is about 2hours away so it will deff need to be towed. Am i good with just a start up to make sure everything is ok??

  7. #6
    Moderator T0rque's Avatar
    Join Date
    Dec 2004
    Location
    Medford, Oregon
    Posts
    25,522
    I Support ClubWRX
    your tuner should be able to set you up with a base map so you can load it on to the car with a tactrix or cobb ap and run that thru its break in.. Honestly a 2.5 bottom end is a good start but if you build the 2.0 or do a 2.2 your gonna be just as good in the end. if not better being more reliable with a built motor.. STi bottom ends have a slightly better piston but still not amazing..


    Lead Wrench @ WTF Tuning, LLC

  8. #7
    Registered User
    Join Date
    Dec 2011
    Posts
    16
    That's what I was not sure about building my 2.0 too a 2.2 or putting a STI 2.5 in it. I hear pusses and
    Minus both ways. This is not a race car this is my DD car it will drive in Ohio snow and prob see 15k-20k miles a year. When I got the car it already had a Perrin front mount inveden downpipe FP green turbo 850cc injectors. I
    Just want to use what came on the car to its potential yet keep myself from
    Blowing up the motor.

  9. #8
    Moderator T0rque's Avatar
    Join Date
    Dec 2004
    Location
    Medford, Oregon
    Posts
    25,522
    I Support ClubWRX
    Build the bottom end. Unless you want to keep going thru oem short blocks.


    Lead Wrench @ WTF Tuning, LLC

  10. #9
    Registered User
    Join Date
    Dec 2011
    Posts
    16
    i was thinking about a 93mm bore 70mm stroke that should put me at about 2.15L and staying around 8.3-8.5 compression. Arp head studs. Is stock subi bearing good or should i go aftermarket. I am also looking at the crower 222/400 stage 2 cams. It would be sweet if i got this thing up to about 400WHP!!

  11. #10
    The Default One SeattleJeremy's Avatar
    Join Date
    Jul 2004
    Location
    Seattle, WA
    Posts
    4,488
    Quote Originally Posted by SubiNubee View Post
    It would be sweet if i got this thing up to about 400WHP!!
    400WHP in a car that was designed with 180-200WHP in mind is difficult to maintain. Please read this thread Link

  12. #11
    Registered User
    Join Date
    Dec 2011
    Posts
    16
    based on the 400Hp post i have about 90% of that stuff. my car hit 320whp with 22lbs of boost this summer.MY goal is to make this car just as fast as my LS1 car which does 480WHP. I dont mind falling short of the 400mark. There is plenty of EVO's in my area that is at the 350-400 mark and i would love to run with a few of them out of a WRX not a STI

  13. #12
    Registered User Pylonpounder's Avatar
    Join Date
    Aug 2010
    Location
    Factoryville, PA
    Posts
    380
    For that much power? I'd definitely build the bottom end even if you use the 2.5. Plus 2.5 headgaskets ARP headstuds, CNC work to the heads, and expect it to blow up sooner or later.

  14. #13
    Registered User
    Join Date
    Dec 2011
    Posts
    16
    i am leaning to doing STI bottom end with new pistons and total seal gapless rings. I already have arp head studs in a box for the build. I just need to know of a good head gasket. I have cometic on my LS1 but i have heard a few not so good things about them on the SUBARU engines?

  15. #14
    Registered User Pylonpounder's Avatar
    Join Date
    Aug 2010
    Location
    Factoryville, PA
    Posts
    380
    There's so many things to go wrong with a subaru engine, I used cometic and haven't had an issue but that's not to say others won't. The best way to not rebuild a scoob every year is to leave it stock.

  16. #15
    Registered User
    Join Date
    Dec 2011
    Posts
    16
    i got the car from a dealer and it already was not stock.

+ Reply to Thread

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself. We strongly suggest that you stay away from using aol, yahoo, msn, and hotmail accounts. Sometimes the mail server blocks the emails from our server. As a result you will not receive any notifications including the confirmation email.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •