Head ports comparison

Discussion in 'Modifications And Maintenance' started by FuJi K, Dec 18, 2005.

  1. FuJi K
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    FuJi K Well-Known Member

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    Here are pics of different heads from USDM to JDM variations old skool and new skool.

    The MUCH TALKED about BIGport and SMALLport port runner casting style found in USDM/EURO/AUS WRX STi's
    bigport
    [​IMG]
    smallport
    [​IMG]


    USDM WRX/STi/STI/FXT/LGT turbo models as of current PHASE 2 head
    [​IMG][​IMG]

    JDM STi PHASE 2 head
    [​IMG][​IMG]

    USDM 2.5L 2.2L Phase 2 NA head
    [​IMG]

    Old SKOOL JDM WRX/STi head
    Early variation
    [​IMG]

    Later variation
    [​IMG][​IMG]

    USDM '96 2.5L DOHC NA head PHASE 1 HLA valvetrain
    [​IMG][​IMG]

    USDM '97-99 2.5L DOHC NA head PHASE 1 shim overbucket valetrain
    [​IMG][​IMG][​IMG]

    HEAD CAMPARO
    JDM Ver6 and Ver5
    [​IMG]

    '97-'99 2.5L DOHC NA head Phase1 on top of PORTED USDM '03 WRX head
    [​IMG]

    JDM STi PHASE 2 head on top of '97-'99 DOHC 2.5L NA head overlayed with '96 2.5L DOHC NA head
    [​IMG]

    JDM STi PHASE 2 head on top of '97-'99 2.5L DOHC NA head
    [​IMG]

    USDM WRX head PHASE 2 on top of '97-'99 2.5L DOHC NA HEAD
    [​IMG]

    head tech talk
    http://forums.nasioc.com/forums/showthread.php?t=424055&highlight=springs+sohc
     
  2. AWDimprezaL
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    AWDimprezaL has more posts than you

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    look at the dohc N/A heads...bleh
     
  3. FuJi K
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    FuJi K Well-Known Member

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    The NA DOHC 2.5L ports look a lot like the STi Ver V RA ports. The spiltter is skinny. Looks way better than the USDM WRX ports. I'd like to see the ports on the 93-97 Type R/RA heads.
     
  4. Dynapar
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    Dynapar Well-Known Member

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    did the type Rs have different engine components? i have heard mixed results on this. some say that the type Rs were slightly different in teh engien area, and i dont know what part.
     
  5. kickin_81
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    kickin_81 Well-Known Member

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    They all look the same to me... and so does everyone here.
     
  6. CBR04WRX
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    CBR04WRX Well-Known Member

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    Look at all the material that you can remove on the US WRX heads! Has anyone here port matched the intake side of their cylinder heads? Any gains/losses?
     
  7. FuJi K
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    FuJi K Well-Known Member

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    humm....you'd have to port a good amount on the WRX heads......
    so to speak, soem heads come from factory with eeWwWWW castings...which you can improve. Some heads come from factory looking fine. Our Subaru heads, well it depends on which casting...like...yoru WRX heads, or JDM STi Ver 7 head/phase1 2.5L NA head.

    there was some comparison last night at Firestone....it cleared up a lot of questions....
     
  8. wall of tvs
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    wall of tvs Well-Known Member

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    One of them is getting the shocker, hehehehe.
     
  9. Dynapar
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    Dynapar Well-Known Member

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    what did your comapison yield? to me those V6 type R heads look the best. maybe its cause they are shiny.
     
  10. FuJi K
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    FuJi K Well-Known Member

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    well....Matt brought out a JDM Ver7 head....
    I looked at it...and I was like...ey it looks just like mine. I put my 2 fingers in the port and mine...they where VERY identicle. We compared valve size...they wherethe SAME size. The only difference we noticed was at the injector boss....the JDM Ver 7 was a bit wider.....some porting on the 2.5LNA heads will make it larger as well.

    SO what I'm guessing is that Subaru used the SAME intake bolt pattern, but used the SPECIAL casting they use for the TypeRA/TypeR/STi for the port. Because the 2.5LNA head for the Subarus in the US runs from 96-99. This is my best guess.

    Some of the pictures of the ports where taken at a different angle...so it does show that they look a little different. I love my heads now! I was going to give up at one point.....until I keep researching and viewing the pics.
     
  11. FuJi K
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    FuJi K Well-Known Member

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    TTT

    so.....guys at NASIOC are not believing what I'm trying to get at.... "the intake runner to the valve" so...oh well...whatever....
    SO!~!!

    who want to do a CC on the heads they have? Lue (LVT) has his motor take apart right now SO we have a SOHC 2.5L head in the play as well. I'm going t ogo to X-MAN over near Firestone to pick up a tube thingy that Russ and Matt was talking about....then...we shall do some CCing....

    Where should we do this CC?

    EDIT:..... I'll take a pic of my heads again at the SAME ANGLE as a pic of their "big port" heads.... then we can see. But really...seeing them in person is best.
     
  12. FuJi K
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    FuJi K Well-Known Member

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    LETS FEED THE FIRE!!
    A BIG PORT HEAD, or so they say....
    [​IMG]

    humm....I dunno.... I like my 20/20 vision.....
    lets feed the fire!

    Here are some WRX heads with my 2.5NA DOHC. yes, you can SEE the big difference....yes I can too (with no glasses).
    [​IMG]

    Here's the Ver7..or maybe Ver8 because it's some RHT20 # thingy oh its....
    ...and ya my 2.5L DOHC on the bottem.....
    [​IMG]

    Few more just so you can see it better.....
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
  13. FuJi K
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    FuJi K Well-Known Member

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    NOW HERE IS WHERE I GO INTO SOME DETAIL.

    of course, the different combustion chamber...but top view at "this" angle
    [​IMG]

    NOW with the SAME WATER BOTTLE CAP.
    STi 7 head TOP, 2.5L DOHC bottem
    [​IMG]
    [​IMG]

    [​IMG]
    [​IMG]

    [​IMG]
    [​IMG]

    SO WHAT's the BIG DIFFERENCE?
     
  14. FuJi K
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    FuJi K Well-Known Member

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    OKIES, something NEW.... I got to take a look at the FIRST DOHC NA 2.5L that we got here in the US. This head is the hydraic style valvetrain. A '96 2.5L. I NOTICED that the port is the SAME SHAPE as the gasket. The 4mm LOST is not apparent on this head. The valve covers are stamped with "4 CAM 16 VALVE" on the sides. The valve guides look just like mine so this port is actually a bit different from the SVX port, which I've seen is the same port casting on the OLD STi EJ20G heads, not sure of the Legacy EJ20G but the Imprezas seem to be. NOTE: The engine is from a friend of mines (wagonL) and is out of a '96 Legacy 2.5GT. He somewhat touched the splitters so I'm not sure if it was skinny like the '98 or what.

    Here is a pic. NOW we have a '96 DOHC 2.5L head in the bunch. Not sure of the Combustion chamber yet. No doubt these '96 EJ25NA heads are KING here as a US-Spec Subaru head for intake port.
    [​IMG]
    [​IMG]

    Here its layered on top of my '98 EJ25NA head to compare with the BIG PORT STi head on top.
    '96 head LAYERED over the botten head which is a '98.
    [​IMG]

    Here you can see the Valve guide how it protudes into the port MORE than the DOHC EJ25NA head.
    EJ20G
    [​IMG]

    '96 EJ25 NA DOHC
    [​IMG]
     
  15. Musashi
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    Musashi Well-Known Member

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    Great job, the difference is very clear! Now when will we get to see the results?
     
  16. FuJi K
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    FuJi K Well-Known Member

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    Here are a few pics of a freshly aquired '96 2.5L DOHC from a '96 USDM Legacy Outback. Noticed how much BIGGER the combustion chamber is. This has the LARGE intake ports w/ matching intake manifold and is HLA. The OLDER model HLA where a little different.

    I'll get some pics of the set of heads in the near future; EJ22T, '97-'99 EJ25D, '96 EJ25D, EJ205 USDM, EJ207 JDM.

    But here are the pics of the '96 2.5L DOHC.
    [​IMG][​IMG][​IMG][​IMG][​IMG]
    [​IMG][​IMG][​IMG][​IMG][​IMG]

    This is the matching PISTONS that came on this '96 motor. All the '97-'99 runs different pistons.
    [​IMG]
     
  17. piddster
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    piddster Lone Wolf

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    Fuji, IIRC, '99 went to the SOHC design.
     
  18. FuJi K
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    FuJi K Well-Known Member

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    The Legacy Outbacks still used the DOHC. Impreza and Foresters went SOHC.
    In general I say 97-99. If Impreza 2.5RS only then '98.
     
  19. FuJi K
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    FuJi K Well-Known Member

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    I was VERY VERY curious if the '06 WRX heads would work with my EJ22T setup. So I HAD to get that '06 WRX head off over at my friend's house. With and hour or so we got the head off because we couldn't get the exhaust cam gear off. The back timing belt cover broke when the car got into a slight frontal collision so we just finished it off and got the exhaust cam off after the AVCS bracket came off.

    I brought over my EJ22 HG just to measure. The EJ257 heads are a it wee wide, 99mm or so and my EJ22 HG wasn't wide enough in between the combustion chambers. On the '06 WRX heads, they worked out JUST FINE!!!!! I am a happy camper!!!! The combustion chamber however is a lot different from the EJ257 and EJ205. Its sides are ROUND.

    EJ257 ('04 STi), EJ205 ('02-'03 WRX), EJ255 ('06 WRX)
    [​IMG][​IMG][​IMG]

    Next I looked at how thick the heads where for porting purposes. This is so I know how WIDE I can go, how much lower I can go on the short side, and the HIGH side of the intake port. The EJ205 heads have the thickest casting. You can go WIDER, and taller, and also lower on the intake ports. If you had a CNC machine, you could make them a direct replica of the JDM Big Ports. Had porting what you want to do is widen the ports down, skinny up the splitter, and make it D shape if you're like me, or just make the O's runners bigger.
    [​IMG][​IMG]
    [​IMG][​IMG]
    [​IMG][​IMG]
     
  20. FuJi K
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    FuJi K Well-Known Member

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    CELL PHONE PIC, mind you..... LG Dare 3.2megpix hA!


    What's also interesting is how much LOWER you can go with the short side at the entry. The EJ205 heads allow you to and is the same as the JDM big port heads on this side. The EJ257 heads this side is NOT thick, the EJ255 heads it has a little nub/stub that comes out which gives you some room. The JDM Big ports isn't that much lower at the entry, so you don't have to go LOW on this side at the entry. The STi heads I'm porting at the moment I am NOT going that low and especially at the splitter you don't want to because you might port through the head.
    [​IMG][​IMG][​IMG][​IMG]

    Another NEW thing is the HEAD GASKET layout with the coolant paaseges. They FINALLY revised the HG. This is NOT apparent on the '04-'05 STi heads, unsure about '06+. Also notice the head coolant passages are different too. You MAY have issues running this with a OEM CLOSED DECK EJ22T. However, you might get away with an aftermarket CNC billet closed deck brace from OutFrontMotorsports. The HG is still the same 3layer thickness. Coolant still feeds bottom up.
    [​IMG][​IMG][​IMG]
     
  21. FuJi K
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    FuJi K Well-Known Member

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    '04 STi heads I'm working on at the moment.

    [​IMG][​IMG]
    [​IMG][​IMG]
     
  22. Musashi
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    Musashi Well-Known Member

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    Great job, they look awsome. Can't wait to see what they can do.
     
  23. vangstaboi86
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    vangstaboi86 Well-Known Member

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    yeah fuji, can't wait ;p
     
  24. FuJi K
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    FuJi K Well-Known Member

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    STi Version 6 heads VIDEO
     
  25. KSAL
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    KSAL Well-Known Member

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    FUJI.....u da man!! thanks for all that info
     
  26. Musashi
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    Musashi Well-Known Member

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    Just finished watching the video you submitted and I think it's appropriate we should start calling you Dr. JDM DD!!! Great job with the physical exam there doctor!
     
  27. FuJi K
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    FuJi K Well-Known Member

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    JDM STi Version 6 head port gallery

    [​IMG][​IMG][​IMG][​IMG]
    [​IMG][​IMG][​IMG][​IMG]
    [​IMG][​IMG][​IMG][​IMG]
     
  28. FuJi K
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    FuJi K Well-Known Member

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    '06 WRX heads stock
    [​IMG][​IMG][​IMG]

    '04 STi heads getting a port job.
    [​IMG][​IMG][​IMG][​IMG]
    [​IMG][​IMG][​IMG][​IMG]

    '03 WRX heads ported intake

    [​IMG][​IMG]
     
  29. FuJi K
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    FuJi K Well-Known Member

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    PAY CLOSE ATTENTION.
    No one else will show you this. Dog leg of the '04 STi and '02 WRX heads.

    EJ257 STi (slightly ported) ........... EJ205 WRX (STOCK)
    [​IMG][​IMG]
     
  30. FuJi K
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    FuJi K Well-Known Member

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