1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Port Matching

Discussion in 'General Tech and Maintenance' started by swanny, Sep 17, 2003.

  1. swanny

    swanny Senior Member

    Messages:
    3,779
    Likes Received:
    1
    Joined:
    Jul 13, 2003
    Location:
    buck teeth and government checks, PA
    I just picked up a stainless OBX 4-2-1 header for my 95 GSR and I was wondering if anyone had experience port matching. Any advise or specs on what it should be bored to? Thanks
     
  2. JDMilan

    JDMilan Senior Member

    Messages:
    6,730
    Likes Received:
    0
    Joined:
    May 11, 2003
    Location:
    Boca Raton, FL
    Well usually people take some of the extra welding out of the jdm ITR 4-1 header since there is welding that can be taken off, chances are your header is flush with no extra welding.
     
  3. swanny

    swanny Senior Member

    Messages:
    3,779
    Likes Received:
    1
    Joined:
    Jul 13, 2003
    Location:
    buck teeth and government checks, PA
    im refering to the flange that bolts to the head. the ports on the flange are not the same diameter of the tubing on the exhaust, there smaller. so i figure boring those out to the width of the tubing would increase flow.
     
  4. JDMilan

    JDMilan Senior Member

    Messages:
    6,730
    Likes Received:
    0
    Joined:
    May 11, 2003
    Location:
    Boca Raton, FL
    you could open it up a little, but gains are going to be literally nothing, so really it's not worth the time, and bits..
     
  5. swanny

    swanny Senior Member

    Messages:
    3,779
    Likes Received:
    1
    Joined:
    Jul 13, 2003
    Location:
    buck teeth and government checks, PA
    Ok let me try to re-phrase this. I am trying to bore out the flange on the header that bolts to the head since the diameter of the flange is approximately 4mm smaller than that of the exhaust tubing in hopes of some increased flow\ hp gain.

    Other things I would like to know:

    -Are the holes in the exhaust gasket are the same diameter as the exhaust ports on the head?

    -And since I haven’t already looked, how many O2 sensors are there and where are they located?
    Again, this is on a 95 GSR sedan
    Any knowledgeable replies appreciated, thanks
     
  6. saturn_boy96

    saturn_boy96 88 C1V1C 53D4N DR1V3R

    Messages:
    1,507
    Likes Received:
    1
    Joined:
    Dec 13, 2002
    Location:
    Sheridan, WY
    you should just try a test fit of that header first since its obx.

    since your obd1 you have 1 o2 sensor. and you should just leave your exhaust ports alone, they are supposed to be stepped like that so the shockwave in the exhaust tubing has a harder time getting back into your head.
     
  7. swanny

    swanny Senior Member

    Messages:
    3,779
    Likes Received:
    1
    Joined:
    Jul 13, 2003
    Location:
    buck teeth and government checks, PA
    I thought 95 was the first year of OBD2? :shrug:
     
  8. driver1

    driver1 Senior Member

    Messages:
    1,979
    Likes Received:
    0
    Joined:
    Jan 15, 2003
    no i beleiev it was 96
     
  9. rsaeini

    rsaeini Senior Member

    Messages:
    1,415
    Likes Received:
    0
    Joined:
    Jan 15, 2003
    Location:
    Los Angeles, CA
    just to ad to what Saturn_Boy already mentioned.

    -the O2 sensor should be on your collector, it's where the header and cat meet

    -the exhaust gasket should be fitted to your head.
     
  10. swanny

    swanny Senior Member

    Messages:
    3,779
    Likes Received:
    1
    Joined:
    Jul 13, 2003
    Location:
    buck teeth and government checks, PA
    Any more input? its all going on tomorrow.
     
  11. swanny

    swanny Senior Member

    Messages:
    3,779
    Likes Received:
    1
    Joined:
    Jul 13, 2003
    Location:
    buck teeth and government checks, PA
  12. hcivic.com

    hcivic.com Senior Member

    Messages:
    4,571
    Likes Received:
    2
    Joined:
    Jan 7, 2003
    Location:
    Calgary Alberta canada
    ya dont use a gasket to port. Gasket makes just make somthing that seals and dont research ideal port sizes. second as saturn said some poeple belive in the step method others dont it really your choice and is usally based on which works better for which aplication.
     
  13. swanny

    swanny Senior Member

    Messages:
    3,779
    Likes Received:
    1
    Joined:
    Jul 13, 2003
    Location:
    buck teeth and government checks, PA
    thanks for your input.
     
  14. hcivic.com

    hcivic.com Senior Member

    Messages:
    4,571
    Likes Received:
    2
    Joined:
    Jan 7, 2003
    Location:
    Calgary Alberta canada
  15. pills_PMD

    pills_PMD Super Moderator

    Messages:
    4,232
    Likes Received:
    0
    Joined:
    Sep 30, 2002
    Location:
    New Albany, OH
    you dont' want the header identically port matched to the exhaust porst
     
  16. JDMilan

    JDMilan Senior Member

    Messages:
    6,730
    Likes Received:
    0
    Joined:
    May 11, 2003
    Location:
    Boca Raton, FL
    don't port your exhaust ports on the head, you can clean the shit off of it but I wouldn't go ou and buy a dremel and go to town on the head..
     
  17. swanny

    swanny Senior Member

    Messages:
    3,779
    Likes Received:
    1
    Joined:
    Jul 13, 2003
    Location:
    buck teeth and government checks, PA

    i was thinking of boring the flange on the headER not the head. if all goes well it'll be in tonight, the parts didnt come in until friday afternoon so i had to hold off til tonight.
     
Verification:
Draft saved Draft deleted

Share This Page