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Got free OBX headers, it worth it?

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  • Got free OBX headers, it worth it?

    Hey NRR,

    Is header worth it on otherwise stockish KA24DE in OBD II S14? Header came off the S13 and EGR hole has been welded shut meaning I will have to eliminate EGR and secondary O2 sensor.

    Also, does secondary O2 affects anything other then triggering CEL? It's been unplugged since I got the car a year ago and it runs little rich, but I don't care enough to fix it since last time I plugged it in, it blew one of the fuses and flooded the motor (can't remember which fuse, but ECU wasn't getting reading of many important sensors).

    I am reading mixed gain reports so I am not sure if it's worth it. Prehaps I can sell it and do a track day instead?

  • #2
    You won't pass smog test if that's an issue. The secondary sensor is there to monitor the condition of the catalyst only. Between eliminating the EGR and the header together you should pick up a few hp (maybe 5?) If the front O2 sensor is working and you're still running rich at steady state conditions, I'd double check the front sensor/fuel pressure/injectors/etc. If the secondary O2 sensor is blowing fuses it's got a short in the sensor or whatever part of the wiring you have unplugged right now. If you've been running rich for a long time, the catalyst could be plugging up. That would show up as sluggish performance that's more obvious as RPM/load increases.
    Don Johnson (really!)
    Just so you know.


    • #3
      The pre-cat on the OBD-II cars is known to die. I went through 4 of them in the 5 yrs my S14 was a street car.

      I swapped to a Hotshot header and did basically the same thing you have- chopped off the EGR and second O2 sensor, and never looked back. The car runs SOOO much cooler after unclogging the exhaust, and I noticed a small power improvement. I'm running a Hotshot header, but the OBX is just a copy of it with crappier build quality... you should see similar benefits using the OBX. Only big issue is that you won't be legal for smog. If you've run with no rear O2 sensor for years, then it's a non-issue for you anyway.

      It can't hurt-- do it. If anything, it'll drop underhood and water temps so the car is more reliable.
      Originally posted by SoSideways
      I don't care what color they are as long as they are LONG AND HARD.
      '04 G35 Sedan 6MT- The DD
      '96 240SX- The Track Toy


      • #4
        Smog isn't an issue anymore since I moved to South Carolina. Also, I forgot to mention that the header came with secondary cat delete pipe which I might be putting on as well since the cat is probably toast.

        I don't know how rich it's running, but there is a strong gas smell from the exhaust and in the cabin when windows (or sunroof) open only. Main O2 and cold temp sensor has been replaced recently. I'll look into the issue sometime.

        Is it worth spending little extra on wrapping the header before install? Does it significantly reduce engine bay temps?


        • #5
          I'm using an OBX 4-2-1 header......220whp!! I cut the outlet flange off and welded on a 3" V-band. Would like to try a 4-1 to see if I could increase high engine speed pwr. Don't mind losing a little torque down low since on the track the operating rpm range is 4500-7800.
          NASA Time Trials TT3

          BTW I work for Garrett