Announcement

Collapse
No announcement yet.

O2 Sensor/headers question?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • O2 Sensor/headers question?

    Hey guys-

    I'm eventually going with a FI/TBI system. I'm installing headers in to my Scout 2, with 345. Which header and where do I place the O2 sensor? Also, would it be the same location for a 392? I have plans of installing a 392 in the future.

    Thanks

    HD

  • #2
    This picture will help without headers.
    Attached Files
    [CENTER]1994 Buick RoadMaSSter Estate Wagon LT1/4L60E. White and Woodgrain Sleeper...PCM 16188051 With SS/V4P/Custom Tune! WOT 12.9 AFR!

    1990 Chevy Suburban Silverado 5.7L 2wd ECM 1227747 HiWay Lean Cruise 18.5 MPG and 12.5 to 1 AFR at WOT!

    1972 IH 1210 Isky Cammed Balenced 345 4 speed PCM 16197427 Project!

    [SIZE=3][B][URL="http://www.gearhead-efi.com/"]GearHead-EFI.com[/URL] EFI Conversions and Chip Tuners![/B][/SIZE]
    [B]May be all you need to know about EFI![/B]

    and I still help local JustIH members (for fun) free! :cool: [/CENTER]

    Comment


    • #3
      Re: O2 Sensor/headers question?

      Originally posted by hoosierdade
      Hey guys-

      I'm eventually going with a FI/TBI system. I'm installing headers in to my Scout 2, with 345. Which header and where do I place the O2 sensor? Also, would it be the same location for a 392? I have plans of installing a 392 in the future.

      Thanks

      HD
      The sensor has to be heated to operate. There are 2 ways to do this.
      1. Let the exhaust heat it up as the motor runs.
      2. Use a heating element in the sensor to heat it up.

      Now for mine . I run a 1 wire O2 sensor and stock exhuast so I mount it on the pipe as close to the manifold as I can. so it heats up fairly quick.

      Now for headers there is 2 ways to go.

      1. mount a 1 wire sensor about 6 inches from the head so it will heat up.
      down side is with headers you will only be sampling one cylinder.
      or
      2. go with a 3 wire sensor(built in heater) and mount it down on the collector. The heater will only require 12v and gnd so it's not a big deal.

      Now some other variables could be on tri-Y headers to put it at one of the Y's. Again should be heated or at the least heat wrap the headers to retain the heat in.
      I'm sure there are others, but that will get you thinking in the right direction.

      Start looking at the late model headers in the catalogs and see where they are mounting them. (O2 bung)

      and no motor size won't matter.
      HTH
      Bill USN-1

      COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
      HAMILTON FUEL INJECTION
      May be the answer to all your fuel injection needs!
      Learn to do it right.

      Comment


      • #4
        I'm running "header's by stan", which is a 4 into one collector set-up.

        I didn't realize the "heat" issue. Thanks for the input.

        Is there any draw backs of using a three-wire/heater-type O2 sensor?

        HD

        Comment


        • #5
          Price !
          [CENTER]1994 Buick RoadMaSSter Estate Wagon LT1/4L60E. White and Woodgrain Sleeper...PCM 16188051 With SS/V4P/Custom Tune! WOT 12.9 AFR!

          1990 Chevy Suburban Silverado 5.7L 2wd ECM 1227747 HiWay Lean Cruise 18.5 MPG and 12.5 to 1 AFR at WOT!

          1972 IH 1210 Isky Cammed Balenced 345 4 speed PCM 16197427 Project!

          [SIZE=3][B][URL="http://www.gearhead-efi.com/"]GearHead-EFI.com[/URL] EFI Conversions and Chip Tuners![/B][/SIZE]
          [B]May be all you need to know about EFI![/B]

          and I still help local JustIH members (for fun) free! :cool: [/CENTER]

          Comment


          • #6
            Originally posted by Eagle-Mark
            Price !
            HD,
            I am running Stan's Tri-Y headers on my 392 with Holley ProJection. I am using a 1 wire O2 Sensor mounted about 1.5 inches below the gasketless collector fitting, so it's about 16 inches from the head. By the time the H2O is up to temp., the O2 sensor appears to be working. Maybe I'll have some trouble in the snow, but so far, it has worked fine.
            (I am going to become familiar with the 3 wire O2 sensors, just in case.....).
            Mickey

            Comment


            • #7
              little dog-

              In my past experience, the hottest area of a standard style header is between six to ten inches away from the head. I was thinking of putting it just below that point. I just want to make sure That I don't get the sensor to hot. I've seen the mentioned area get as hot as 1200F (if motor is running lean). That was on race motors, not an IH.

              HD

              Comment


              • #8
                pics

                Bill USN-1

                COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
                HAMILTON FUEL INJECTION
                May be the answer to all your fuel injection needs!
                Learn to do it right.

                Comment


                • #9
                  pics

                  Bill USN-1

                  COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
                  HAMILTON FUEL INJECTION
                  May be the answer to all your fuel injection needs!
                  Learn to do it right.

                  Comment


                  • #10
                    Re: pics

                    Why would they have a duel O2 sensor? Are you sure those headers aren't for crank case evacuation?

                    Hey Bill, here's another question. Theoretically, if I wanted to run a cross-ram intake manifold, normally used to run two-four barrels carburetors, on a big-block Mopar, would it be possible to run two TBI systems instead? Would I have to run two O2 sensors, one per bay of cylinders? I have any Idea for a 1970 Dodge Challenger.

                    Thanks,

                    HD

                    Originally posted by Bill usn-1

                    Comment


                    • #11
                      dual setup

                      Chev already did it on the vette. grab the whole system.
                      dual TBI's!!
                      Some guys on the diy-efi site are working on using a different computer like the 7747 we use to drive it since it has 4 injector outputs already. as for the dual O2's that depends on the computer. The 7747 does not provide fo a dual O2 that I've seen. But I know some of the computers out there do.
                      I've even heard of some of the imports using 4. 2 before the cat and 2 after!!

                      The full length headers were for a 302 EFI. Not sure if it is stock with 2 or just give you the option of which side to use.
                      Bill USN-1

                      COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
                      HAMILTON FUEL INJECTION
                      May be the answer to all your fuel injection needs!
                      Learn to do it right.

                      Comment


                      • #12
                        Thanks Bill-

                        The Fuel Injection project will be interesting.

                        What about Temperture? What happens if the O2 sensor gets to hot?

                        HD

                        Comment


                        • #13
                          too hot

                          Originally posted by hoosierdade
                          Thanks Bill-

                          The Fuel Injection project will be interesting.

                          What about Temperture? What happens if the O2 sensor gets to hot?

                          HD
                          Never heard of it. yet
                          I guess you run the risk of burning it out.
                          Did you see the V-10 header?
                          I think that would be more heat than we could generate!
                          the O2 sensor has a finned cover over the tip of it so it should be shielded some.
                          Bill USN-1

                          COMMITED TO TEACHING PEOPLE THE "PROPER" WAY TO EFI
                          HAMILTON FUEL INJECTION
                          May be the answer to all your fuel injection needs!
                          Learn to do it right.

                          Comment


                          • #14
                            Interesting info.

                            Thanks,

                            HD

                            Comment


                            • #15
                              O2 and Headers

                              Hey guys I read this and there are a few things that you should know about O2 sensors.
                              First the units that have 2 before and 2 after the cat is an OBDII application. the second one is looking at the amount of break through of the cat and if the amplitude is to great it will set a check engine light and tell you that the cat is bad.

                              Second there is only one reason that there is a heater on an O2 sensor, emissions. On modern vehicles it is almost imperative that the engine control remain in closed loop all the time in non power enrichment modes to maintain the proper emission levels. This is the only reason for the most part. If your O2 gets cold the system simply goes into open loop until it warms up again. No issue unless your open loop fuel table is way off and then you have other problems. Some of the 7747 calibrations actully go into open loop after a short time at idle even if you are keeping the O2 at 1,000 degrees.

                              Third engines have 2 O2 sensors simply again for emissions. What you find with vehicles is that one bank may run a little bit leaner than the other bank, by leaner I am talking tenths or hudreths of an air fuel ratio. For you an me this means nothing, but for emissions it can be the difference between passing and not passing with the modern engines. One O2 is all that is needed for your purposes.

                              Fourth with headers put the O2 in the collector on either side and don't worry if it cools off, it is not going to hurt anything. If you want to insure that it always stays in closed loop then go ahead and use a heated sensor.

                              Comment

                              Working...
                              X