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Differences between Pro-Flo XT(35443) & Pro-Flo 4 XT(35920)

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  • Differences between Pro-Flo XT(35443) & Pro-Flo 4 XT(35920)

    I purchased the PF XT 35443 a few years ago new and installed it but never could get it to run properly, my question is; Is it possible to upgrade my system to the PF 4 XT 35920? It looks like the same intake and distributor perhaps?
    Can I change the Ecu, harness , etc. to make this into the newer system? I believe I may have better luck with a self learning system, If I had realized the difficulty I would have with the older(35443) system I would not have bought it, I can find nobody local that knows jack about the one I have, I've contacted your tech people and while they are helpful I just think the task is beyond my level.
    I'm not 100% sure the newer model would make this easier ? I don't want to throw good money after bad , but I have several $K wrapped up now and it's not what I hoped it would be...

  • #2
    Not much difference from 3 to 4. So you really need to explain in detail what your issues are. Send a recording of all the readings while the problem is happening. What is the problem, what is your fuel pressure , what map is installed. what is your afr reading,


    • #3
      He has a original XT. Not a 3.

      Do you feel confident to crimp your own terminals?
      At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy


      • #4
        Yea should of caught that.


        • #5
          The XT and the 2 are the same. They just used different IAC's. 2 wire for the Pro-Flo 2, and 4 wire for the Pro-Flo XT. So they used different maps .

          It's not to hard to wire up a Pro-Flo XT harness to a Pro-Flo 4 ECU. You need a main connector, and New O2 sensor, and it's matching connector.

          To do a Pro-Flo 2. You need a new throttle body.
          At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy


          • #6
            I have no problem with wiring and terminals etc. , So I can get the newer ecu and connector from edelbrock and the rest will stay as is, I put a wideband 02 sensor from dynojet that was recommended in the installation manual, is that going to work or is a different one required?


            • #7
              I'll draw up a diagram tonight.

              To get the main connector for the Pro-Flo 4. Digikey looks like they have all the pieces for about $50.00.
              Summit racing has the ECU. It's a little bit over $500.00 now.
              I'll post all the bits and pieces need for the conversion, with the wiring diagram tonight.
              At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy


              • #8
                Great, I found the ecu at jegs for 520, probably same as summit, Thanks for your help on this !


                • #9
                  Little update on the diagram and parts need:

                  I'm still ruffing out the drawing.

                  The O2 sensor is 6 wires, and will most likely be all new wires, and connector from the ECU.

                  The relay for the fuel pump will not be changed.

                  A "main" relay will be needed.

                  A fuel pressure sensor will be added to the diagram.

                  For the LS motors I might do a diagram replacing the IMU.....that's the multiple coil driver. The Pro-Flo 4 can do a wasted spark firing order, with it's 4 coil outputs.

                  The DB9 connector will be new, with wires.....personally, I wouldn't wast time hooking one up. I would run wires. But I wouldn't install a DB9 connector.
                  At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy


                  • #10
                    Let me know if you need any info , Thanks


                    • #11
                      Time to pump the brakes guys. Unless you're an experienced wiring harness builder, I definitely would not venture into trying to make a new harness or try to convert an old one. The Molex CMC connector system on the Pro-Flo 4 ECU uses two different sized terminals, both of which require their own specific crimper that usually costs over $400 each. Each terminal size also requires their own specific unique depinning tool that are also over $100 each. You'll spend $1000 to just get the appropriate tools to make a harness. I wouldn't even attempt to use any kind of universal crimper with these terminals - it won't go well. If you're frustrated and having a hard time now, wait until you try making your own wiring harness. Plus, Edelbrock will be under no obligation at all to provide support for any kind of "custom" made system that uses a Pro-Flo 4 ECU.

                      Unfortunately there is no direct upgrade from any legacy Pro-Flo system to Pro-Flo 4. Your best bet is to buy a complete new Pro-Flo 4 and maybe you can part off some of your old parts. The kit is so competitively priced as a whole that a pieced together upgrade kit winds up costing almost as much as the entire kit. Call in and talk to our tech to discuss more.


                      • #12
                        If I were to get a #35920 , Is there any difference in the manifold , fuel rails , injectors , etc ? basically can I leave the manifold mounted ? same question about the distributor although that's an easier thing to swap out.


                        • #13
                          Hard parts are the same. The distributor needs to be changed. Please give our tech a call to discuss further.


                          • #14
                            Thanks, and Thank-You BITE-ME for the efforts you put into this !