7875 + 5.9 + E85 + Megasquirt

Forced Induction Mopar

  1. subcom

    subcom Well-Known Member

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    About 20* timing. Everything is still super conservative with the tune. This turbo spools maybe a tad quicker than the GT45 but they are very similar. The butt-dyno tells me the old GT45 was a bit stronger on the lower end. That turbo is just a beast for what it is. I think the 7875 will do better on the top end.
     
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    • subcom

      subcom Well-Known Member

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      0EBF8240-EF7E-4E59-A3C9-9BE42458AC15.jpeg Made it to the track and got three runs in. This is on 7psi, babying it off the line and the tune extremely rich. ET is not great but MPH is a better indicator of the potential of this combo. And it felt really strong even with the AFR nearly drowning the engine. Tires broke loose in the middle of 2nd gear and got a little squirrely on all 3 runs. Bad news is I broke on the way home. Lost RPM signal, so need to troubleshoot the wiring.
       
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      • TT5.9mag

        TT5.9mag Two atmospheres are better than one

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        Great updates. Leave the fuel alone and add more boost!! That’ll take care of the rich problem. :lol:
         
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        • subcom

          subcom Well-Known Member

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          A few pics from the track and my new street shoes I’m working on. 15x5.5 and 15x8 steelies I had blasted and then I painted body color.
          294A89F8-FAC4-4905-8DEC-D68CD512FB61.jpeg 114BF130-866E-4D0B-98A9-088CD8541AFC.jpeg
          52E312DA-147F-4693-A492-036434CD66B0.jpeg 0F0AE250-377E-4E25-9809-C503C0090B20.jpeg
           
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          • turbovan

            turbovan Well-Known Member

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            Great low boost mph! How is the tuning coming along? How rich is it under boost? Any chance you’re willing to share timing/fuel table snapshots?

            I’m also surprised how quiet your turbo is. Sounds much different from my car!
             
          • subcom

            subcom Well-Known Member

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            AFR dropped to 10.1 (gas scale) under boost which can’t be possible. The motor usually drowns when it’s that rich. Not sure what is going on. Maybe O2 sensor is failing. My tuner says it’s either the E85 mix (I tested and it’s E85) or fuel pressure. When I get in front of my laptop again I’ll share my VE, AFR and Timing Tables.
             
          • dusted

            dusted FABO Gold Member FABO Gold Member

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            Same wideband or new sensor? I had a similar issue. Had car setup for 11.3 afr. Used my wideband on another project. New wideband shows 10.0. Swapped sensors and I’m back at 11.3.
             
          • subcom

            subcom Well-Known Member

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            It’s a new Spartan controller and Bosch
            Wideband. It’s funny because the AFRs are fine everywhere else except under boost. Fuel is being driven by the VE table with just a small AFR correction under boost so it can’t possibly be adding that much fuel to drive it down to 10.1. I’m going to recalibrate the wideband and cross my fingers.
             
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            • turbovan

              turbovan Well-Known Member

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              I have personally seen wideband sensorS* fail in the manor you’re describing. Fine at cruise but below a certain reading (<12.5) they do weird things. I’ve seen both dead rich and dead lean output.

              Is fuel pressure still tracking the 1:1 ratio? I know you’ve dealt with that issue in the past so I’m assuming it’s good.

              Any logs with map/ afr target/ injector duty cycle/ fuel pressure? Timing could also affect afr...depending on who you ask.
               
              Last edited: Mar 11, 2021
            • TT5.9mag

              TT5.9mag Two atmospheres are better than one

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              Not likely since you are on small boost numbers but if you’re randomly blowing out the spark under boost it will show dead rich. Just something to think about.
               
            • subcom

              subcom Well-Known Member

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              Yep, I log everything and with the exception of the AFR everything is where it should be. First thing I checked was injector duty cycle and it was the same percentage as when I’m hitting 11.5-11.8 AFR
               
            • subcom

              subcom Well-Known Member

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              I gap the plugs pretty tight at 0.020 but I thought about blow out also. Engine certainly doesn’t feel like it’s loosing spark. Thanks for the suggestions.
               
            • subcom

              subcom Well-Known Member

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              Screen Shot 2021-03-11 at 6.36.44 PM.png Screen Shot 2021-03-11 at 6.37.02 PM.png Screen Shot 2021-03-11 at 6.37.18 PM.png
               
            • dusted

              dusted FABO Gold Member FABO Gold Member

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              Is this sensor compatible with the MS3? I’ve seen Holley systems had a drop down menu and someone picked the wrong sensor and it would do weird things. Like a Bosch 4.9 being used and the ecu was looking for a 4.2. Just a thought....
               
            • subcom

              subcom Well-Known Member

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              I bought this controller and O2 specifically because it has built in support in MS and excellent reviews. https://www.14point7.com/products/spartan
              -lambda-controller-2

              I’m thinking the sensor is just defective.
               
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              • turbovan

                turbovan Well-Known Member

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                Yea if duty cycle didn’t change I’d say you’re likely looking at a sensor/controller issue. That’s good.
                 
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                • Turbosmblk

                  Turbosmblk Member

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                  Subcom, been following your build for a while between here and the turbo forums and saw where you went to the mag distributor for the cam sensor. I had the same idea as you as far as cutting the rotor shaft as I too will be doing CNP. what are you using as a “cap” since there’s no need for the traditional cap anymore. I had tried to find some info on using the Holley cap but it appears the dual sync distributor bodies are larger than the factory mopar piece. Did you just run the bolts back in the cam sensor to hold it to the body or did you make an alum. Plate of some sort to keep moisture out?
                   
                • subcom

                  subcom Well-Known Member

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                  Don’t laugh but I just have a piece of gorilla tape over the hole hiding the shortened shaft. The sensor is held to the distro body with those two little plastic nubs. An alum plate and a couple of screws would be better for sure.
                   
                • subcom

                  subcom Well-Known Member

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                  • Turbosmblk

                    Turbosmblk Member

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                    I’m not gonna knock anything while in the testing stage. How is the power with the super victor compared to the dual plane and fitech? I would assume idle quality is a lot better with individual timing and fueling compared to the old setup
                     
                  • subcom

                    subcom Well-Known Member

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                    It’s absolutely smooth all over. Like a modern car. Took a while and professional help to get it there but I love the Megasquirt...so far.
                     
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                    • subcom

                      subcom Well-Known Member

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                      Swapped out the O2 and it still goes really rich (10.1) when going into boost. The good news is I got the boost controller configured properly and did a couple of hits and reached 11.8psi at which point the AFRs came back into normal range. Inj Duty cycle at that psi is about 85% so that’s probably as far as I should push these injectors.
                       
                    • TT5.9mag

                      TT5.9mag Two atmospheres are better than one

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                      What does the 02 feedback look like in a log? Is the ecu trying to pull fuel when it goes 10:1?
                       
                    • dusted

                      dusted FABO Gold Member FABO Gold Member

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                      Not sure if it got covered but what’s the map reading? Is it tracking the same as boost guage? Just thinking out loud.
                       
                    • subcom

                      subcom Well-Known Member

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                      It’s pretty close. Hard to keep an eye on anything really under boost though.lol. I usually watch AFR closely. I might try enabling the meth spray at a little higher psi and going thru my VE table I see it’s going rich in a couple of cells that are higher than the adjacent ones. I think we bumped those up a little high to provide better quick WOT fuel.
                       
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