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    Automatic differences: eta vs i

    I have an automatic 92 325ic. The engine is currently not running. The purpose of this car is to be a dirt cheap daily driver and cruiser for my girlfriend.

    I also have a 5 speed 87 325es. The engine runs well, but the clutch is gone and the shell is rusted out. It's a parts car. And no, I am not 5 speed swapping the vert.

    (Flame suit on,) I am toying with the idea of putting the eta engine into the vert. Yes, I realize that etas are slow, automatic etas are slower, and an automatic eta convertible will be slower than a one legged dog on tranquilizers. My concern isn't with speed, it's with cost. If they will interchange easily, it would be free for me to do this.

    What I want to know is whether I will run into issues with how it shifts, whether it will be able to figure out the different torque curve, and make sure it won't downshift into an RPM higher than the low eta redline. Will this be all be carried over with the eta dme, or is there a separate auto trans computer, and is it different than mine. I know for 5 speeds the e and i g260s were different. Were there different different versions of the zf h4p22 too?
    What it feels like owning an e30:

    88 325 S50 swap in progress
    90 325ix


    #2
    There was only early and late Getrag, my 86 eta had the late style shifter provisions and now resides in my 90, the gear differences are in the diff. The biggest thing I think you will have to worry about is weather or not the auto you want to use has the bell housing crank sensor holes.
    john@m20guru.com
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      #3
      The eta makes a great automatic due to great torque. Great set-up for a GF unless she is a gear head. The automatic is no issue and most E30 cars did not have an electronically controlled automatic. Do you have any controls for the automatic in the cockpit? You would need to swap differentials as all eta cars used the 2.79 or 2.93 ratio. Also, the tach and code plug need swapping.

      The electronics on the engine could get a little sticky though. I am assuming an 87 eS has the round 101 engine harness plug, but I'm not sure if you would be able to just plug the eta engine into the car harness and have everything work - for example, the tach.

      I have always wanted to try a 1.3 Motronic system on an eta engine. It would be possible to just run the 92 iC engine management on the eta engine, but you would likely need super eta injectors (I'm guessing), swap the front balancer and figure out a tune with a rev limit (it might be possible to get a distributor rotor with a rev limiter built in but I have never heard of one. I have also never heard of anyone burning a chip for a stock eta engine with the 1.3 Motronic upgrade.

      Anyone else help here???

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        #4
        87 will have the round plug, but the eta DME does not send the tach signal through the engine harness, it plugs in behind the dash. Tach wouldn't need to be changed unless it bothered you that the redline wasn't true anymore, they are both 6cyl cars.

        A chip could easily be made for a rev limiter, but the rest of the tune would be off, someone would have to take time to make a whole new file.
        john@m20guru.com
        Links:
        Transaction feedback: Here, here and here. Thanks :D

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          #5
          Might approach SSSquid about it - never know?

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            #6
            You would want the motronic setup from the Cabrio including injectors to avoid a motronic down grade.

            the Cabrio has a different torque converter which is obviously intended to compensate for the different weight of the car. I also think if you are dropping power in the heavier Cabrio you may want to leave the 3.73 diff in place so a) it will move faster than s snail and b)so you don't add even more unintended load to your already under rated torque converter
            Last edited by jeffnhiscars; 02-18-2016, 04:30 PM.
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              #7
              Still looking into this. If I do it, I probably would just use the whole Eta engine management since it would be the easiest option. As for wiring, I could check the plugs and see if there are any major differences. I don't need dummy lights to work right away, just need to get it running.

              I have a lead on an automatic Eta parts car for pennies with a good drivetrain minus the engine. Don't know if the trans itself is any different (anyone have insight into how it determines shifts?) but it would be cheap insurance to have a trans that I know was used with this engine. Am I right in thinking I should use the cabrio torque converter instead of the Eta one?


              Sent from iPhone
              What it feels like owning an e30:

              88 325 S50 swap in progress
              90 325ix

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                #8
                I would stick with the Known-good converter especially if the fluid was clean

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                  #9
                  ...and I would keep the torque converter with the engine, as it'll have a lower (stiffer?) stall characteristic to match the eta torque.


                  I agree, for pootleing around, the eta's ok, and with the top down, who cares that you can't hit 100mph? I don't think a 3.73 would be good if it was going on the freeway, tho...

                  t
                  now, sometimes I just mess with people. It's more entertaining that way. george graves

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