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3.8l V6 swap, what type of rear differential do I use?

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    3.8l V6 swap, what type of rear differential do I use?

    Hey guys, I’m swapping my 86 325 with an 3.8l V6 I found in a 90 Thunderbird Super Coupe. I went in to figure out my driveshaft and a couple people say they can’t make custom driveshafts with my stock one because the U-joint isn’t replaceable without seriously hard work. So after 5mins of research I found out you can use z3 diffs. Any idea which year z3 is easiest to fab into my rear end or any suggestions to any other methods I could use

    #2
    Originally posted by Bpace86 View Post
    Hey guys, I’m swapping my 86 325 with an 3.8l V6 I found in a 90 Thunderbird Super Coupe. I went in to figure out my driveshaft and a couple people say they can’t make custom driveshafts with my stock one because the U-joint isn’t replaceable without seriously hard work. So after 5mins of research I found out you can use z3 diffs. Any idea which year z3 is easiest to fab into my rear end or any suggestions to any other methods I could use


    Z3 diffs are a swap in however they don’t actually solve your problem.

    You’re going to probably end up needing a driveshaft made with 1310 yokes. 1350’s don’t fit the rear subframe.

    I have been down a similar road with my 1uz swap. In the end I’m custom machining an adapter from 350z to e30 diff. I do have a 1310 to BMW input which is new and I haven’t ended up using for $100 shipped.

    You might get lucky with a standard length driveshaft but you’ll need one of the mmc ones because of critical speed.

    Have you figured out the exhaust and brake booster yet?


    Sent from my iPhone using Tapatalk

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      #3
      Why You Might Need One. When doing a V8 swap into a BMW, the BMW U-joint is non-serviceable and requires special machining to replace. Stealth Conversion’s heavy-duty BMW driveshaft conversion flange has the same bolt pattern and pilot dimensions as the stock BMW driveshaft flange, but it uses the road-tested Dana 131
      84 325e - 91 325i - 92 318 touring - 91 Trans Am - 01 S4 avant - 03 S-type R - 96 F350
      Manual swap all the things!

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        #4


        That’s what I have. Brand new and shipped for $100.


        Sent from my iPhone using Tapatalk

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          #5


          Dang, I haven’t been on the Jags That Run site in a hot minute. Following this thread to see if this swap comes to fruition.


          Sent from my iPhone using Tapatalk
          1991 325i MT2 Touring (JDM bro)
          2016 Ford Flex
          2011 Audi A3 - wife's other German car

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            #6
            Originally posted by djjerme View Post
            Dang, I haven’t been on the Jags That Run site in a hot minute. Following this thread to see if this swap comes to fruition.


            Sent from my iPhone using Tapatalk
            FWIW, I used that adapter and had NW Drivelines make me a one piece driveline for my volvo swap. Fits 98% perfect. I had to "massage" the underside of the gas tank and shield because the weights used on the driveline scraped against them. Otherwise, JUST enough room.
            84 325e - 91 325i - 92 318 touring - 91 Trans Am - 01 S4 avant - 03 S-type R - 96 F350
            Manual swap all the things!

            Comment


              #7
              Back when I was mostly in the GM world and contemplating a TPI swap in to something, they did a lot of the custom swap driveline bits. But shoot that had to be maybe 20+ years ago?


              Sent from my iPhone using Tapatalk
              1991 325i MT2 Touring (JDM bro)
              2016 Ford Flex
              2011 Audi A3 - wife's other German car

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