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Thread: E38 vs E39 LSx swap questions

  1. #1
    Join Date
    Jul 2012
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    Philly suburbs
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    97 740i 06 silverado

    E38 vs E39 LSx swap questions

    Hey everyone just picked up a $350 97 740i with the intentions of swapping a turbo 5.3/t56 combo into. I've looked through the swap sticky already but still have some questions

    My game plan is to use an E39 I6 subframe to shed a little weight and gain rack and pinion steering and use jesus freak mounts to get everything in place.

    The mechanical and Fab part is easy,the part I'm concerned about is the wiring, the actual act of splicing in is no big deal but info on an E38 swap is scarce and no one seems to finish one so my big question is E39 wiring similar enough to use as a reference?

    Also from some research I've done it looks like a lot of people piggyback the GM PCM off the DME is there a reason for that or can I just use the GM PCM and retain full functionality?

    Any other tips, info or issues I may not be thinking of would also be appreciated.

  2. #2
    Join Date
    Aug 2005
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    VA
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    E63AMG/Z31/Tacoma/F31
    I would argue that the wiring is the easier part since it should be about the same as the e39 with plenty of documentation on here. The fab part is what stops most e38 owners. No one makes engine/trans mounts or manifolds/headers. Also not sure if the auto kraft oil pan several of us e39 guys used fits the e38

  3. #3
    Join Date
    Oct 2008
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    '00 540 6.0/4L80e/S480
    I'm curious to know of the E39 subframe actually fits. If it does, you will be in good shape with known oil pan and mounting options. The wiring isn't all that hard. Most stand alone harnesses need a constant 12v, switched 12v, ground and fuel pump trigger. These aren't difficult to find, but it takes a little patience.

    My .02 is try the subframe. If that works, the remainder is not difficult.

  4. #4
    Join Date
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    E63AMG/Z31/Tacoma/F31
    The GMPP E67 ecu kit makes the install much easier but it is a little pricey.

  5. #5
    Join Date
    Jul 2012
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    Philly suburbs
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    97 740i 06 silverado
    I've heard that the subframe does fit but I don't think I've ever seen one actually do the swap so I was hoping someone with some knowledge about that might chime in because in an ideal world I'd like to be able to use my lift at work and drop the bmw's engine trans and subframe as a unit then slide the ls/t56/E39 subframe under it and in we go. I have seen the gmpp kit my buddy used it on his g body ls swap and it is nice but I don't mind modifying a harness.
    Certified Ford Diesel Senior Master Tech

  6. #6
    Join Date
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    I asked this question prior to buying my E39 and wasn't able to find anyone that had actually done it. The "in theory" stuff was out there, but no real world experience.

  7. #7
    Join Date
    May 2017
    Location
    San Diego, Ca,USA
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    5
    My Cars
    00 E38 Msport,11 AMG G55
    Pirate did you actually do the subframe swap? I am strongly considering doing the same to my 2000 sport short. Close examination of the two subframes on Ebay shows one minor difference in that the e38 has a dowel on the subframe which goes into a hole on the car frame vs. the aluminum subframe which has the hole in the subframe to go on the dowel on the car frame. Simple solution looks like machining a dowel pin with a hole in it to connect the alum frame to the car with the bolt passing thru to hold in place. I believe the hubs are similar so just need a steering rack and all the I6 suspension arms. Would certainly make for a cleaner swap install. Curious as to how the car would Feel with the Rack vs. the Box. Also the Msport has variable assist steering and the rack doesn't, so don't know if that would make any difference.

  8. #8
    Join Date
    Aug 2011
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    Tampa, FL
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    2002 M5 & 1991 850i 6spd
    https://levelsperformance.com/produc...train-swap-kit

    I sent a message inquiring, but I haven't heard back.

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