E8X convert 135 e82 to xdrive


Oct 28, 2017
long time since last post.

okay, then story, i had small crash with my 135 e82 some weeks ago.
that`s for sure it suffers from lack of traction with all tyres except drag radials and that crash was
at least proof of it, it started to spin wheels at some 160kph and i didn`t manage to take control of it that time, like some 100 times before.

so at the same time i fix that body it will become something else, maybe first ever built 1 series e8x with xdrive.
project is starting maybe next week, i bought last week one crashed 335xi as donor car and i did some study what
has to bee changed.

transmission cross member does not fit for sure, atc300 does not fit for sure but all other parts should fit except
vargas double barrel hfpf.

one issue is unsolved, transfer case controller, what to do with that, there is no connection to that on a e8x on my knowledge and i don`t yet
know what it needs to work, but sure on 335 there must be all parts to solve that problem.

what do you think can come to be a real problem in this swap ?? all help is taken to pull this trough
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Oct 28, 2017
and oh, reason for that is obvious 29psi boost and dailydrived / weekend warrior on no prep runways.
i try to push weight to under 1450 kg levels with that xdrive fitted.


Oct 28, 2017
Hi again.
donator 335xi has not arrive yet so i have not has possibility to
do any research on how to connect atc300 controller module to a car not orginal mention
for it..

if anyone has pic of electical wiring diagram of 135i and 335xi, everything could
help on this build and maybe ideas what kind of problems is to wait for.


Nov 3, 2016
Im 100% for this idea as I thought about the reality of it as well, I would take EVERYTHING from the xi and swap it over to the 135. You will need the dme, the ABS dsx module and hardlines running from it since it is different as well.. the front suspension is also different. Your best bet would be to drop the entire front subframe of the 135 then attempt to put the 335xi front subframe into it with the motor and trans attached. Almost everything is different but you should be able to make it work with some creativity.


Oct 28, 2017
Hi again, too much work so these projects is suffering from lack of time.

the car is at the moment in paint boot cause of small accident i had with it in may, i had first test
rides with it and all most everything seems to work, except few fault codes.

there is some odd thing going on with ABS unit what is to be solved , speedo is not allways
working, 4x4 warning obvious shows when that is active, i suspect it`s one faulty wheel sensor
or steering spring unit but i have not had time to solve out it. inpa does not read any wheel speed, etc.

then dme is at the moment not with RE85 sofrware and new 4x4 trans not with xhp...

i get the car back from painter next week and get some time to solve out those odd faults.
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Oct 28, 2017
long time without any upgrade to project.

so, it took almost 1,5 month to get my 135 fixed and painted after that accident so it stretched the project by
a bit but here is the state at the moment

there was some issues after issues, most with electronics not attempted at first to e82.

mechanical assembly some 55h , problems at start is not to know what to swap, what fits and what not and assembly
sequence to all.

my e82 was manufactured 08 2007 and donator 335xi 09.2008.

to be swapped
-front struts with halfshafts

then to the not so tricky parts.

i wanted to keep 6 pot front brake calipers
so i have to make my own front discs from 335xi discs

prop shaft has to bee shortened by 99mm

downpipes is a mess to fit 4by4 because it`s to a 2wd

exhaust must bee modified cause of longer tranny (berk)

double barrel shotgun didn`t fit so i have to dump a/c to get that fit.

4x4 tranny crossmember does not have place in 135 and tannys transfer case does not fit in 135.

some small issues not to mention here.

the real issue is electronics and how to get everything work as mentioned because difference in modules, wiring harness etc.

first begin with swapping all modules from that donator just to figure out that there is no place for transfer case module but that
connection was not so difficult to dig out from tis

nightmare was to figure out that abs module is totally different on a xi than non xi with different contactor and very different pin layout so
first i did modification on wiring harness to get those modules fit just to figureout that acceleration sensor is totally different pin layout
and connector type.

then came problem with wrong abs sensors (gray ones) what should be blues, but blues did was not plugnplays. some 5 hour went with
struggling of not get speedo work until i discover that right rear wheel bearing was faulty and grey sensor was that little bit more sensitive that it worked
but throwing 4x4 faults.

i swapped that nice looking steering wheel from my donator and dashboard came from 335 too cause of right 4x4 warnings etc. but that caused
more problems, 335 dash is 5mm higher than 135 so there was modifying too.

after that i have use some 80 hour just to solve small electronic and programming issues one after another using tis, ncsexpert, inpa, ista end so on.
most time has gone with learning to use those programs and just to figure out issues that come on these kind of maybe first in world projects but is have teached me quite much on BMW diagnostics.

one of the biggest pain in the ass was fault code 5087 what seems to be mystery all over internet and i think i know reason for that. (my taught)

this kind of complains is to be found on web but there seems to be no one to tell how to solve or find real reason for it.

there is 2 different wiring harness and different transmission egs, different paddle shifter steering wheels and if you swap one of those
you can find you selve on 5087 problem. older paddle shifter use feed from paddles to gear shift lever with one upward wire and one downshift wire
going from paddle trough button assembly straight to manual gearshift swithes. paddles seems to be same with 100 ohm resistance but
resistance is messed somewhere inside steering wheel button plastics cause i xross tested parts and 135 upshift downshift version works but
the newer one wire didnt.

from on 03.2008 there was changes on that wiring, using exact same pin numbers from junction boxtrough steering wheel but there is not 2 separate output
like on older ones, on newer there is ground as one of those and one wire feed back from steering wheel trough junction box and x6021 connector straight
to transmission pin 12.

that 5087 fault code is missing resistance on one pin (12)and it must be solved with adding that cable, modifying wiring harness, or changing firmware in egs
not to waiting for pin12 be active. on newer egs gear change is done by resistance difference , my guess is at rest 300 ohm, upshift 400 and downshift 200 ohm, those values should be measured from working tranny to get that but my wiring ofcource miss the whole wire.

sorry for my english but i really hope this help someone in future.

state of the car is that all rest fault codes has been solved except seat occupancy and some head rest airbag.
then charcoal pump is missing on my car, it was usa version and there is a difference between euro and usa firmware
and now system is searching that missing pump.

next to test xdelete, xhp and trebila jb4 on this.

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Oct 28, 2017
so, at the end i have working 135 e82 xdrive, without any fault codes, everything seems to work, tune is trebila E85, xhp , xdelete just for logging
things, quaife in rear diff and got few test runs with it last evening.
tested some soft starts just to figure out how to launch this, 1st or second gear, it was on +3c paved road, low boost setting and i tried only 1/8mile
and suprice was that it is faster than my previous hoosier drag radials times full boost best launces and this is with stupidly easy launches.

i had dragy with me and tyres was my xx year old 90% used linglongs what was under the car when it came to me so it was not
the best possible startpoints but still 1.80 60ft, 3,6sec 0-60 in those conditions.
i`m sure i get with those linglongs 1,60 60ft`s and 3,3 sec 0-60 with few test launch just to figure out launch rpm, gear and throttle
usages. and what then with some grippier tires..time will tell.
Last edited:


Oct 28, 2017
there is few of issues on the project



Oct 28, 2017
First pic. small "accident" after playing around
second pic, modifying front brake to fit 6 pot caliper
third pic, rear prop shaft needed to be shortened
forth pic, some exhaust pipe adjusters, 40mm
fifth pic, that xdrive mill
sixth pic, modified floor panel to get space for transfer case
seventh pic, stock
eight pic , fitted transfer case to 135
ninth pic 4x4 subframe painted
tenth pic, different acc sensor
eleventh and twelfes pic, different abs module.

i should have huge amount of pics somewhere but in a nutshell the project goes like this

buy a running salvage 335 ix and be sure it has no damage on front axles or electronics, no burned cars.
one very very important thing is to choose right age donator, i messed that one because 135 was 09.2007 and 335xi was 10.2008
drop 135 engine, transmission, and prop shaft off body with all hardwares like exhaust, front struts, steering, etc to get
empty engine bay and transmission tunnel.
be sure to lock steering straight not to ruin uour clockspring ( i did)
modify trans tunnel to get space for transfer case, and front prop shaft

second phase is to put ix engine, front axles and transmission transfrcas as whole in the body, it fit like glowe.

parts what`s not fit is
double barrel vtto shotgun
downpipes can be trouble
exhaust is turning too close to the engine to transmission tunnel
everything is awful tight in engine bay because of front diff and front half shaft
shorten rear propshaft by some 99mm
use steering axle from 335xi , it`s longer than 135
build braxket for dbb fuel pump
learn the sequence how to get everything fitted and tighten, rear turbo intake and hot side is nasty.

that phase to get running car took me some 55 hour of labour. and i had running car but with
huge amount of warning lights in dashboard.

then ugly part. solving out what is needed from donator and what can be left from 135.
i learned hard way how this project should be build, used prox 100 hour to solve electric issue after electric issue, to be honest
75% of those could be solved with choose right 135 335 combo what i missed, i just didn`t know.

everything seems to stumble on different ABS units and 90% of elecronic issue i had was somehow involved on ABS, traction control. 4x4,
instruments, etc.

if someone need help with project like this, i think i could have some tips and hints..
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Oct 28, 2017
4 corner race scale throw out quite near 1400-1410kg in drive condition without driver
i have gone trough some degree of weight loss in the car, eg cf bucket seats, cf hood, cd tailgate,
berk exhaust, apex arc8 wheels, no rear seat, and because of vtto double barrel, i had to ditch ac because
second hpp does not fit on xi.

true weight increase from non xi xi is in a level of 70 kg and that come from transfer case, front prop shaft, halfshafts,
front diff, steel subframe, front hubs, awd ecu, halfshaft supports in oil pan,

i still have sunroof, stereos sound insulating and glass window because this is still my DD.. in a decent 29psi e85 tune


Oct 28, 2017
i have now behind me first 1500km with the car without any real issues, still missing is windshield washer fluid reservoar, and
didn`t have time for fix cruise control, it`s some parameter issue cause got it work once but messed it up somewhere in ac deleting.

other than those, not a single warning light, no need for wrenches or screwdrivers..knock knock....

feel of this thing is...somehow stunning.... it just does not do anything unexpected, just plain accelerating quite damn hard.
i tested 60 feeters on icecold asphalt with 10 year old end of lifespan liukongs and manage easy on first try1.8x with those on quite soft
start so i assume i get it to 1,60-1,70 after few practice runs compared to personal best 1,85 with 2d and hoosier dr2`s on unprep quarters
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