M62TUB44 vs M62B46 - interchangeable?
 

Hello.

I did some google search and searched this forum as well as some others, did not get a definite answer to my question...

I presently have an 2002 E53 X5 4.6iS that needs engine work, and sourcing parts is a financial nightmare, and considering a replacement M62B46 is equally nightmarrish... However, I have seen plenty of M62B44 and M62TUB44 floating around at rather affordable rates...

Besides the obvious of demoting of the beast to the regular level, is it possible to drop an M62TUB44 in place of the M62B46 engine?

If it is possible, what is involved in making sure it is working properly? Will the ECU and the rest of the brains communicate as it is, or some reprogramming must be done? are there incompatible parts? It will not be a DIY project, a professional mechanic will do the work but I wanted to be on the knowlegable side of the issue.

I know that some people pull I-6 in favor of V8s in some racing applications, thus "upgrading" the car - I just want to get the thing back on the road...:(

This plea is out of desperation, as my wife wants a divorce from the 4.6is and I hope to save the car's dignity instead of abandoning it somewhere under a bridge on an interstate!!!!ouch:

The opposite conversion has been done in an E39. While functioning, the swap was not seamless at all. It involved a lot of harness changes, programming differences, etc. I did not ever hear if he ever got everything worked out.

While his upgrade was the opposite direction and on a different chassis, it can be reasonably assured that the challenges would be very similar.

What's up with your 4.6 motor?

I would think the block and most of the accessories would be nearly identical on both motors, the tune would be different though.

Depending on what kind of parts you need, maybe there is something aftermarket available? ie; pistons, rods, valvetrain

the chain guides went dead, the chain slapped around long enough to break one of the engine covers and bend some pistons or valves or who-knows-what - just long enough for me to pull over from the main lanes of traffic onto a side street... Damage was done...

the mechanic thinks that it would be better to get a replacement engine, but this particular engine is rare, and whatever i can find costs a lot... the car with fully functional engine tops at $12K maximum, with a generous buyer... dropping $6K-$8K into this car makes no sense... I was hoping to get a $1.5K-$2K M62TUB44 and get it up and running for the local errands, nothing long distance anymore...

I am no expert but I guess it might be doable if you can get the ECU that belongs to the motor.

do an S85 swap :D

I think your first step is opening it up to assess the damage. You might be able to rebuild the motor. If not, bolt the 4.4 in there and fire it up. I'll bet it runs on the 4.6 ECU.

Is there room for the V10 in this thing? :thumbup:

V10???

wow!!! years ago, I chose the nik Terminator, because this thing would terminate anybody's attempt to pass it on a highway... I had taken that particular car to 140 MPH and it was rock solid...

Over the years it had gathered some battle scars, some are just "tissue" deep and some were more heart-breaking... It is like an old war horse, I just don't have enough guts in me to part it out, but getting a full fledged 4.6 engine is hurting the wallet...

I was thinking about 4.4 V8....

But if I will get the V10 then maybe I will have to change my nik to

FrankensteinX5!!!! Unless it is already taken... lol...

V10 will cost a lot more. I bet it doesn't run with a 4.4 motor with a 4.6 ecu. You would probably need ecu, cluster, and harness. Then you would need to code all the electronics to new ecu.