Honestly, I haven't even been under it lately as I'm on an extended trip to Seattle before I goto Abu Dhabi for a year. Mechanically, since it's the same engine for the 540, 740 and X5, there is no reason why bolting a 6spd and getting a custom driveline made wouldn't get you a RWD only X5. Since the 740iL doesn't come in 6spd (740i's in Europe only, still no iL's), I had to get a driveline made...cost around $400 shipped to my door.

Do you know how many people say the same thing and never do it? It's the biggest dream and the biggest budget as well. Sure, it's a similar block with a larger bore, but everything above and beyond that is entirely different and it's not realistic. I've seen maybe 1 S62 conversion that was done into a 740iL, and god only know how it truely drives on the road and in real world conditions because it was made into a show car, so the most road time that vehicle probably gets is on and off a trailer. You make it sound like the proper wiring is just something some guys can do in their garage over a weekend...it's not that simple. If someone it serious about doing this, save the $5-8k you'd blow on the engine alone, throw a custom turbo kit or a premade S/C kit from VF on there for around $6k and save yourself the wiring headache of an engine conversion.

Realistically, no shade tree mechanics will be swapping S62 into an M62 chassied car anytime soon because the dreamers realized how cost prohibitive it truely is. I looked into it as well since I had to replace my 7's engine within 4k of ownership. Swapping an LSx engine would be 10x easier (because it's been done plenty of times) and they have an obscene aftermarket following...do that, then we'll talk.

No difference there, that's engine displacement. You definitely could pull it off, but most likely you would lose your AWD, due to computer problems.\

To be honest, I'd love to do an S62 swap in my truck and make it into a true, one-of-none E53 X5M, but after seeing the amount of time it's taken to get one working in my friend's Z4, I don't think I could bring myself to do it, unless I got a motor stupid-cheap and could figure out a way to wire it right. I think the best approach would be to wire up the ITBs as a single unit and use 1 MAF, so that the factory computer could just think it's an M62. As far as VANOS, I would think an RPM window switch would work on that too.

Engine displacement has no relation to the transmission as they're two completely different things that are only tied together via a bellhousing and some bolts. I've seen a handful of 3 series (one being a touring) that had a LSx motor dropped in but still using the stock BMW transmission because they had a bellhousing made so the two could mate up. The V8 engine in your X5 is a block that has been around for YEARS before the X5 was even being produced, ranging in displacement from 3.0 to 4.9 and has been used in 5, 7 and 8 series vehicles that could fit a V8 between the frame rails. The M5 6spd that I dropped into my 740iL is actually the same trans used in the 540, 840, etc...but it sounds cooler in my sig to say M5 6spd :)

It's been done, but I'm not sure if it's AWD anymore. While having AWD is nice in Boise winters, I'd rather have a 6spd manual for the increased gas mileage (gained 4mpg in the 740iL) and cool factor for the other 9 months when it's not snowing...AWD is for people without track experience and/or vehicle control skills ;) I would just as easily drive my no traction control having M5 to work just as I would taking the X...and I've done it before.

Yeah, but S62 + blower + AWD = AWD burnouts = Gnarly.

I forgot to reply to this when you first posted these pics, but the bellhousing, transfer case, etc pics that you posted are irrelevant since whoever does this is going to be swapping in the 540/M5 transmission in anyways, so unless they're attempting to somehow keep the AWD system, all that would be required after the trans swap would be a driveline as I did in the 7.

What did you do to trick the ECM and/or TCM so they think the auto tranny is still there and working normal? How different do you think the electrial aspect would be different with an 01 x5?

Taking out the front diff, diff casing, cv joints would save a bunch of weight too. That 6spd 740iL swap sounds super sweet.

It's just programming on the computer. Before people we're coding the cars to make them think they were 540's instead of 740's, but people have found ways around that in case they had custom software that they didn't want erased and are able to just get the 540 transmission software parts of the code transferred over instead of the whole ball of wax. The X5 would be an interesting attempt since it's similar yet different to the 540/740, but still it's own beast with the AWD system. My 740iL is non VANOS as well, so it's not like I could copy the code from my 740iL onto a VANOS X5 for the sake of saving time. It'd take some work, but I don't doubt it can be figured out one way or another. At worst, if not coded, the vehicle will still drive, you'll just have constantly nagging transfail safe codes on the OBC.

I agree that the weight savings would be pretty substantial. I take out the spare tire everytime I'm back home in Boise and then throw it back in for roadtrips just for the sake of saving weight while doing my normal driving around town...that damn spare is heavy! There is like 10% more loss between the auto compared to the 6spd, so gas mileage went up as well. Compared to some other's, my 7 is still pretty stock even with the 6spd since I still haven't gone FI...the biggest difference still being my engine rebuild. There are a few 740's floating around with 6spd and superchargers, or Rob from UUC owns 750iL with an 850csi 6spd transmission swap. It's still a pretty unique upgrade, so I'm happy to be part of a select few. Next major mod...STS style turbo :)

James, if one put in a 540 transmission and wanted to keep the AWD odds are most likely the tail shaft can be unbolted and the transfer case fitted on as long as the splines are the same.

Now as I say this my only real life experience with this is on old fords... we made a 2wd bronco the same weekend a making an E150 van 4wd. Bronco got lowered sport suspension and hopped up 351w w/5 speed manual and the van got 4" lift w/38" TSL boggers and a built 351c paired to a beefed up C6 auto. (that was a fun mudder!)