E30 M3 S62 Build - Loads of queries about 4x4 drivtrains

[nando]

The E53 X5 front diff does not require electronics.
All the front diffs (except maybe the E30?) use 168mm ring (crownwheel) & pinion gears just like used in the rear of 4 cylinder cars.

I discovered they're all 168mm carriers (including the E30). The E30's carrier is the narrowest, lightest, and at the same time, the weakest.

The E46 unit *MAY* interchange with the 168mm carrier used in the 2002. There is a Quaife for that application as well. Similar caveats apply.

IIRC, the E34 carrier is in between these two in width.

unfortunately, I don't think it will. they're several MM apart (I've got an E46 carrier and dimensions for all the other 168mm carriers). the E34 carrier is a little narrower than the E46, but mainly the ring gear on the E46 is much thicker (due to the wider range of available ratios in an E46 diff case vs a single ratio for the E34), and the pinion shaft is larger, otherwise they're similar in size.

also, I believe there's a reason BMW doesn't use a front LSD. the only time I could see it being a benefit would be off-road. It would really only help if both rear tires lost traction in addition to one of the fronts.

[The Dark Side of Will]

The E53 X5 front diff does not require electronics.
All the front diffs (except maybe the E30?) use 168mm ring (crownwheel) & pinion gears just like used in the rear of 4 cylinder cars.

The E53 front diff uses a "wide" carrier that shares dimensions with the 4 cylinder Z3 unit. The Quaife for the Z3 4 cylinder works in the X5 front diff. However, if you're going to do that, you'll need to disassemble the Quaife and turn the gears around, because in the front end application, the torque is in the opposite direction from the rear end application.

The E46 uses a narrower front carrier than the X5. The E46 unit *MAY* interchange with the 168mm carrier used in the 2002. There is a Quaife for that application as well. Similar caveats apply.

IIRC, the E34 carrier is in between these two in width.

[Turk]

Unimog... :p

Haha, don't think my jack would get anywhere near to lifting one of them off the floor :D

I have been having a look at a few tcases, but most that come up seem to have some sort of electronic controller needed.

I want a good old fashioned 33/66 or 40/60 splitter.

Btw does the x5 front diff need any electric-tronics?

cheers

[The Dark Side of Will]

Unimog... :p

[Turk]

lol, not mocked up just a pile of parts.

Which transfer cases would you have considered if you had been on this side of the pond?

Ive been looking at land rover gearboxes etc as some have bell housing to match bmw v8s, but tc's are on the wrong side :(

[The Dark Side of Will]

Ratio wise I don't think i will be able to put up with 5 speed. I definitely need overdrive as i will be doing a fair bit of mileage and want to have a nice low cruising ratio.

I certainly wanted to be able to utilise the m5 6 speed. Back to the drawing board.

This is what I have so far btw: an ix subframe and x5 sump, Im looking for a scrap v8 block to bolt up temporarily for measuring etc.

Not sure if this is supposed to be a mock-up, but you have the crossmember backwards

If you require a 6 speed, your best bet is probably to modify the rear case of a 420G to mount up the T-case of your choice.

The lack of overdrive really kills that 5 speed.

[The Dark Side of Will]

it bolts directly to the ZF 310/320 (that's my pic) :)

I didn't know you were Chris :p

[Turk]

Ratio wise I don't think i will be able to put up with 5 speed. I definitely need overdrive as i will be doing a fair bit of mileage and want to have a nice low cruising ratio.

I certainly wanted to be able to utilise the m5 6 speed. Back to the drawing board.

This is what I have so far btw: an ix subframe and x5 sump, Im looking for a scrap v8 block to bolt up temporarily for measuring etc.

[The Dark Side of Will]

Early E46's used the S5D with yet a different rear case half.
Later E46's used the S6S BZ370 or some such that is a 6 speed, yet is not the 420G used with the M60 series engines.

If you won't settle for a 5 speed, you're in the same boat I was in.

[Turk]

is there a chance anything would fit the 6 speed? maybe an e46 xi rear end?

[nando]

so are we saying the back end of an e30/e34 gear box (below) will fit on the e34 v8 5 speed or maybe even the e39 m5 6spd?



Or will this need to be spaced out from the back of the tranny, i.e. having it welded onto the back?

it bolts directly to the ZF 310/320 (that's my pic) :)

The Dark Side of Will: I agree to disagree. I don't think there's any reason to believe either T-case couldn't handle an S62. But, it's more on principle. I think using a GM t-case with a 60/40 split and VC lock is a great idea since it's basically the same exact thing, and there are other packaging issues to consider, plus it's domestically available and relatively cheap. I mainly suggested the E34 parts due to his location - finding one there will be far easier than it is here in the states.

I also think an E30 front diff wouldn't last 5 months! :)

[The Dark Side of Will]

remember, only 1/3 of the torque (approximately) is going through them.

100% of transmission output torque (4.2x engine torque in the case of the S5D) is delivered to that planet carrier.

so are we saying the back end of an e30/e34 gear box (below) will fit on the e34 v8 5 speed or maybe even the e39 m5 6spd?

http://www.325ix.com/photos/index.php?action=resize&file=2011/S54ix/11-05-2011/DSC00278.JPG

Or will this need to be spaced out from the back of the tranny, i.e. having it welded onto the back?

The component pictured will fit on the back end of the ZF 5 speed but not the Getrag 6 speed.

[Turk]

so are we saying the back end of an e30/e34 gear box (below) will fit on the e34 v8 5 speed or maybe even the e39 m5 6spd?



Or will this need to be spaced out from the back of the tranny, i.e. having it welded onto the back?

[nando]

i wonder if the splined output flange on the E46 has the same # of teeth. The biggest problem with extended splines is removal of the shaft.

that's all well and good that some have 6 and BMW uses 3 - but I've NEVER seen a damaged BMW planetary gear. Unless perhaps the transfercase was run for a long time bone dry. the gears in my 275,000 mile case look brand new! remember, only 1/3 of the torque (approximately) is going through them.

[The Dark Side of Will]

this is a lubrication and maintenance issue. also, you can extend the splines at least another inch to give more contact area. BMW still uses this same basic design. The U-jointed transfercases still have that splined section, only there's a flange for the shaft to bolt to, instead of a one-peice shaft/spline.

And if it didn't experience torque, it would never wear...
That's exactly why I want to convert it to a fixed yoke front output.

why? have you EVER seen one damaged? they're basically the same size as the ones used in the diff, and transmission, and anywhere else in a BMW drivetrain.

They're small and narrow and there are only three of them. Six pinion planetary sets are pretty standard in high output two speed applications.