S62 E30 AWD (Formerly: Fantastic V8 swap candidate)

[The Dark Side of Will]

Any pics of this car been posted yet?

Here it is in all its hideous glory:

Baltimore inner harbor, near Ft. McNair:
#potatocam

[The Dark Side of Will]

Of course part of the reason I'm going to this much trouble for the crossmember is so that I can make and sell a few.

Future projects I'd like to look into include an S54 swap crossmember that doesn't require oil pan mods and a rear subframe to swap E36/E46 rear suspension into an E30.

[The Dark Side of Will]

On a lark I looked up E34 engine mount arms, since that platform held the M20, M50 and M60 engines from the factory. I was expecting they'd be basically the same as E30 mount arms.

The engine mount locations appear to be much closer to the block than on E30's or E39's, by maybe as much as three inches. That *might* put them low enough that they sneak in under the steering shaft. I guess I have to grab a set of each now. They would certainly be easier to use than E53 mount arms, since they're in the same general location as the E30 RWD mounts.

[The Dark Side of Will]

I've had a saved search on eBay Europe for 2.35 and 2.47 BMW front diffs for liiiiiiiiiiiiiiiiiiiiiterally a few years now. They'd come up every now and then for 600-700 Euro, but mostly the E90 chassis version, which I don't think I can use. I already acquired an E46 2.47 front a while back, but had also snagged a 2.35 rear (188mm unit). The rear 2.35s & 2.47s are WAY more common. I paid more to ship mine than I did for the unit. An E46 2.35 front finally popped up recently in Vilnius, Lithuania for 200£... not sure why he priced it in £ instead of Euro, but whatevs. Shipping from the Baltics is always surprisingly cheap as well, so I jumped on it. It arrived yesterday.

So now I have the 2.35 front and rear gearsets. Yeah, that's really tall, but the 5 liter S62 makes more low RPM torque than the 6 liter LS2 and the E30 is a REALLY light car compared to an E39 M5--which I've heard also runs GREAT with 2.65 gears (210mm unit), so I think the taller gearing will work great with my application. Also, E30's use short tires.

I also have a Euro market E53 3.07 front diff. It appears actually to use the same case as the numerically higher ratios, so I that was an expensive piece of knowledge to gain.

My plan is to put the E46 2.35 gears into the E53 3.07 case with a Quaife for a Z3 1.9 in order to have the most expensive front diff ever installed into an AWD BMW.

Search string, since I actually had to read eBay's documentation to set it up:

Code: Select all

bmw (2.35,2.47) (vorder,vorderachsgetriebe,vorderachsegetriebe,front differential), Europa

And here is an article on boolean searching on eBay, since their documentation on it sucks donkey balls:

https://community.ebay.com/t5/Buying/Ho ... p/29941476

[The Dark Side of Will]

Just discovered that Euro market Land Rovers used the ZF S6-53 transmission that I want to use. They have a different rear housing than BMWs, so maybe there's an appropriate T-case that will fit that housing. LR's T-cases appear to be conventionally controlled and fairly compact, but also have low range. I'd rather not carry around the extra weight, but maybe I can tear it apart, weld some things inside, then leave a bunch of steel on the bench when I put it back together.

Jaguar XF's use the ATC-350 T-case that BMW used in the E90s... thought I was onto something there, but I guess not.

[The Dark Side of Will]

The 2.35 and 2.47 ratios noted above use a 188mm rear diff like the stock 6 cylinder E30's. The diff itself is strong enough for my app, but the 86mm CV joints the E30's used tend to start blowing up around 300 RWHP. The 94mm CV joints that E34's and "Big Six" cars used are much stronger. The 94mm output flanges plug right into any 188mm diff (except the viscous LSD originally used in the AWD E30), but adapting the outer ends is tougher.

I have a 2.93 210mm diff from a grey market E23 745i turbo. It bolts to the E30 subframe and with the E34 style rear cover and E36 M3 CSL diff mount bracket, bolts up to E36 diff mount locations as common retrofitted to E30's. Most cars using the 210mm diff also used 94mm CVs, except the E38 750 and E39 M5, which used 102mm CVs.

Being an overkillist, of course I wanted to use the 210mm diff, even though the 188 would be fine, and of course I want the 102mm CVs as well, even though the 94's, and probably even the 86's since the rear doesn't see full engine power, would be fine.

Even 2.93 is a lot of gear for this combo, so I originally was eyeing the 2.65 ratio, which is the tallest BMW ever built for their 210mm unit. The catch is that BMW never built a 2.65 gearset for the E46 or E53 front diffs. I think there's a 2.64 set for the later style front diffs, but they have laser welded crown wheels, which aren't fun to deal with.
I recently found out that E36 318TDS cars had 2.65 ratio 168mm rear ends. The front diffs are based on the 168mm rear diffs, but not identical. I think the rear diff pinions are longer. There's a Euro ebay seller who said he'd ask his tech guys about whether the RWD 168 gearset could fit the FWD diff. If it can, adapting a rear gearset to a front diff would hardly be the weirdest aspect of this build.

So now that I finally have the 2.35 front gears, I'm possibly choosing between the "tallest gears made" 2.35 ratio and the "unbreakable rear driveline" 2.65 ratio.

[The Dark Side of Will]

Another consideration is my plan B drivetrain... If I can't figure out how to get a controllable T-case to work with the S6-53BZ trans, then I have the option of reverting to the S5D-310/320Z trans as used in the E34 530i V8 cars with the T-case from an E34 525iX. The issue is that the 320Z is a 5 speed with 5th gear direct, so I'd need really tall diff gears to keep the RPM to something reasonable on the highway.

[The Dark Side of Will]

Also realized I can use the QuarterMaster generic flywheel I bought as an option for The Mule for Bad Idea so I don't have to try to get them to take it back 4 months later or let it sit on my shelf forever. Yay, recycling!