24V AWD Swap Knowledge Base

[Eskie]

Sorry... I never followed up on this. I received the shaft and it looks... machinable? The spline size certainly is MUCH beefier than the spline size on the stock E30 unit.

I'm not sure what I'll do with it yet. I think the S6S-53BZ is a great option for a transmission, but it'll take some work. I'll have to add a crank sensor boss to the bellhousing to run the S62. I'll have to make a shift arm and shift rod/DSSR. I'm still up in the air about the T-case... whether that's a E30 A95, E34 A110, BW 4472, ATC-700... Or just call up Quaife and see what they say.

Maybe I'll go with an Atlas 4 speed.

My goal is to be able to run stuff that is relatively cheap to replace and can take a punishing. E30ix parts are getting hard to source and I want to be able to go to the drag strip or autocross without worrying about breaking something. Or at lease worry about breaking something that is super hard to find. I'd like to run a M50/M52 turbo with a manual trans like S6S-53BZ or even a dual clutch auto. A front diff from anything newer because they are plentiful and I really haven't seen any failures yet, even in heavy X5M's. The ATC-700 would be nice to run for a transfer case because they are easy to source and if you built a controller you could set the bias between RWD and AWD. That would be a great option for people that daily drive their ix's like I do.

[The Dark Side of Will]

Do you want me to mail you the shaft? I can next week when I get back to work

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Sorry... I never followed up on this. I received the shaft and it looks... machinable? The spline size certainly is MUCH beefier than the spline size on the stock E30 unit.

I'm not sure what I'll do with it yet. I think the S6S-53BZ is a great option for a transmission, but it'll take some work. I'll have to add a crank sensor boss to the bellhousing to run the S62. I'll have to make a shift arm and shift rod/DSSR. I'm still up in the air about the T-case... whether that's a E30 A95, E34 A110, BW 4472, ATC-700... Or just call up Quaife and see what they say.

Maybe I'll go with an Atlas 4 speed.

[The Dark Side of Will]

Grabbed a set of E34 M20 mount arms from eBay... I should be able to give them a shot in three weeks, since they probably won't arrive before next weekend and I'll be at drill the weekend after that.

[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]

e36 are used for 24v RWD swaps, not e46 (that I am aware of, anyways). Even the s54 uses e36 arms.

Thanks! Didn't know if they were functionally interchangeable for this purpose.

[ForcedFirebird]

e36 are used for 24v RWD swaps, not e46 (that I am aware of, anyways). Even the s54 uses e36 arms.

[The Dark Side of Will]

So, the basic RWD 24V engine swap uses E36 mount arms to mount at the E30 RWD mount locations, right?
The M54 has the same mount pattern as the M50 & M52, right? And the E46 mount arms work as well?

From the information I have now, I will need to do the following:
Buy E36/E46 RWD mount arms.
Buy E53 6 cylinder mount arms.

Have the CMM guy build a report for each one that will show me where the mount pad locations are relative to the bolt pattern on the block.
Are those the right mount arms to select for that method?

Since I have the E30 RWD locations on the crossmember now, I should "just" be able to add E53 mount locations by using the location of the mount pad on the E53 mount arm relative to the location of the mount pad on the E36 mount arm, with both referenced to the block bolt pattern.

The con for using the E53 mount arms is that the E53 mount mounts to a flange on the body side and an angled stud on the mount arm side. The stud is NOT perpendicular to the mount flange. The E53 mount is ~$115 each. I *can* set the crossmember up to use a "normal" mount at the E53 angle... that just adds yet another level of complexity.

What's the "normal" 24V swap engine mount?

[The Dark Side of Will]

With the E30 rack in its original orientation, the steering shaft will probably go through the left RWD mount arm. As I investigate this packaging, it becomes more obvious why BMW moved the engine mounts. Clearance to the left one was probably the driving factor. On the E30, they pushed the left mount forward of the RWD position. On the E34 they pulled it back. On both of those platforms, BMW then arranged the mounts symmetrically, matching the right side where they had to put it on the left side.

However, on the E53 X5, BMW staggered the mounts. The right mount is forward, the left mount is to the rear. The left mount is moved back to drop under the steering shaft as on the E34, but the right mount is moved forward to clear the axle and six cylinder exhaust like on the E30.

I'm starting to think that I should be looking at E53 mount arms. I had initially rejected that idea because using those arms would require developing a lot more structure for the crossmember due to the left mount being behind the axle. If the options are to use E53 mounts for a bolt-in swap or modify the steering rack for EVERY swap, using E53 mounts sounds like a better option. Also, it only requires adding structure on one side of the engine bay. The added structure can be an additional piece which bolts on the to crossmember and picks up the lollipop bushing mount, which is a nice strong hard point on the body. I just hope the E53 mounts aren't so wide that they interfere with the E30 frame rails.

[The Dark Side of Will]

Was able to get RWD engine mount arm data into a usable form.

This still requires gussets to support the RWD mount locations, but it's a solid start.
I'm getting to the point at which I'll have to add the ball joint blocks on the back sides of the rear transverse vertical bulkheads to make sure that the RWD mount plate gussets fit around them.

[The Dark Side of Will]

If it's not any problem, that would be super handy. Thanks!

[Eskie]

Do you want me to mail you the shaft? I can next week when I get back to work


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[The Dark Side of Will]

I have been thinking that I might need to take an ATC-350/700 input shaft and cut off the female splines that mate to the output shaft of an GS6-53BZ so that I can use those splines as the basis for a shaft coupler to install whatever T-case I want.

[Eskie]

WOuld be interesting and there are some guys here who have used the ATC... but you may not have it anymore at this point
I think it's pretty awesome that the ATC 700 bolts in place of the ATC 350.

I still have it, it’s in a box under my desk


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[The Dark Side of Will]

I'll need to pull the airbox and AFM to get a better look, but it looks like the RWD mount arms will interfere with the AWD steering shaft, but probably not the rack itself.

I already knew that the spool valve on the iX rack would interfere with the E53 front diff and had figured out a candidate method for rotating the rack. Rotating the rack will require an "exotic" 3 or 4 joint steering shaft geometry, but that's nothing new in the hot rodding world. It'll just have to reach over the RWD mount arm. I was hoping that only E53 based swaps would need to rotate the rack, but maybe they all will. Feh.

[The Dark Side of Will]

WOuld be interesting and there are some guys here who have used the ATC... but you may not have it anymore at this point
I think it's pretty awesome that the ATC 700 bolts in place of the ATC 350.