24V AWD Swap Knowledge Base

[dama]

11-year lurker turned new 325ix’er. My car has a low oil pressure issue and to make my situation more complicated, I’m investing in 24v swaps.

Does anyone have images of the e53 pan/diff interference with the front subframe?

Secondly, is there anything gained from an early e53, M57 oil pan? The area around the right CV pass through does not take up the same internal volume like the M54 sump.

Instead, there are *only* some gussets to strengthen the diff and carrier mounts. If this was trimmed, could it work?

[dylhaus]

VAC motorsport shorty headers and Schmiedmann shorty headers fit with no modification

[dylhaus]

I'm starting a S50 24V swap on my 91 IX, just waiting for my frankenpan to come in from Classic Daily and documenting it here: https://www.r3vlimited.com/board/for...p-build-thread

I'm using the stock IX mount arms with sleeves welded in to accept the M8 mounting hardware so that I can retain the original transmission position.

Didn't end up using the sleeved mounts, bolts would likely break. M8 grade 12.9 is still weaker than M10 10.9, so I drilled and tapped the block where the original mounting points were. Engine mounts are attached to the engine and secured to the subframe

[dylhaus]

So you're running it at the 15 degree angle of the M20, instead of 20 degrees?

If that is the angle that the M20 typically sits at, yes lol

As long as I don't run into any surprises mounting the engine with the stock IX mounts, the swap appears pretty straightforward. I'm sort of stumped on whether the cheap ebay 24V swap headers for the regular E30 will have more or less clearance with the engine at 15* than 20 though.

[nando]

So you're running it at the 15 degree angle of the M20, instead of 20 degrees?

that's probably the easiest way. Maybe I'd actually have this done by now if I was willing to compromise, lol.

[dylhaus]

I'm starting a S50 24V swap on my 91 IX, just waiting for my frankenpan to come in from Classic Daily and documenting it here: https://www.r3vlimited.com/board/for...p-build-thread

I'm using the stock IX mount arms with sleeves welded in to accept the M8 mounting hardware so that I can retain the original transmission position.

[muuris]

Also, have you looked at this for transfer case control?

https://www.full-race.com/store/nissan/skyline-rb26-rb25-rb30/ets-pro-center-diff-torque-split-controller-for-r32-r33-r34-skyline-gt-r-1/

As long as the E34 T-case accepts a PWM input for the locking clutch, then generic center diff controllers for Subarus, Evos and Skylines will probably work.

A bit late answer, but I went for a different route and made my own controller :)

[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:

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/How-to-use-Boolean-operators-in-ebay-search/td-p/29941476

[The Dark Side of Will]

mw044 has ATC700 T-case and if I'm not mistaken, an Arduino-based controller for that..



I did M50 swap in my '86 iX this year with all-E34 stuff. So far haven't had control for center lock but I've designed and built my own Arduino-based controller for it. It gathers ABS sensor signals and will communicate with ECU. I've measured the center diff lock breaking torque is more than 200 Nm at under pwm 50 % duty so it's quite capable. What I'm unsure of is the how will the lock wear if used on the limit instead of fully driving it on/off. Ideally I'd like to allow just a bit of rear wheel slip and hold it there, but the safe way for sure would be to set a threshold after which the lock is ramped fully on and held there until TPS goes down and then ramp it down to 0 %.

I wanted to have permanent awd and just control the lock but if I would do this now, I'd really consider x-drive tc again.. The total driveline ratio is short (by starting point was 3.64 / G260) and 6-speed manual would make the already long package even longer.

The car is still very much in progress and not nearly finished, but this thread needs a picture once in a while so here it goes:



No, it won't stay n/a but the plenum is also there to clear brake reservoir. I swapped E34 525iX booster/mc as well, and it's tight with stock manifold/tb even though I moved the booster ~2cm away from the engine.

This thread and especially Nisse helped the swap a lot :)

Also, have you looked at this for transfer case control?

https://www.full-race.com/store/nissan/skyline-rb26-rb25-rb30/ets-pro-center-diff-torque-split-controller-for-r32-r33-r34-skyline-gt-r-1/

As long as the E34 T-case accepts a PWM input for the locking clutch, then generic center diff controllers for Subarus, Evos and Skylines will probably work.

[The Dark Side of Will]

mw044 has ATC700 T-case and if I'm not mistaken, an Arduino-based controller for that..



I did M50 swap in my '86 iX this year with all-E34 stuff. So far haven't had control for center lock but I've designed and built my own Arduino-based controller for it. It gathers ABS sensor signals and will communicate with ECU. I've measured the center diff lock breaking torque is more than 200 Nm at under pwm 50 % duty so it's quite capable. What I'm unsure of is the how will the lock wear if used on the limit instead of fully driving it on/off. Ideally I'd like to allow just a bit of rear wheel slip and hold it there, but the safe way for sure would be to set a threshold after which the lock is ramped fully on and held there until TPS goes down and then ramp it down to 0 %.

I wanted to have permanent awd and just control the lock but if I would do this now, I'd really consider x-drive tc again.. The total driveline ratio is short (by starting point was 3.64 / G260) and 6-speed manual would make the already long package even longer.

The car is still very much in progress and not nearly finished, but this thread needs a picture once in a while so here it goes:



No, it won't stay n/a but the plenum is also there to clear brake reservoir. I swapped E34 525iX booster/mc as well, and it's tight with stock manifold/tb even though I moved the booster ~2cm away from the engine.

This thread and especially Nisse helped the swap a lot :)

I think Nisse mentioned a controller that could do fully locked or fully open on the xDrive T-cases, but didn't have capabilities beyond that.

Have you tried hitting the E34 T-Case with 12V to see what the locking torque is? I @$$ume you measured that 200NM number measured by trying to twist the front output while holding the rear?

[nando]

It looks like he modified the firewall and pushed the engine back.

[The Dark Side of Will]

How'd you fit the oil sump and diff? Frankenpan?

[muuris]

You're right. I just remembered he used the original ix transfercase in that build. Bummer.

mw044 has ATC700 T-case and if I'm not mistaken, an Arduino-based controller for that..



I did M50 swap in my '86 iX this year with all-E34 stuff. So far haven't had control for center lock but I've designed and built my own Arduino-based controller for it. It gathers ABS sensor signals and will communicate with ECU. I've measured the center diff lock breaking torque is more than 200 Nm at under pwm 50 % duty so it's quite capable. What I'm unsure of is the how will the lock wear if used on the limit instead of fully driving it on/off. Ideally I'd like to allow just a bit of rear wheel slip and hold it there, but the safe way for sure would be to set a threshold after which the lock is ramped fully on and held there until TPS goes down and then ramp it down to 0 %.

I wanted to have permanent awd and just control the lock but if I would do this now, I'd really consider x-drive tc again.. The total driveline ratio is short (by starting point was 3.64 / G260) and 6-speed manual would make the already long package even longer.

The car is still very much in progress and not nearly finished, but this thread needs a picture once in a while so here it goes:



No, it won't stay n/a but the plenum is also there to clear brake reservoir. I swapped E34 525iX booster/mc as well, and it's tight with stock manifold/tb even though I moved the booster ~2cm away from the engine.

This thread and especially Nisse helped the swap a lot :)

[The Dark Side of Will]

Hacking through the ins and outs of using the ATC-700 or similar T-Case: http://www.corner-carvers.com/forums...ad.php?t=50342

The actuator is actually not a stepper motor. It's a DC motor with a Hall effect sensor to count revolutions. Many other "on demand" T-Cases use a similar motor arrangement.
HOWEVER, only BMW uses a worm gear drive that can not be back-driven by the load from the clutch mechanism.

In most applications, the controller PWMs the motor in order to control motor torque and thus clamp load. As the duty cycle goes up, the motor torque--and thus clamp load on the clutch--goes up. When duty cycle goes down, the motor torque goes down and the clutch relaxes, transferring less torque to the front driveshaft.
In a BMW, instead of just reducing PW and allowing the mechanism to the relax, because of the worm gear drive, the controller has to actively drive the motor the opposite direction in order to reduce front driveshaft torque.

That means that the center diff controllers on the market which output a PWM signal will not work with the BMW ATC series T-Cases.
Such aftermarket controllers could work with the E34 T-Case, however.

Example controller: https://www.full-race.com/store/niss...kyline-gt-r-1/

I may have to buy an ATC-700 to try it out, but a PWM-style motor may be adaptable to the ATC-700. There are T-Cases on the market that work pretty much EXACTLY the same as the ATC-700, but use a conventional PWM motor instead of BMW's weird setup.

[The Dark Side of Will]

Right... just need to know how many teeth per revolution.

GM actually did exactly that when they started using the F40 six speed manual from the Saab 9-3 in the Pontiac G6. The Saab used Bosch electronics and ECU got vehicle speed from the ABS/SC over the bus. The GM system in the Pontiac still needed a hardware VSS, so they just installed a reluctive sensor that read the final drive gear teeth directly.