S52 OBDII swap questions- help much appreciated! (long)

[SportAuto]

Hey guys, I'm new to the forums but a life long BMW nut. I work for German Auto in San Luis Obispo, CA and I'm in the process of swapping a '98 S52 into a friend's '98 Ti, with the goal of full legality and OBDII compliance. Basically he spun the #3 main bearing in the old M44 at 120k miles and has the car set up far beyond that engine's capabilities anyway, so it's time to step up I have a complete S52 with all accessories, a JBR LTW flywheel from Turner, a complete engine harness, M3 airbox/MAFS, M Roadster rear diff, M3 exhaust, and an M3 instrument cluster. He's opted to wait on the M3 gearbox and M Roadster subframe for the time being, though I've already told him he'll want them as soon as I take him to the track with it. I've already searched through previous threads and talked to about every listed vendor/shop/source mentioned, but can't find anyone who has actually done a fully certified, turnkey, no questions asked OBDII compliant swap that will pass muster with a CA smog referee. Does anyone have any information in this regard? I've already heard about the "instruction manual" but that's for an OBD1 swap, correct? I'm currently working on the wiring interface, which after comparing ECU pin-out diagrams/wire colors at the engine compartment gang plugs and instrument clusters appears to be relatively straightforward (thankfully!) Basically I want to know if I'm not alone here! I'd be more than happy to offer my input/assistance to anyone else once this beast is complete- I'm doing my best to document everything I'm doing in pictures and writing, so hopefully I'll have those for you guys before too long. I'm scheduled to work on this project all week, so theoretically it'll be done by the weekend Just to give you a visual, the car is an Avus blue '98 Ti w/ gray interior, California package, lowered about 1" with Turner coilovers, on 17" Anthracite/polished lip SSR comps. I love the car- every time I drive it I want a Ti- you guys definitely know what's up. As far as the old M44, I'll be going through it, making a couple of upgrades, and putting it in my red '68 2002 with TWM induction and standalone Thanks soooo much for any info or assistance you can provide!!

Tucker Fritch
SLO, CA

[cali-ti]

would definitely be interested in the info when you're done. i believe J!m did an OBDII swap (also has the M coupe rear subframe/diff/trailing arms/brakes) and that he is the one to put together "the manual." there was a recent thread by Dredder (who was doing an OBDI swap into his 95 ti) that he responded to and i'm pretty sure he mentioned his manual covered the OBDII so everything might not match up for the OBDI. you might want to check with J!m directly.

[1996 328ti]

On my conversion there were CEL issues.
Secondary Air pump
Previous owner did not have them installed probably because they would normally fo where the battery is.
Exhaust flap. The car doesn't have one.
Fuel pressure sensor. The ti doesn't have one.
CEL bulb failure. I had the light removed.

Eventually I had the fault codes written out of the software so I can have a functioning CEL. Besides, I wouldn't have gotten through emissions with a lit CEL.

[SportAuto]

Thanks guys, I've emailed Jim re: the manual, but I'm already coming together so a couple more q's here... it is a project, after all, and no amount of research prepares you for everything. With the engine and trans in now, it's apparent that the shift linkage and driveshaft will require shortening. This is with the stock Ti trans and an M Coupe rear diff-there was conflicting info regarding whether this was required or not. It appears that the shift tower and rod will need to be cut by about 3/4 inch, with maybe an inch on from D/S to allow full articulation. Also, the stock CV joints won't work with the M diff, as the CV diameter is off by close to an inch- 3.8" to 4.4. Apparently earlier M3's had 27mm axle shafts (same as Ti)with the larger CV's, as opposed to the later 38mm axles, so I'm going to try to mix and match the joints on the M3 axles I have with the 318 shafts. The 318 flanges fit into the diff and seem to engage the lock ring, but they are notably shorter and I'm not comfortable with such a small contact area with the internal diff splines. The wiring is proving to be straightforward- of course it's nice to have complete pinout diagrams of both the 318 and M3 harness side by side, as well as ETKA. I'll keep ya posted, thanks for the input!

Tucker Fritch
SLO, CA

[cali-ti]

so you only have the diff from the m coupe and not the complete rear subframe/trailing arms/brakes/etc? ugh ... i would see if you could source it all from the m coupe (including half shafts) ... this is what J!m did. i'd hate to see you cobble something together like you're describing with part m coupe and part 318ti half shafts. how about e30 halfshafts? those fit the stock ti trailing arms/hubs and possible would bolt right up to the stock m coupe diff flanges.

pretty sure i remember J!m mentioning the shift linkage in the thread dredder started, but i'm not sure about the driveshaft, i'll go see if i kind find that thread quick and post the link to it if i find it.

[cali-ti]

finally found the thread i was looking for ...

http://www.318ti.org/forum/showthread.php?t=5505

[SportAuto]

I tried and failed to find any M rear subframes. My main used BMW part source wondered why they go so fast I'm pretty sure I saw the shifter thread- Dredder apparently bolted his right up to an S50, but Jim's required modding with an S52. This doesn't make sense because the external block dimensions are unchanged, and as far as I know the motor mount brackets are the same. The M diff bolts right in to the stock subframe, and I may just make an adjustable short shifter out of the stock stuff- we'll see. I'm mostly curious about the discrepancy in driveshaft info? None of my vendors sell individual new CV joints for BMW's, only whole axles, so that's why I'm investigating my options there. I do have access to an E30 parts car so I could try those axles, but that doesn't solve my basic problem with flange incompatibility. Thanks for the help Cali!

Tucker
SLO, CA

[cali-ti]

it would if the e30 halfshafts have the same pattern as the m coupe diff flanges ... let me see if i can find something else that may shed light. one moment ...

http://www.bimmerfest.com/forums/showthread.php?t=43310

ok, this guy swapped an e30 3.73 LSD into his m coupe (sort of the opposite of what you're doing if you use the e30 halfshafts). he moved the m coupe diff flanges to the e30 diff so, if the e30 halfshafts don't bolt directly up to the m coupe diff flanges, you should be able to do the opposite and swap the e30 diff flanges into the m coupe diff, right? so you'd have e30 halfshafts, e30 diff flanges and the m coupe diff. you may need to shim the ABS sensors in the ti hubs to gain proper clearance. remove them before installing the e30 halfshafts and then check clearance once you have the halfshaft in place in the hub.

sounded like the shifter/driveshaft issues were because of what J!m selected to use - check that part of the thread again, i'm already forgetting (need to eat dinner and get my blood sugar back up ).

[cali-ti]

and check with this guy to see if he still has the m coupe rear end (minus diff, lol) still available! http://www.318ti.org/forum/showthread.php?t=5534

hook it up!

[Dredder]

If you using the stock 318ti tranny you do not need to modify the shift linkage. I verified that with my mechanic the other day when i had him check the 2001 mroadster rear brake setup i purchased. By the way the brake does not fit all all.
If you are going with the mcoupe differential, i suggest you get the compete rear subframe.

[SportAuto]

That's impossible in this case because the hole for the locating pin in the shift tower is approx. 1/2" forward of where the bore in the trans now sits. I can use the stock rear trans mount, but it's now moved back 1/2 inch so I have to use the other set of slotted holes. There's not enough play to just pull the tower back, and if there was the shifter would be in the wrong place. Do you know if perhaps your S50 engine mount brackets are slightly different? Also, the oil pan rubs the p/s cooler line bolted to the rack, and this is with new OE motor mounts. No big deal there, just something else to address. Thanks again for all the input guys.

Tucker
SLO, CA

[jcarp]

Here are two people you can contact that had M Roadster subframes minus the diff,

David Herpolsheimer <davidherpolsheimer@mac.com>

Alex <eurospeed@mindspring.com>