I'm putting an S52 into my 93 325i, I've searched a lot of threads and seem to know what I'm getting in to, just had a few questions I wanted to confirm. I will be getting the entire harness and ECU as well as tranny and driveshaft with the motor. It has 94K on it.

1. If I wanted to leave it OBDII I would just use the harness and ECU from the new motor, right?
2. If I leave it OBDII I will have to disconnect the EWS system, correct? I can buy a chip to eliminate EWS, correct?
3. If I leave it OBDII I can still swap the M50 manifold for upper rpm gains, correct?
4. If I change to OBDI I would use the harness and ECU from my original engine? And I would have to swap a lot of stuff on the motor itself to make it OBDI.
5. What is the advantage of going OBDI? I've heard the tuning advantage is no longer there with the newer OBDII tuning methods. This will be a racecar, so A/C and emissions is not necessarily an issue.
6. Will I have check-engine lights with either method - OBDI or OBDII?

Thanks for the help.

hey man........you need to talk to Kyle or Bob of the Mofo's they would be to able to answer all your questions...plus might be able to help you out on some things......I am going to be doing the same thing ...so you should do a detail write up with pics so ...it would be easier on me..lol......since we will similar setups....

you might also post your question in the Southwestern section....so the other Mofo's can help you out....

I talk to Kyle and for our '93 its a pretty much drop in.....just minor things to fix and workout....its not as hard as putting an S52 in a...Ti....plus with our OBD I set up it makes the conversion even easier.....

Kyle, Jed, and a few other Mofo's are going to BMWCCA Autocross at the Sheriff's Training Facility on 36th and Air Depot this Saturday.....they should be racing their cars too....

You want to convert the s52 to OBD-I for better tuning possibilities. Use the m50 intake mani and you're also going to need to reroute some vacuum lines to accommodate that year manifold. Because its going to be OBD-I, you'll need an OBD-I computer and altered via a chip so the DME doesnt look for the EWS box etc..This dude is mentioning Mofo's, not sure what that is, but you can buy all the conversion parts and the shop I work at can sell you a chip to make it happen. Just let us know the mods and stuff and I believe we can burn you a chip for your needs. Contact Jon Siccardi at TreehouseRacing.com. His call number is on the site. We pretty much specialize in these swaps and Jon is a known member of NASA/SCCA and BMWCCA Club events. He will be able to guide you in the right direction.