Originally posted by KennyTheGreat
someone told me u could convert ODB2 to ODB1 again for a couple bills
is this true?
Although I would debate the "couple bills" part of the statement,
it is true that you can convert the OBD2 setup to OBD1 spec by changing sevaral key components (mainly engine/fuel management). This is the setup I've been running on my car for a year and a half with no problems whatsoever.
Basically to do the conversion you will need the following:
1) OBD1 wiring harness and ECU (preferably from a 95 M3). You can use a 325 harness and ECU (93-95 w/vanos) but you will have to get software that's made for a 95 M3.
The ECU will have to be the "413" unit which is common to both later production 95 M3's and 325's (of course w/different software). You can also use the "506" ECU which was mainly used in the earlier production 95 M3's.
2) You will need the OBD1 intake runners from a 325 or 95 M3.
3) Also required is the fuel rail out of a OBD1 325 or 95 M3. You can use the 21 lb/hr injectors from the 3.2 engine on the donor rail .. however you will obviously need the software to take advantage of this. You can also opt to stick with the 17.5 lb/hr injectors that come standard on 95 M3's.
4) OBD1 HFM out of a 325 or 95 M3. These parts are common to both cars and share the same part number. A common upgrade (which I have done) is to use the Euro-HFM. This unit is 3.5" in diameter as opposed to 3" for standard. Mated to the correct software and injectors substantial gains can be seen on the dyno.
Turner, Jim Conforti/Eurosport, Active Autowerke all have these kits.
5) A tap or two (can't remember) will need to be drilled into the 3.2's head. This is to facilitate an extra sensor/s from the OBD1 electonics.
Dave at Motronix did the work in a weekend !! I got to help somewhat and learnt a lot by watching him and getting my hands a little dirty.