how can I tell if the DME I have will work with the engine/transmission I am thinking of buying? The one for the motor is a MSS54HP and the one I am looking at getting is a MSS54. thanks

you really need the part numbers off of the DME's. Then you could probably call a dealership parts department and they could run a part number cross check to see if one number changed to the other, if so, they're the same part.

keep in mind IF the DME's are even capable of being swapped from one vehicle to another (which I'm not sure if they are), the DME will still have to be aligned with the EWS before the car will start.

we are looking at doing a M3 motor and transmission for a hot rod. What is EWS?

found out what it is. i didn't know that was what they called their immobilizer system.

screw the stock DME if the S54 isnt going to be in an E46 M3.

The only reason to run a stock DME is if you want it to control the rest of the cars functions as well... That being said, you cant tune the stock DME so dont expect much of a hot rod.

Now since thats taken care of you need to find a good standalone engine management system for your setup.

There are a few obstacles however, actually... there is only one... Dual Vanos.

There are only a handful of standalones that can handle BMW's Dual Vanos system. Motec M800, AEM (with a proper code written for the trigger wheels), Pectel, and Autronic are the ones I know of that can handle the S54 in all its glory.

The Motec and Pectel are top of the line and expensive... The Autronic has minimal US support but is more reasonably priced. The AEM is probably your best choice and is also reasonably priced. It can be had for around $2K.

Now if you feel the vanos is getting in your way, you can install the VANOS block off system which removes the variable timing adjustment system from the camshafts. The block off plate sits where the vanos unit used to, and allows the cams to spin at one timing setting. This technique is used by many M3 race teams as the vanos can be seen as a possible failure point during a race. it was initially done because the first M3 race teams using the S54 could not find a standalone capable of properly handling the Dual vanos system and taking full advantage of it. In addition Vanos tuning takes forever and a day... tune the intake cam over 60 degrees of range for load points throughout the rpm band and airflow tables, then do the same for exhaust, and then perfect cam overlap.

If that kind of tuning is not something you want to get into, I would recommend the VAC Motorsports vanos block off kit. Couple that with a larger number of standalone options and tuning should be easy.

Also, without vanos you will want to throw in a super hot cam.

Good Luck!

wow, pretty informative.

EWS is the electronic immobilizer. There is a ring antenna that reads the chip inside the key. The EWS says, "Okay, that key matches this car" and sends a signal to the DME to allow the engine to start.