What: Custom Mapped ECU
Why: Originally, I started with Rocketchip ASV 110 Stage 2. Within a month, I realized I wanted more power, so upgraded to Rocketchip ASV 110 Stage 3. I drove on Stage 3 for about a year before deciding that I wanted to upgrade my power further. I added a FMIC and a VNT-17, which necessitated a new ECU mapping. To upgrade to a Stage 4 Rocketchip would be another couple hundred bucks. Since I have 4 cars to chip, I figured custom mappings would be better and cheaper in the long run.
Couple that with the fact that I could get mapping specifically tailored to my car and not have to ship my ECU off to Jeff at Rocketchip each time, it was really a no brainer. Jeff does superior work, and for one shot ECU upgrades, Rocketchip is really the way to go... that is if you can get ahold of him. He does a lot of work for racing/auto-cross and I presume other things, so he is often out of town or very busy. Contacting him via Email is exceptionally hard. The phone is less difficult... but trying to coordinate times to send in your ECU can be frustrating at times, with waits of up to 3 or 4 weeks before he can get to it.
I finally ended up going with Diesel Inside for the custom mapping work. They provided me with sockets to socket my ECU and a chip programmer, as well as technical assistance to get me started. Socketing the ECU is not a trivial task. I ended up buying an SMT rework station that uses hot air to desolder the Atmel chip in question... getting the chip off with hot air is no problem at all. Getting the socket onto the board is another matter entirely. The nozzles for SOP44 chips do not fit over the socket, and I haven't found a suitable nozzle that works for putting the socket back on without melting the socket itself, since it's made of plastic. I ended up socketing 5 of my ECUs by hand. This kind of buggered up the sockets base, but did not affect the socket itself and I am happy to report all the patients are doing fine.
Once socketed, the chips are really easy to replace/reprogram.
What I would do differently: The route I took was really the only reasonable route someone could take ... start out with someone giving you a canned map, in this case it was Rocketchip, that you can try out and see what you like and don't like. Then move on to custom mapping. If you have a lot of cars to do, or plan on doing it often, doing it yourself is the next logical step from that. If you plan on getting a map and then not messing with it ever again, RC or a single custom map is the way to go.
That said, I would possibly use an ODB-II ECU flash kit, instead of the socket/programmer route I took. I'm already too far down that road to go back, so I'll be sticking with the socket/programmer. I've heard the ODB-II flashing method can be problematic, but Jeff at Rocketchip uses it, and I've heard plenty of other people are using it without problems. I would definitely look into this route so you don't have to take the ECU out of your car and can do quick flashes whenever you want... even on the road with a laptop.
I purchased my kit from Diesel Inside.