Reflash ECM for more power?

[chpthril]

All they would do to improve power is to increase timing (spark advance) and maybe lean out the air/fuel mixture a tad. Might pick up 10-20hp, which really won't be very noticeable at all. Not really worth it if you ask me. If you want more power, spend the $ for a Whipple charger and go crazy. Just be prepared to replace the shortblock when it grenades........



If they lean the tune slightly, you will actually see better fuel economy. They make the stock tunes pig rich strictly for engine safety. Rich = SAFE!!

Lower air/fuel mixture = cooler engine, more HP and lower fuel econ and higher fuel/air mixture = higher engine temp, lower HP and better fuel econ. You would be surprised how close the fuel map is to a street legal car. Most engines will/can benefit from a slightly richer mixture to increase HP. Cars have a target air/fuel ratio of 14.7:1, I'd bet if you could put one of these on a 5 gas, you would see about 13.5: to 14:1, maybe even closer to 14.7:1. You can only go so rich before performance begins to drop off.

We dyno'd a Nextel Cup car a few years back with a 5 gas in the tailpipe. If this race car had a catalytic converter, it would have passed the sniff test in most of the 50 states. So, it's all about having a complete burn, volumetric efficiency, and having the correct mixture.

[chpthril]

With the EEPROM ecm's in use these days, a re-flash and reprogram is the same thing.

Erasing a program and replacing it with a new program is "reprogramming". Scanning thru a program and changing lines of code is not really how it's done these days. A line of code may need to be replaced with 2 or many more lines creating "patches" which are messy. I had done both for many years working on the F-14. To me a re-flash is an erase/reload with the same program. An erase/reload with a new program is a reprogram.

If you have a 350 MAG MPI with the MEFI 3 (1999) or the MEFI 4 (2000+) it's neither. According to the guys at OBD Diagnostics the programming is generally the same in all the ECM modules, it's the data files that are changed to "reprogram". The MEFI 3 is an open-loop system and the MEFI 4 system is closed-loop with improved idle. The MEFI 3 is ECM 16236999 and on the charts is marked with an * Used by Mercruiser. What this really means is it's "locked" with a password by Mercruiser. The guys at OBD can't reload the data files without the password. I have another MEFI 3 module that was for the 350 Ramjet engines and is not locked. The guys at OBD say this module will probably work quite well as is, because they've seen the data files for the Merc version which are strange and tend to run rich.

http://www.obd2allinone.com/sc/toplevel.asp?cat=32

Not saying anyone's terminology is wrong, but I think we are kinda saying the same thing. A "re-flash" is the term I was taught in the early 90's by GM when PROM ECM's where on there way out and EEPROM where fast approaching. It is still used today, by them and most every other manufacturers, in their warranty labor codes.

[da.bell]

Reprogramming is when a computer program add's/edits/modifies the software to make changes. Updating/Upgrading is when that reprogrammed code is installed onto a computer running the previous version of the software.

So, Updating/Upgrading seems to be better like a reflashing of the ECM. Right????