the software upgrade is a biproduct of the CAI. I am told without the software the engine will run to lean; triggering the check engine light.
false. the engine will not run lean because the ECU will compensate for it based on the amount of air passing through the MAS as well as the signal coming from the O2 sensor (which measures the difference in oxygen content between the exhaust gasses and the outside air).
actually, there is some truth to the story in that when a CAI is installed (only) Dinan stage-I software and the OEM software will trigger a fault code. even then it's a rare occurance that will happen under extreme conditions. I heard from a VERY reliable source, that the diffrence in the software involves fixing a *factory* miscalibration of the catalyst overheat protection system that is only triggered with a CAI. only Dinan does this (forces you to upgrade - albeit at no charge- when you buy a CAI). all other vendors of BMW software to my knowledge compensate for this in their one and only version of the software. I suppose Dinan has their reasons for doing this along with their reasons to not muck with the VANOS via software for non-supercharged cars (per their software engineer).
Originally posted by Tanin
I was also under the impression that attempts to make more HP have been unsuccessful with all aftermarket manuf. (?)
false. the tuners that *are* making HP (at least three that I know of - more like everyone BUT Dinan) are fooling around with the VANOS (changing the cam timing electronically via software).
I have personally answered these two questions numerous times on several bulletin boards. :banghead: a search of the archives might yield even more info.