bennyhonda7

im making my new map and was wondering if i should run closed loop or open loop? what are the benifits of these?

tranceminister

We'd need to know a bit more about what type of map your trying to create. Is it a boost map? An NA map? Basically closed loop is when your ecu takes signals and readings from the various sensors and attempts to achieve a stoichiometric mixture (14.7:1). This can be good in some cases and other cases it can get in the way and cause problems.
A good reason to use it is to improve gas mileage and achieve maximum powerout of your engine in closed loop. A downfall to having closed loop- enabled would be on an FI engine, and your cruising down the highway at partial throttle and your turbo begins to build boost. That means your ecu is trying to keep a stoich (14.7:1) mixture when you should be richening up to at least a 12.5:1 ratio.
So in order to compensate for the closed loop, we can disable it and run directly from our programed fuel/ignition maps. It will definately take quite a bit more tuning with closed loop disabled, but depending on what type of basemap your trying to make, and how your setup reacts at different throttle positions etc. , will be a good way to tell if you should disable it or not.

bennyhonda7

thanks its a FI map...just wanted to make sure before I did anything bad...Hey at least I look this crap up..and then when I cant find an answer at least I ask instead of going out and buying a POS FMU...

tranceminister

Very true, your trying to learn and do it right. And what better way to learn than the Homemadeturbo forums I'm such a kissass

TurboEF9

TM, you're a dork. :P

tranceminister

Happy to say your #2 to call me that on this site

juli0_bustamante

damm TM, now i dont feel so bad for not know what open and closed loop was. thank you!