Im wondering, what do they mean by "closed loop"? Do you guys like them or is a cheaper item just as beneficial?

 

When running in closed loop, it is using the A/F signal from the 02 sensor to regulate the mixture. There is a feedback "loop" between the sensor and ECU so the ECU continuously makes adjustments based on the 02 data.
In open loop the 02 sensor isn't used and the ECU sets mixture based on stored maps and other sensors. Get it. It's simple and easy to use.

 

Right on, thanks for the easy explanation, appreciate it. Can i expect immediate HP gains, or will this cause more of a stable ride and prevent mapping at the dealership when i change pipes and filters and what not?

 

If you buy the tmax the dealer will no longer be needed in that aspect.

 

I am going to buy some kind og fuel mgmt and exhaust upon came upon this thread. Where do folks buy Thundermax.

Wheelup...if you know of the top of your head which fuel mgmt uses open loop? (I am referring to those PV, PCIII, Thundermax and likly others). From reading the threads I do not think all fuel management systems uses open loop which is why some call these piggy back systems.

 

i bought my thundermax w/ auto tune off ebay for a great deal------$430

 

Even the stock system is OPEN LOOP in some MODES!
P.E. (Power enrichment being the most obvious!)
And closed loop is a system of fuel control where the O2 sensor signal is DRIVEN rich and lean. It is a small difference in the explaination givenm above, but an important difference. The fuel control adds or subtract small amount of fuel to DRIVE the sensor from rich to len and lean to rich! And even though OPEN LOOP does not use feedback from the sensors, it is also improtant to understand that there are "FUEL CELLS" where the correction is stored, and even in OPEN LOOP the correction from a "CELL" near the OPEN LOOP cell, can be used to adjust fuel in OPEN LOOP.
Most normally, the OPEN LOOP fueling will allow the "learned cell" value to adjust RICH but not subtract fuel
"LEAN" in open loop.
Add on devices work in many different ways. The PCIII type devices have a seperate CELL structure that allows additional fuel (BY the device CELL break points) to enrichen from stoich. They will also allow additional fuel in open loop. So when a "tune" is done, it is VERY IMPORTANT the tech knows what he is doing. The stock ECM can and does have "MODES" that also add and subtract fuel based on TEMPERATURES, (intake and engine, engine temp, is model based!) and time at SPEED AND LOAD. So if a tech doesn't understand when the ECM software may be in an "abnormal mode"(easy to do on a dyno setting while tuning a "set point") you can get a bad tune when the ECM software is back in normal operation!
Also some of the "O2 Biasing" devices (they skew the voltage reading to the ECM to try and achieve a richer A/F) can be somewhat affective during "CLOSED LOOP" and have less correction during open loop.
O2 biasing devices on newer bikes also risks setting Check engine lights as O2 voltages are used for diagnostics!!