The stock O2 sensors are like Chevettes and the sensors the TMAX uses are like Corvettes. They both do the same things, basically, but the capabilities and ranges over which they do them are different altogether.

 

The stock O2 sensor is a "narrow" band type,around2,000 rpmthere not doing anything, the TMAXsensor is a wide bandtype good to however tight you want to twist the wick. If you have the money get the TMAX from Shooter64 on this site.

 

Check out this link for a nice sniipet about O2 sensors (look at the sidebar on the right, down a bit). Their usefulness doesn't really have anything to do with RPM, it's the AFR they can operate in.
http://www.fordmuscle.com/archives/2...vate/index.php

 

Their usefulness does have to do with RPM insofar as the ECU's programming is concerned. I believe 2000 RPM is well within the range the Delphi consults them, at least while at part throttle.

 

Because the stock O2 sensors are narrow band 2 wire sensors. They only read 14:1 to 15:1 roughly. The T-max uses a 5 wire wideband sensor that reads a mixture from 10:1 to 20:1. This allows closed loop operation throughout the map.

 

I know it may come as a surprise, but the stock ECU also has limited autotuning. It checks for error against the VE tables while in closed loop and modifies a factor it uses everywhere. So even if the result ends up out of range of the narrow-band sensors it will dial it back in. It's not nearly as capable as autotuning everywhere but it ain't a toy, either.

 

Makes you wonder why HD didn't spend a couple more dollarsfor a better ECM and save us all the trouble and money but then these are the same people that screwed us 07 owners by making us buy the IDS.

 

Nobody's making anybody buy anything. They can't make a user-adjustable ECU for use on an EPA regulated gasoline-powered anything.

 

Anyone understand what the LC1-standalone wideband controller/kit differs from the tuners we have been discussing? Is this a piggyback system that makes adjustments based on the output of stock ECM?

 

This is a wide-band sensor with controlling/driving electronics. Which the sensor needs and our ECU doesn't have. It has a couple of outputs, one of which will mimic a narrow-band sensor (which we have/use). Normally the narrow-band sensor has a mid-point in its voltage output of just under 0.5 VDC, which corresponds to 14.7:1 air:fuel ratio. The "narrow-band" output of the LC-1 can be adjusted to a different mid-point so it would be possible to make the ECU inject more fuel to get to where it thinks it's at 14.7:1 but is actually somewhere else.

There are a couple of downsides to this approach, however. Actually three when cost is considered. The two primary ones are that for the '07+ you'd need to buy two of them. And that the ECU has been programmed to think it needs to spray so much fuel under a given circumstance. If that given is during closed-loop operation (much of what occurs during a normal ride) the ECU will get the fuel up to where it needs to be according to the sensor feedback. It compares the amount of fuel it needed to the amount it thought it did and modifies a multiplication variable up to ±15%. It uses this variable as the final factor in determining how much to spray for every condition (including open-loop operation: WOT, for one). If you don't get into the ECU with a SERT and set the baseline variables to appropriate values you'll be running way rich up top if you richen the mix with the output of the LC-1.

There might be a way to fudge things with the SERT so it works well everywhere, but then you're at or above the cost of a TMAX or DTT which don't require all the shenanigans.