I can get my blm at cruise about 128.But have read past topics on it and figured out how to do it.I just cant get a full explanation on the use of this.

 

many reasons to lock the blm.
I do it so I can be sure my fuel table is nera perfect and where it might need improvements. By locking the blm you can watch the o2 values and you can tell if it's running rich or lean from 14.7 afr.
Anther reason for locking is to watch the INT and to make sure everything else is working the way it should.
If the blm is locked (while everything is working properly) and the car isn't running right, hesitation, stalls, etc, then you might want to change your o2 sensor, check the IAC, all that jazz. It's just another trick in tuning and everybody uses it differently.

 

Is it any good at wot tuning?

 

Formula,

Probably the most expeditious way of tuning for WOT is on a dyno with a wideband O2 sensor. When you go into PE, the BLMs will lock onto 128, since you are now in Open Loop mode. And the AFR you are looking for at WOT is not 14.7:1.

 

I have to concur with ultimately using a WB O2 sensor for WOT. You CAN get your fuel tables quite accurate and then tune by "trial and error" using PE for best performance. But a WB helps dial you in much quicker. Also "tuning" on a dyno will also get you in the "ballpark" quicker. But ultimately, tuning for best performance (in the 1/4 mile) is what really counts - especially if you are quite "fanatical" as some of us are.

Bruce has some good insights into tuning (with and without a WB O2 sensor) and hopefully he will expand even more.

 

Glenn,

One thing I did was to run a scan of the dyno run using EASE.
With that I was able to correlate the voltage from the on-board O2 sensor to the AFR being displayed by the dyno's wideband O2.
At least this way I should be able to "ballpark" the AFR from changes to injector size, VE Tables etc. without having to go to the dyno to do it. Then when it looks like I am close, dyno the car for confirmation.

 

Sorry, but it just doesn't work that way.
The non WB O2 sensors are prone to output voltage changes relative to EGT. The second the ambient air changes or you make any timing or fuel corrrections, the EGT changes, and there goes you *correlated* numbers. The oem NB is a switching type, ie meant to be used as on and off, period. there is no two ways about it.

 

Bruce,

Thanks for the "heads up" on that. I realize that the on board O2 sensor isn't a tool to be used for tuning WOT. I was hoping to find a way of "estimating" AFR at WOT without having to go to a dyno every time I made a change.