LM-1 wideband effort
Thread Starter
TECH Apprentice
Joined: Jun 2002
Posts: 372
Likes: 0
From: Chester, VA
LM-1 wideband effort What's you guys opinion in making the effort to convert the car to run off the wideband 02 sensor instead of the factory ones? I know the PCM does not use it for WOT but... Ir seems like it "may" be worth it.
Thoughts?
Thoughts?
If your tuning is on the money, there is no reason to have a wideband O2 sensor installed in the car. If your tune up is good, then theoretically you can just run in open loop all the time.
Andrew
Andrew
The PCM wants a sensor with the switching characteristics
of the narrowband sensor. You might be able to fool it with
the right programming and output levels but I don't believe
there is anything to be gained by emulating a narrowband
with your WB unit.
of the narrowband sensor. You might be able to fool it with
the right programming and output levels but I don't believe
there is anything to be gained by emulating a narrowband
with your WB unit.
Originally Posted by jimmyblue
The PCM wants a sensor with the switching characteristics
of the narrowband sensor. You might be able to fool it with
the right programming and output levels but I don't believe
there is anything to be gained by emulating a narrowband
with your WB unit.
of the narrowband sensor. You might be able to fool it with
the right programming and output levels but I don't believe
there is anything to be gained by emulating a narrowband
with your WB unit.
So what are you saying a wideband sensor-system is no good. I understand that if your tune is on the money it would not be necessary. But on the other hand it would not hurt to know what your a/f is realy doing. Granted it will cost to monitor it but could save some major problems down the road.
At least with a standalone wideband you would know where you stand while in day to day driving conditions.
I have heard the that normal a/f gauge systems are not all that correct, bounce all over the place-light show.
dont take me wrong I am open for any creative input.
Last edited by 618HAWK; Dec 29, 2004 at 11:23 PM.
No, I'm saying that for the GM PCM to operate as designed
you want the narrowband type of response in a switching
mode.
If it was a linear, real-time type of control loop a wideband
would be better, but that is not the case at hand.
The wideband meter is useful for non-stoich tuning and
I have one. But, it is out-of-place in the application DD
described (substituting for the narrowband type that the
stock PCM expects). You could probably fake the wideband
into looking like a narrowband but that's about $300 worth
of pointless.
you want the narrowband type of response in a switching
mode.
If it was a linear, real-time type of control loop a wideband
would be better, but that is not the case at hand.
The wideband meter is useful for non-stoich tuning and
I have one. But, it is out-of-place in the application DD
described (substituting for the narrowband type that the
stock PCM expects). You could probably fake the wideband
into looking like a narrowband but that's about $300 worth
of pointless.
TECH Regular
Joined: Mar 2002
Posts: 433
Likes: 0
It should be possible to emulate stoich switching at some other than 14.7 afr. I'm not sure if LM-1 can do this but technically it is well feasible and could be useful, if you want to run closed loop for some target afr...
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You can set the transfer function pretty arbitrarily, and if
you made the transfer function very steep but offset to the
target AFR, made the range 0-1V and eliminated the "smoothing",
then it might be fast enough to play well. The LM-1 has two
separate outputs so you could have one faked this way and
the other set up for logging (nice, slow and linear).
you made the transfer function very steep but offset to the
target AFR, made the range 0-1V and eliminated the "smoothing",
then it might be fast enough to play well. The LM-1 has two
separate outputs so you could have one faked this way and
the other set up for logging (nice, slow and linear).
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Originally Posted by jimmyblue
No, I'm saying that for the GM PCM to operate as designed
you want the narrowband type of response in a switching
mode.
If it was a linear, real-time type of control loop a wideband
would be better, but that is not the case at hand.
The wideband meter is useful for non-stoich tuning and
I have one. But, it is out-of-place in the application DD
described (substituting for the narrowband type that the
stock PCM expects). You could probably fake the wideband
into looking like a narrowband but that's about $300 worth
of pointless.
you want the narrowband type of response in a switching
mode.
If it was a linear, real-time type of control loop a wideband
would be better, but that is not the case at hand.
The wideband meter is useful for non-stoich tuning and
I have one. But, it is out-of-place in the application DD
described (substituting for the narrowband type that the
stock PCM expects). You could probably fake the wideband
into looking like a narrowband but that's about $300 worth
of pointless.
Staging Lane
Joined: Jul 2002
Posts: 57
Likes: 0
From: Ohio
So what are you saying a wideband sensor-system is no good. I understand that if your tune is on the money it would not be necessary.
I see hesitation from many over installing an additional sensor bung; but I can't figure out why ??? My local muffler shop installed one for me - for $15; complete with cover and all.
I install my LM-1 sensor, make some runs, make tuning changes, verify changes with a few more runs... then I'm done with it. I remove the WB sensor, instal the cover and put the LM-1 away until I make changes under the hood again.
Ditto, My car has wideband bungs on both sides of the Y pipe for tuning.
Cost, $5 for the 2 18mm plugs, and nuts, and about 1 hour of time, to pull the Y and have my friend weld them on.
Ryan
Cost, $5 for the 2 18mm plugs, and nuts, and about 1 hour of time, to pull the Y and have my friend weld them on.
Ryan
