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LM-1 and gauge

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Old 11-08-2005, 06:02 AM
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Default LM-1 and gauge

Lately, I've been using the LM-1, and recently purchased a digital gauge from Dynotune the splices into the output wires on the LM-1. If I understand correctly from Innovate's user manual, one of the outputs is already programmed to read out the proper a/f ratio. However, it is reading around .5 point different than the lcd readout on the box. Am I doing this right, or do I need to program the other output, too?
Old 11-08-2005, 10:50 AM
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Is the gauge setup to read 0-1 volts of 0-5 volts? you need to find out what voltage the gauge expects, then use the innovate software to connect to your LM1 to make sure it's outputting the proper voltage range
Old 11-08-2005, 12:10 PM
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Potentially the issue is one of potential voltage offset between what the LM1 box is putting out (or thinks it is putting out) and the voltage that the gauge reads.

I saw a small offset from what my LM1 was putting out and what the software was reading, so I made an adjustment to the formula.

I set up the LM1 to output the same voltage regardless of AFR, basically you put the same # in the voltage box at both positions for the wideband channel. I did this 5 times, in steps of 1.0 volts - .5, 1.5, 2.5, etc. I then started the car and logged the voltage that was reading. It was off by a little bit, not much really, but I would rev the engine in the garage a little during logging just to make sure any alternator voltage effects were taken into account. I really did not see output voltage vary more than .1-.2 volts.

Anyway, then I made this little excel table that I used to derive a new wideband equation for. The function in Excel is LINEST.

Basically all it does is use the measured voltage and derive a new slope and intercept so that the AFR matches what the LM1 is trying to tell it. On mine, I measured less than .05 error, so although it didn't really need correcting once I had the formula I used it anyway

Hope this helps ! See attached file !
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lm1 output analysis.zip (2.0 KB, 14 views)
Old 11-08-2005, 03:35 PM
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Thanks! I'll give it a whirl.
Old 11-08-2005, 03:38 PM
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Actually, the gauge needs to be set up with 1.00v=10:1 A/F; and 2.00v=20:1 A/F. But it looks like it needs to be tweaked from those numbers just a little.
Old 11-08-2005, 03:46 PM
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Let us know how it works out !
Old 11-08-2005, 03:50 PM
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I'm going to program it tonight. Then, it really needs to sit overnight before I calibrate the LM-1 again.
Old 11-09-2005, 11:12 AM
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You need to program one of your outputs to be
1.00v=10.00
2.00v=20.00

The DynoTune gauge needs an input of 1-2V not the 0-1v or 0-5v that is pre-configured as from innovate. Call us if you have qestions tonight at 1-978-562-6040

You should have gotten the installation instructions with the gauge, if you did not let me know and we can email them to you
www.dynotunenitrous.com

cheers
Dan




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