Dataloging software for Megajolt and O2 sensor

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

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BGTSpitfire
Posts: 10
Joined: Fri Jan 05, 2018 9:51 pm

Dataloging software for Megajolt and O2 sensor

Post by BGTSpitfire »

I'm very happy with the MJLJ, but now I'm looking to tune my Weber DCOE's along with the spark to maximum power and fuel efficiency. Before I go and buy an o2 sensor and gauge is there any software that will datalog the spark and AFR side by side?
My low tech alternative would be to have my daughter video the AFR gauge and MJLJ configurator together.

brentp
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Post by brentp »

Hi,

You could connect the AFR gauge to the aux input for the megajolt, and then generate a log file that way.

BGTSpitfire
Posts: 10
Joined: Fri Jan 05, 2018 9:51 pm

Post by BGTSpitfire »

So if the output of an o2 sensor at 14.7AFR is .5 volts. And I set the scaled value on the input channel options as 14.7 as .5 volts it will show up on the data logger? I would fill in the AFR values for the corresponding voltage values to complete the picture. Sorry but I'm old and barely know the difference between hardware, firmware, and software
Thanks

BGTSpitfire
Posts: 10
Joined: Fri Jan 05, 2018 9:51 pm

Post by BGTSpitfire »

Correct me if I'm wrong. A narrow band O2 sensor puts out 0 to 5 volts. If I send that 0 to 5V output to the Aux input of the MJLJ then the Aux input gauge of the controller could be configured to read the AFR. A narrow band o2 sensor would be cheap and easy for me to install in my Spitfire. I'd like to avoid spending money on an AEM 30-4110 gauge if the MegaJolt controller Aux input gauge can do the same thing. The goal is to tune the advance curve and Dual DCOEs for maximum power and efficiency. Data logging them together will give me a sense of direction when it comes to tuning. I'm sure if it is possible someone out there has done it.

BGTSpitfire
Posts: 10
Joined: Fri Jan 05, 2018 9:51 pm

Post by BGTSpitfire »

I'm datalogging with an AEM AFR gauge now but I'm having trouble getting the aux gauge to read in the units that correspond with AFR. It seems that the ADC value of 0 to 255 is what the gauge is displaying. How can I chance the ADC value? Is it as simple as scaled value times voltage equals ADC? The scaled value only accepts whole numbers and they don't seem to be getting me anywhere. I'm really close to having what I'm looking for.

brentp
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Post by brentp »

Unfortunately, the scaling capabilities are limited to a 0-255 range; that's a limitation of the Megajolt system.
Brent Picasso
CEO and Founder, Autosport Labs
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BGTSpitfire
Posts: 10
Joined: Fri Jan 05, 2018 9:51 pm

Post by BGTSpitfire »

I think that I've figured it out. I found this viewtopic.php?t=2072&highlight=wideband
His gauge has a different range than mine so I adjusted the calibration to match mine. You must enter whole numbers so the controller gauge reads 147 instead of 14.7 but that isn't the end of the world. I took a cell phone video of the AEM gauge and the MJ controller gauge next to each other while I tore up the countryside and they had the same values through the range.
Short of going to a dyno, datalogging the AFR and timing together gave me good data as to how to adjust the carbs and timing to get maximum power and economy. If only I could adjust the Webers with a laptop. Maybe I'll adapt bike throttle bodies with MegaSquirt to my Spitfire? The learning continues!!!

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