For pyro, the Navistar official recommendation is to keep it below 1250°F sustained (pre-turbo measurement). Many people run theirs higher for short bursts, but you don't want to see a sustained value over that.
My OBS truck has a factory voltmeter, but it is practically worthless. I had an alternator go bad and start overcharging (well over 16 volts). The warning light came on, but the factory voltmeter still showed a "normal" range. Fortunately I had a voltmeter sitting in my console (I have ISSPRO Performax gauges, which allows plug & play swapping of gauges). I plugged the voltmeter in, and immediately thought my engineers had screwed up since I couldn't possibly be getting 16.8 volts. I pulled over and dug the Fluke out of the toolbox and confirmed that the gauge was reading correctly.
The funniest part was the NAPA guy trying to tell me that 16.8 volts was perfectly acceptable out of an alternator, and that Exide agrees with him. I was able to tell him that in my previous role overseeing electrical and electronic components for a major forklift manufacturer, I had the official statement from Exide limiting continuous charging voltage to something like 14.1 volts.
Regards,
Michael Pliska
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