08 c6 alternator output switched to fitted and enabled. here's what I found scope

[???]

so looking into alternators for the c6 and it seems to be a weird hybrid only used on c6's, it has 3 wires, L is the turn on lead, seems to be 5v. the F is the alt internal duty cycle sent back to the ecm to tell it the load. S is just the sense wire run to the horn fuse. nothing changes the voltage, the internal regulation targets whatever it was set it. I'd guess 14.2 ish. since that's about the best I remember seeing

well they mostly can't keep up with a stock car in the tx summer heat with ac on, a stock car will drop to 12v. way worse as soon as you mod them or add better fans. there's an aftermarket 600$ alt that puts out more current at idle, but some searching seems to lead to more than a few guys have had issues and boxing them up and paying to send back for rebuild seems like a hassle and something you can't do if you make long distance drives like I do. so that led me to the 2 wire alternators. they need a 5v square wave duty cycle to request the output voltage. I found this off an ls1 tech thread about just using a 10$ ebay freq generator to adjust output on this style. a 160amp alt is 99$ on rock auto, or little more at any parts store when traveling. or maybe even the c7 alternator, since it's wired the same way and some of the zo6 have like 4 fans and tons of electric load which they have no issues handing at idle speed while still handing high rpms.

Commanded Duty Cycle Generator Output Voltage
10% 11 V
20% 11.56 V
30% 12.12 V
40% 12.68 V
50% 13.25 V
60% 13.81 V
70% 14.37 V
80% 14.94 V
90% 15.5 V


I hooked my stock one up to my scope and found the 5v 0hz stock output when running. changed the alt settings in hptuners to fitted and enabled. flashed and got nothing till I went under the turn on stuff in scanner, turned on the L terminal and got 5v and 85%duty cycle. turn it off and it went off.

so I went back and changed some other settings under the alt stuff. just guessing at stuff, since I don't know how the logic works. reflashed, got 5v at 14hz. while low that seems to be a good thing, turned on the L terminal again and it went to 85% again, but this time when I turned it off it stayed at 85%.

so basically before I go randomly punching numbers in, anyone have any ideas of how the logic works. if I could get say 70% duty cycle out of it, might be worth picking one up and seeing how it does.