I figured I'd start another thread so as not to turn ccfiero350's swap thread into an alternator thread... Below is a quote from that thread, about how the Ecotec alternator gets turned on. I made a little PWM chip for a kitcar light dimmer project and while it was in the programmer I figured I'd see how easy it would be to make it do 128Hz. 30 seconds later I had a 128.0Hz PWM generator. Thing is, there are 5 more unused inputs / outputs on the chip. As mentioned below, these can be used to do fun things to the duty cycle of the signal, to change the charge voltage depending on certain conditions. The timer is no biggie as well, it can be set to always power up with boosted voltage, then drop down after a set time. Just looking for thoughts as to how to set up the other inputs - is there a set charging voltage that would be good for different things, like AC as mentioned, or anything else? The inputs can either be 12v or Ground to enable the different modes. I'll likely just make 1 version, so if you just want it to output 1 voltage, don't connect any of the inputs. Thoughts? It's pretty simple, once the inputs are nailed down I can make a couple up if there's any guys with Ecotec alternators that want to give it a try. If it works out I could sell them for a couple $ to fund the Fiero addiction. (damn, looking at the preview of this post, you can tell I like the smilies!!)


https://www.fiero.nl/forum/F...2/HTML/082860-2.html

quote Originally posted by ccfiero350: The Pin 1(orange for the L61) If held at 5V will default the generator to 13.8V. It thinks your shorted to B+, it'll run your car and charge your battery but it not going to give you all it's got. There is a lot going on between the BCM (body control module) and ECM (engine control module). The BCM monitors the battery and controls the alternator unless the ECM overides for engine cooling fans are on high speed high fuel demand calc ambient air temp is less then 32 Deg F. There could be a very cool little black box if somebodies good with PWM circuits. Here's the goods to make the generator do its thing all the way. The L-termanal control signal is a 5 Volt pulse with modulated (PWM) signal of 128Hz with a duty cycle of 0-100%. Normal duty cycle is 5-95%. The either extremes are for diagnostics purposes. The following table shows command duty cycle and output voltage of generator. 0%______0V 10%_____11V 20%_____11.56V 30%_____12.12V 40%_____12.68V 50%_____13.25V 60%_____13.81V 70%_____14.37V 80%_____14.94V 90%_____15.5V 100%____13.8V As you can see you could make a Dail-O-Voltage box with this data, if your real good with some programing you can combine timers with inputs so you boost idle voltage when the a/c comes on or just after it cranks for 20 seconds like the factory does. Some stand alone efi controllors have programable PWM outputs just for stuff like this.

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Bob Williams
Working on the next 3800 swap, it works now!!!

Very Nice!

There are a bunch of things you can do to monitor the health of your battery if you have a remote voltage and current sense and temperature readings. It really helps things when your battery is 10 feet away from is charging source.

Performance wise, there is an old trick of turning off the field coils when you at max open throttle. It will free up a few horsepower for the few seconds that you mat the throttle.

If you want max performance all the time monitor your VSS and only go to full charging when your rate of change is low (at cruise) so your not loading the engine by max charging while stop and going.

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yellow 88 GT, not stock
white 88 notchie, 4 banger

quote Originally posted by ccfiero350: Performance wise, there is an old trick of turning off the field coils when you at max open throttle. It will free up a few horsepower for the few seconds that you mat the throttle.

Now that's a good one! Definitely wouldn't happen with a "normal" alternator, but with this one you just have to have a "WOT" input and it would drop to 0%, I assume that would kill the load on the alternator since it's not charging. 4 more inputs to go! Monitoring the VSS may be a bit tough though, extra circuitry needed to buffer the VSS signal, plus processor time to calculate speed from VSS pulses. Possible, but tricky.. I don't personally have one of these alternators (although it's sounding like a better idea all the time!), so these are really about what you guys want. Assuming they're still a good idea? What are people doing now for the alternators in the swaps?

I wonder how much the regulators like being turned off and the alternator spinning fast? Not to well-versed on how rugged they are, but it will free up alot of power as ccfiero says.

If anyone wants it, I coded some C for a 16f84 specifically for controlling the alternator.

Dang, there ya go! Figured it'd already been done before. Good point there though, would be interesting to see how they handle that. Especially if you then drop it back to "normal" charge after letting off the gas. Still spinning pretty fast..

What make of alternator does the Ecotech? I have a 2003 N* in a Fiero, and it has the Nippon Denso 140A alternator on it, the wiring sounds the same, 2 wires went to the ECM or PCM, and 1 to 12V. I will be interested if it is the same style of alternator, and will work.

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84 Fiero Sport Coupe #1192 :: 86 Fiero Base Coupe Quad 4 HO :: 1998 Dodge Neon EX 2Dr 2.0L DOHC Auto