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Thread: 3g alternator

  1. #1

    Default 3g alternator

    Has anyone upgraded to the 3g alternator for their four eye. I’m having alternator issues. Just wondering what everyone thinks of the upgrade.


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  2. #2
    FEP Super Member erratic50's Avatar
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    Does it make sense to consolidate threads? http://vb.foureyedpride.com/showthre...6-GT-questions


    or maybe start an ultimate 3G conversion thread that addresses the Four Eyed fox and year specific stuff?

    As far as I can tell the 79-85 will be mostly alike because they are all externally regulated. Conversion discussion would depend upon how regulators are handled among other things.

    then the 86's are a four eyed horse of their own. Far more like the 87+ than the early foxes.

    lets start with what year and type of fox you are working on....

  3. #3

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    Quote Originally Posted by erratic50 View Post
    Does it make sense to consolidate threads? http://vb.foureyedpride.com/showthre...6-GT-questions


    or maybe start an ultimate 3G conversion thread that addresses the Four Eyed fox and year specific stuff?

    As far as I can tell the 79-85 will be mostly alike because they are all externally regulated. Conversion discussion would depend upon how regulators are handled among other things.

    then the 86's are a four eyed horse of their own. Far more like the 87+ than the early foxes.

    lets start with what year and type of fox you are working on....
    It’s an 85 car with 92 drivetrain. I think I have it figured out. You can buy a high amp gen 2 but they are more than a g3 and from what I’ve read the g3 will do all you really need.


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    FEP Super Member erratic50's Avatar
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    Watch the amps. The factory wiring is only capable to 65 amps. More than that can start a fire if it's not rewired to bypass the trouble spots

  5. #5

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    Quote Originally Posted by erratic50 View Post
    Watch the amps. The factory wiring is only capable to 65 amps. More than that can start a fire if it's not rewired to bypass the trouble spots
    Got ya. I’m replacing the pigtails and using 4 ga wire going back to starter solenoid.


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  6. #6

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    did the 3G conversion on my 86 just so I can do the contour dual electric fan conversion, was pretty easy and working like a charm so far. I probably would not have done it if i wasn't going to switch to electric fans and I don't have any amps or subs etc.

  7. #7

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    Quote Originally Posted by vrm71 View Post
    did the 3G conversion on my 86 just so I can do the contour dual electric fan conversion, was pretty easy and working like a charm so far. I probably would not have done it if i wasn't going to switch to electric fans and I don't have any amps or subs etc.
    Yea I did mine as well and I am proud of how it is charging. I have an electric fan too and it pulled the 2G down a ton. I got mine from pull apart for 30 bucks and works great. My car has never charged this good.


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    FEP Power Member Broncojunkie's Avatar
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    I went with this conversion kit/regulator on my pace car and just ordered another one for the cobra yesterday. I understand it can be accomplished without this, but it just seemed easier this way. Basically just plug it in and go. I'm not really sure how to do the swap without it and to be honest, I had so much going on with the build that I wanted something I didn't really have to research.

    Attachment 119518

    Attachment 119519

  9. #9

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    Basically when I did my 3g (86 302) I spliced all of one wires, plugged another original wire into the new 3g alt and ran a new beefy cable. If the "warrantied" junkyard alternator would have worked, I would have had all of $60 into it and about 30 mins of work.

    That being said, after it was done, it really didn't seem that different or "better". Kinda felt like a waste of money to be honest.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  10. #10

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    Quote Originally Posted by Haystack View Post
    That being said, after it was done, it really didn't seem that different or "better". Kinda felt like a waste of money to be honest.
    It is if you don't need the current output capability that the 3G offers.

    Matthew

  11. #11
    FEP Super Member erratic50's Avatar
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    Set your idle as per factory spec. Turn on your headlights and your foglights. Turn your defrost on and run your fan on high. Turn on your rear window defrost. Now connect a volt meter at the battery and turn on your 4 way flashers or even just your blinker.

    note the drop in voltage to around 10.7 - 10.8 every time the blinker comes on.

    Now turn on your stereo — even just a factory one — and turn up the bass.

    Notice your voltage at 9.5-10.5.

    If it drops below about 8 the entire system will brown out....

    Also everything demands the same watts of power regardless of voltage input. P= V*A * 1/R so as your voltage drops your amperage skyrockets which adds more heat which increases R. Diminishing returns hits quickly and either something dies or wires melt and your car burns to the ground.

    Now how about that underdrive pulley kit that was all the rage back in the day?

    Now bring stuff like cell phone chargers and inverters into the conversation. Yes you can make it more tolerable by adding a huge 1100-1300CCA battery. It was the “fix” in the 90’s when stereos were the rage and high amp alternators came at an extreme premium. They don’t today.

    I can make the case that it’s not worth the gamble of leaving a stock four eyed fox as-is. Wires are not wine, they don’t get better with age.

    Its your car gang so do as you please, but having personally driven the very same four eyed fox daily and amassing nearly 1/2 million miles on the car over an 18 year daily driver period and another 7 years of weekend warrior abuse these are the things I think are worth mentioning.

    If you go through a car and get rid of the inefficient incandescent bulbs and other simular things this is probably a different conversation.

    But to be clear I will be changing to a optima gel battery and a 3G on both of four eyed foxes. After about the 4th or 5th battery you either explode or cause to melt down by overworking it and the massive water + baking soda cleanup that has to follow - it get OLD. Or there are the cars that have nonexistent framerails and such because nobody bothered to clean up the mess when they replaced the battery, right?

    Just my $0.02 on the topic for what it’s worth.

    Ill buy the beers for a one on one discussion with anyone that wants to make the argument going the other way. And yes - concourse cars are a different animal entirely. I get that. Put that old baby on the trailer and take her around to shows like it was built from the factory.

  12. #12
    FEP Super Member erratic50's Avatar
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    duplicate
    Last edited by erratic50; 03-15-2018 at 09:15 AM.

  13. #13
    FEP Super Member erratic50's Avatar
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    Btw - for those who have done the 3G conversion, what application did you tell the mcparts store counter you wanted an alternator for? I know there are many that work - just curious about what works best.

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    FEP Power Member Ourobos's Avatar
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    94/95 Mustang GT
    1986 CHP SSP Coupe

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    FEP Member brianj's Avatar
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    I got one for a '95 5.0, since i do not have the time to do the junkyard crawl. Huge difference with the headlights and electric fans. The only sound system i have is a Weiand, and the car still would go into discharge at idle at night.
    1983 Mustang G.T. No-option stripper- I like strippers.
    5.0, GT40P heads, Comp Cams XE270HR-12 on 1.6 rockers, TFI spring kit, Weiand 174 blower, Holley 750 mechanical secondarys, Mishimoto radiator, Edelbrock street performer mechanical pump, BBK shortys, T-5 conversion, 8.8 rear, 3.73 gears, carbon fiber clutches, SS Machine lowers, Maximum Motorsport XL subframes, "B" springs.

  17. #17
    FEP Senior Member OX1's Avatar
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    Quote Originally Posted by erratic50 View Post
    Set your idle as per factory spec. Turn on your headlights and your foglights. Turn your defrost on and run your fan on high. Turn on your rear window defrost. Now connect a volt meter at the battery and turn on your 4 way flashers or even just your blinker.

    note the drop in voltage to around 10.7 - 10.8 every time the blinker comes on.
    Just the headlights and rear defrost were enough to notice the dash lights really dim
    at idle, and that was the first night I drove it brand new. That stock alt was barely adequate
    for a no option car (including no rear defrost)
    86 Capri, 5.0, 5Spd, A9L QH/BE, 47 lb Inj PMAS 3" MAF, Single T44 Turbo, Front Mount IC, TW170,
    Stock Cam, Explr Intake/TB, 1.7 Rockers, CF dual friction clutch, 3" DP, 2.5" full Exh, 3.27, 11.932 @ 115.78
    84 LTD, 331-10:1, TW170/Exprl Intake, 47 lbs inj/80 mm LMAF, Full Duals, Quarterhorse, Vortech 7PSI, Lentech AOD, 5 lug Mk VII brakes/rear, Eibach Sway bars, Cobra HB (dads ride, but I fix it )

  18. #18

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    I do have a stock stereo, stock lights and stock fan, plus stock everything else.

    However, I also have about 10 ish chargers, two dash cams, and I routinely hook up my model aiplane charger when I am out flying at the flying field. I did put in a larger battery (it was the same price, so I figured why not) but other then that, nothing special.

    I've found most cars that have charging issue have a badly corroded alt harness (the two 10 guage wires that splice down to one) or a bad ground.

    On my last car, I did the 3g upgrade when I added a Taurus electric fan. With the fan off, I couldn't tell the difference. When it was on, it did, but it really wasn't night and day, it just didn't dim the lights when the fan first kicked on at idle. Driving around, I couldn't tell a difference.

    One thing that I did intend to do that I never got around to, was check the tail light voltage. Stock, the 10 bulbs at the back of the car get down to about 9v's on multiple cars of mine I've tested at idle. I think I has more to do with undersized wires and voltage drop then anything, but I was curious how it might change it. Bumping the idle up to 1000rpm brings the voltage up to about 11.5v's, while the rest of the car sits about 13.5 with stuff off and about 13 with everything on.
    2 1986 cougars (both 4 eyed and 5.0)
    1 1987 cougar

  19. #19

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    I just did the conversion. 4awg from the alternator to main harness (starter solenoid), (3) 4awg grounds directly to the battery. One to the body by the battery, one to engine and one to the body under the passenger seat. @ idle with the car running and no accessories on I get 14.83v when cold. All accessories running I get 14.63v. With everything running hot the voltage normalizes to 14.6v accessories running or not. when the engine is shut off the Battery normalizes to 12.8v. I checked the alternator function to make sure it is not full fielding and it seems to be switching properly. The only add on I have @ this point is a stereo amp that has a max current draw of 60 amps. I have not tested that draw for that yet as the install is not complete. Granted the 3g upgrade is new so I don't feel the testing is complete. For now it seems to test out fine.

    Matthew

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