Alternator Swap

    Quote from MiM

    I think @QuickSilverSS has switched out the alternator... But not sure he did it himself or took to a shop (don't want to assume)...


    @rabtech? You on oem alternator or aftermarket?


    No he didn’t install it. It was done by a HoS in Houston



    Sent from my iPhone using Tapatalk

    Quote from varanog78

    Just ordered a 240amp alternator from JS alternators.
    I will need to do the Big 3 Wiring upgrade. Anyone else on this forum done it? Any suggestions?

    Just ordered everything for the upgrade. Did you find everything you were looking for or still have questions?

    When life knocks you down, calmly get back up, smile, and very politely say, "Is that all you've got?

    Get yourself some 1/0 AWG wire for the "Big 3 Upgrade" connections. Try to get as close to 100% oxygen free copper as you can. No copper clad tin or aluminum. GP Car Audio is a great source for the cabling, heat shrink, and lugs:
    GP CAR AUDIO Ground & Power Ground Pounder


    You can get black cable for the two ground/chassis connections and red cable for the battery to alternator connection or like I did and get a contrast or matching color to the silicone hoses in the Slingshot. You will need about 10' of colored cable for the battery to alternator connection since they are on opposite ends of the Slingshot. I picked up 5' of the black cable for the battery ground to chassis connection and the chassis to engine block connection. Probably won't use that much, but that was the smallest increment I could find.


    Now since most of us don't have the press necessary to crimp battery lugs on 1/0 cable there are other options, but this has worked for me:


    Sorry about the sound track <X


    You'll need 1/0 copper terminals, 1/0 Solder Slugs, 1/0 heat shrink, liquid flux for copper, a vise, and a small torch.


    The battery to alternator connection passes through the engine bay and just before it goes in to the tunnel it is wrapped in split wire loom. I recommend doing the same to your new cable as well. I have the same alternator, including color, coming from JS Alternators. Once it arrives I can do a more official write up. That would include exact lengths of cable so others can have the cables pre-made if needed. Let me know if you need anything else.

    When life knocks you down, calmly get back up, smile, and very politely say, "Is that all you've got?

    I did my own Install on my aftermarket 240 Amp alternator from UA..along with the new + cables & ground ......Pretty straight forward...I used scissor jacks to get under my sling and everything works great now with the new battery I added also....

    Quote from MADDMOE

    I did my own Install on my aftermarket 240 Amp alternator from UA..along with the new + cables & ground ......Pretty straight forward...I used scissor jacks to get under my sling and everything works great now with the new battery I added also....

    welcome aboard @MADDMOE - looking forward to more pictures of your ride and adventures

    Just had my Slingshot ( Bee Bee ) is its name for about 3 months now......and done a lot of Mods this winter to prepare it for the summer season which seems to be coming one day soon I hope.....Been posting everything on the other Slingshot forum but ill hang here for a while to post before the season starts....

    Quote from MADDMOE

    Just had my Slingshot ( Bee Bee ) is its name for about 3 months now......and done a lot of Mods this winter to prepare it for the summer season which seems to be coming one day soon I hope.....Been posting everything on the other Slingshot forum but ill hang here for a while to post before the season starts....

    Been enjoying reading your posts. Hopefully you'll get some riding weather soon!


    Tim "Ghost" Ganey
    Winfield, Alabama
    205spam412spam2868

    Just curious, why are folks swapping out to higher output alternators? The alternator that comes stock is the same one that comes stock with most of the vehicles that have the same or similar motor we have. The big difference is that the Sling doesn't have AC and the cars do, so you should have plenty of power available on the stock alternator unless you have some serious upgrades demanding more juice.


    To be clear, I'm not telling anyone they are wrong, I am genuinely asking the question why folks feel they need a high output alternator and just explaining what my current thought process is. Standing by to be edgumacated! ;)

    lol the stock alternator is 140 amps, once you installed LED lights , upgrade horn, complete sound system especially adding BASS & any other electrical toys....if you see your headlights have the heart beat effect dimming in and out, then its time to give your toy some more juice......so I went up to 240 Amps...they do have a 170 Amp upgrade at U.A. but why upgrade 30 more when you can upgrade 100 more in amps & now my voltage meter hovers around 14.3 not 12.7-13.0...its makes a difference


    You see the before and after pics,,, they don't lie

    @MADDMOE the power draw of LEDs is negligible, even if you had a hundred gazillion... ok maybe not a hundred gazillion... and how often and for how long are you laying on the horn. The audio system is certainly an upgrade that has a hunger for power but unless you are outfitted for audio competitions, it doesn’t seem to me that an upgraded alternator is warranted.

    Ok, but LEDs if installed properly pull almost no amperage at all.


    The biggest killer is the amplifiers of a moderate to large audio system. You could add capacitors, but they are kind of like a band-aid. Say if your system is producing 1500 watts of output that would require in the ball park of 217 amps of current from your electrical system. That's at max which your sound system will rarely ever do, but when it does that is a lot of juice. Most stock alternators are in the 100-140 ampere range and can only supply about half of that for ancillary uses like amplifiers.


    You could do the big 3 upgrade just by itself, however that will in most cases make your problems worse as now the amplifiers have a larger intake capability. So, the alternator should be upgraded as well.

    When life knocks you down, calmly get back up, smile, and very politely say, "Is that all you've got?

    Quote from WraithSS

    Which is always better than facts and science......I'm with ya @MADDMOE. Gotten tired of seeing my headlights dim when that BOOM hits. LOL

    Learning here. The amps in my sling can only push a max of 900 watts at full power. Using your math, would that be about 130 amps? And to be clear, it would only be drawing this power if the amps were configured for full output power and not gained down?
    I know when I push the volume high the volt meter rarely drops below 13 with the sling running.
    Shouldn't I be good in this configuration?

    Quote from Slingrazor

    Learning here. The amps in my sling can only push a max of 900 watts at full power. Using your math, would that be about 130 amps? And to be clear, it would only be drawing this power if the amps were configured for full output power and not gained down?I know when I push the volume high the volt meter rarely drops below 13 with the sling running.
    Shouldn't I be good in this configuration?


    @Slingrazor with a 900 watt amp, your average power use at full volume would be about 43 or 44 amps. Typically, a 130 - 140 amp alternator can handle about a 1200 watt system... I'd say you are good. But as @WraithSS mentioned before, a telltale sign is your headlights, do they dim when your bass hits? If not, ROCK ON!!