Foxbody 3G 130 Amp Alternator Upgrade or How to Banish Those Electrical Gremlins From Your Mustang!

Matthew goes through the whole process of upgrading an 88 Mustang to a 3G 130 AMP Alternator to solve low system voltage problems. This video includes a discussion of why you should do this, the parts involved, the tools you will need, and includes the physical install, wiring, and testing of the final installation.
Alternator Kit: Western Motorsports
www.wmsracing....
Alternator - 94/95 Mustang replacement alternator from any parts store
150 Amp Breaker: Amazon Canada www.amazon.ca/...
or any similar part

[@jucedcustoms2274]

Great comprehensive video. We need to do this to our convertible badly!

[@tecmotiondyno]

I cringe when I see these cars show up for dyno with an electric fan and a stock alternator. It isn’t big money, but it is part of the foundation for success with a Foxbody.

[@89Whitehorse]

amazing vid this is way better then lmr. Your my num1 foxbody youtube mechanic. best foxbody channel and your a fellow Canadian.

[@tecmotiondyno]

Not to knock those guys because I think a lot of them are great, but unlike most “KZbin Mechanics”, I am an actual Red Seal Automotive Service Tech, and a degree computer scientist and I am trying to create a spot where you can feel pretty confident in the advice that is given. Thanks for watching!

[@thefoxlife3431]

Another great video. I’ve already done this swap but I like the breaker you used much more than the one I bought. I’ll have to look for this type and upgrade.

[@tecmotiondyno]

I posted a link to an Amazon Canada listing in the description. This part is sold under various brand names on Amazon or through specialty automotive or heavy truck parts suppliers.

[@Scrapla1]

Outstanding video! Straight forward and very helpful.

[@tecmotiondyno]

Glad to help, thanks for watching!

[@garyvanhoosier2472]

Very nice job , this is benifical to me because I am getting ready to do this same upgrade! 👍😎

[@tecmotiondyno]

When you get a stable electrical system in these cars, all kinds of little problems tend to disappear.

[@garyvanhoosier2472]

@@tecmotiondyno agreed the factory missed this issue big time.

[@tecmotiondyno]

I’ve even seen them shut right down with an MSD ignition when the voltage drops below the threshold because you have an electric fan and headlights on, and then crank up the Night Ranger! 😂

[@garyvanhoosier2472]

@@tecmotiondyno good to know since I am doing this before the 6al install too !!👍🤘😎

[@garyvanhoosier2472]

We're is the best spot to mount a 6al box in your opinion.

[@motor_citymuscle288]

Another great video!

[@tecmotiondyno]

Thanks! This really is a good way to deal with electrical gremlins and this is a better way to wire it than any of those “add-on” wiring upgrade kits that expect you to retain the original 10 gauge power wiring and just supplement it.

[@motor_citymuscle288]

@@tecmotiondyno i just upgraded all mechanical parts and now I want to upgrade the grounds and when needed the power cables. I’m also removing safety and emissions crap. So instead of taping them up and leaving them in the engine bay I want to completely remove them. I installed FiTech fuel injection and now I don’t need the stock computer either.

[@tecmotiondyno]

@@motor_citymuscle288 If you have the time, pulling the whole old power harness out cleans things up for sure. Sounds like you have a nice project going.

[@kevinthomas1253]

Clean install!

[@informative_walrus]

My starter selinoid was repositioned closer to the firewall so the battery is a much more convenient location. Any issue with putting it on the positive post vs the selinoid?

[@tecmotiondyno]

That should not be a problem as long as you get a good connection.

[@Backfire10]

Hi. While on the tree at a drag race I want to turn off my alternator so it will not charge during the race. What is a good solution for this that is easy? Can I wire in a switched relay before the stater solenoid? Thank you great content.

[@tecmotiondyno]

I would have to double check which is the field wire, but you could use a relay or switch in that circuit. It is the same circuit you run to your master power switch at the back of the car if you have one. I would advise against this though because the horsepower savings are not going to be enough to make up for the problems you can get with the system voltage drop that will come with this procedure. I do advise that if you have an electric fan that you manually switch it on before staging because if the fan is controlled with a thermostat and it turns on up track, the turn on power draw can be enough to brown out the electrical system and shut off your CD ignition, fuel pump, or even the EFI system.

[@mistersecret88]

I just did this yesterday. No air tools so i used a grinding disc from harbor freight. Took about 3 minutes . I had the parts for 2 years and finally got around to doing it. Shame shame. Lol

[@tecmotiondyno]

Done right, this upgrade normally cleans up a lot of weird electrical gremlins, like when you turn up the Night Ranger a little too much and the car stalls!

[@mistersecret88]

@@tecmotiondyno this happens?

[@tecmotiondyno]

I had a customer who refused to do this upgrade, and yes, when he listened to the stereo at night it would shut off.

[@manueltorres5652]

If we are running out of space on the hot side of the starter solenoid can we connect it directly to the battery? Or what can be done.

[@tecmotiondyno]

You can, or install a separate power distribution lug and connect some of your accessories to that.

[@manueltorres5652]

@@tecmotiondyno thank you!

[@dreydenterezakis7567]

Got the 150 amp breaker off Amazon got my 130 amp alternator I noticed on the performance certification it says 158 amps max load do I need to get a 200 amp breaker or is the 150 good?

[@tecmotiondyno]

@@dreydenterezakis7567 I have never popped a 150 breaker with a 3G alternator. My street rod actually had a 6G 150 amp (at least) alternator in it and I used the 150 amp breaker on it and never popped it either. I think you will be good to go.

[@dreydenterezakis7567]

@@tecmotiondynoOk thanks!

[@toranzoM]

Can I get away with using 4 gauge wiring instead of the 2 that you use? Would that affect the breaker size needed or is 150amp good regardless? I'd rather make my own cables like you instead of buying the sve 4g wire kit.

[@tecmotiondyno]

The shorter the run, the lighter the gauge of wire you can get away with. I would say 4 gauge is the minimum, and I usually use a short run of 4 gauge from the alternator to the breaker because it is more flexible and easier to put in that location. Usually that short run in my installations is under a foot long. For a rear mounted battery box, I usually suggest 0 welding cable. Will a 4 gauge run under the front of the engine to the starter solenoid work? Yes. Will it catch fire? Almost certainly not. Is it my recommendation? No, I recommend 2 gauge. Some aftermarket wiring kits actually ship with 8 gauge, but if you read the instructions for those kits, the supplied 8 gauge wiring is meant to SUPPLEMENT the factory 10 gauge harness, not replace it. 8 gauge is too small on its own for this application, and my personal opinion is that you are way better off doing it the way I show in this video versus using a commercially available wiring upgrade harness with an 8 gauge supplement and a more complicated connection regime. Thanks for watching!

[@crabbypapa3862]

Could you run the output to the starter cable on the late model starters? It goes, basically, to the battery connection.

[@tecmotiondyno]

You could I guess, but I never have. It will increase the overall length of the wiring between the alternator and the main power distribution. When I do a mini starter in one of these cars I usually keep the fender solenoid and jumper the mini starter solenoid to the power cable right on the starter, then when you energize the fender solenoid it transfers power to the power input on the mini starter and triggers the on-board solenoid at the same time. If you have it wired this way, you cannot connect the alternator up to that circuit because it will not have continuity to the rest of the car except when the starter is engaged. If you have a 93 that was factory equipped with the mini starter or you rewired your earlier car to look like the 93 setup, theoretically what you are proposing would work.

[@crabbypapa3862]

@@tecmotiondyno Thanks. I do have a 93. Yes, it Does increase the total distance. I was thinking of not having the extra cable under the front of the engine. Cable from alternator to circuit breaker on frame rail, breaker to starter cable, done. (;

[@gregbrigham3247]

Installed the alternator now my lights gauges and other electronics flicker. Also when i disconnect the battery and turn on the lights the engine dies.

[@tecmotiondyno]

Sounds to me like something is wrong with your installation, or you may have gotten a bad alternator.

[@Mustang8846]

Hi @techmotiondyno. The LMR SVE 3G upgrade kit comes with a 10ft 4 GA power cable with an integrated 200 AMP fuse. So, if I follow your steps for addressing the Factory power cable, this should work just as good right? Although, I may have to run the 4 GA cable across the top behind the radiator, if it is not long enough to run from the bottom.

[@tecmotiondyno]

It’s actually shorter to run it under the car than across the rad, but either works. I prefer a 2 gauge power cable but 4 gauge is usually “good enough”. The 200 amp fuse will be fine too, but a resettable breaker has the advantage of being resettable if you have a problem and correct it. An example would be the main power lead laying on a header primary and shorting. You could fix that problem track side or on the side of the road, reset the breaker and be on your way as long as it didn’t blow up something else important, which is an IF. A fuse has to be replaced and a 200 amp inline fuse isn’t likely something you just have along with you. In short, the setup you propose should work.

[@Mustang8846]

​@@tecmotiondyno - Thank you for answering so quickly. A 2-gauge power cable and resettable fuse will be put in place. I will be installing a new fuel tank with a new fuel pump & housing assembly, sending unit, vent valve and filler neck seal. I'm installing a new fuel filter, and I plan on cleaning and rebuilding the fuel injectors. Once the tank and fuel filter are removed, and the fuel line is disconnected from the fuel rail, I figure I could run some Seafoam through the fuel line, let it set for an hour or so, push more until it is clear, then blow it out completely with compressed air. Is there a better way to do this? I would appreciate your thoughts when you have a moment. Thank you.

[@arnoldheino3991]

can i use 200 amp or should i stick with 150 amp and should i run 4 gauge all the way and is there a special 4 gauge to use or just plain 4 gauge

[@arnoldheino3991]

oh i have a 87 tbird your videos are great

[@tecmotiondyno]

You can run as big of an alternator as you want. The bigger it is, the more attention you have to pay to your wiring, and you will need an appropriately sized breaker or other circuit protection. I usually use 2 gauge with a short 4 gauge run to the breaker from the alternator. Any insulated stranded copper wire is fine. If it is going to be exposed to a harsh environment, such as under the car or somewhere it can be abraded make sure you loom it. Welding cable is a good choice for harsh environments. With a battery relocate to the trunk I usually run 0 Welding Cable from the back to the front. It's heavy, but I never missed a round because the car wouldn't start!

[@dm7097]

Will the factory dash gauge still work of the original two small gauge wires are not hooked up?

[@tecmotiondyno]

Leave them hooked up at the starter solenoid. That way the real charging harness has only one route, through your circuit breaker, but the stuff that is spliced in at the other end will still be powered.

[@dm7097]

@@tecmotiondyno Awesome!! Thank you for the info.

[@staceysims7270]

Part # for alternator ? Part # for Circuit breaker ?

[@tecmotiondyno]

Good questions. I have added links to the specific parts in the video description for you. The alternator is from a 94/95 Mustang 5.0 and can be sourced anywhere. The stator plug may be something you have to get from LMR or WMS. The breaker is available from Amazon or specialty automotive/truck shops, and is often available under a variety of brand names, but the example in the description should give you a starting point.

[@gregthody8723]

@@tecmotiondyno Good video Matthew. Im still running the original alt and have been planing to do this upgrade for awhile. This video answered several questions regarding what size, brand and installation, etc. Very helpful - thanks! Im also enjoying watching the transformation of this little Fox now that’s it’s got a good home 👍