Slippery UltraDork
1/15/20 10:19 p.m.

Anyone have any idea and maybe point me to where would I be able to find a higher-than-factory output alternator for a Toyota 3F?

The engine was originally found in the FJ62 series Land Cruisers, its the updated one with the fuel injected engine. I would say 1988 or so. 

I used to know of a place that would redo the windings but they are long gone. 

I'd like to find one with around 120 amp output. I believe the current one is an 80 amp alternator and it cant keep up under full load. 

I don't have any good pictures at the moment, these are all I have. I can try and get more, will not see the car for a couple of months. 

Slippery UltraDork
1/15/20 10:21 p.m.

Also, a couple more things:

  • I am OK with sending mine in or buying one and having it reworked if you guys know of a place that I can ship it to. 
  • Is it OK to have a few circuits running straight off of the alternator like the picture below? I never seen anything like that. 

Dr. Hess
Dr. Hess MegaDork
1/16/20 7:04 a.m.

As for the wires running off the back of it, that's kinda unconventional, but from a straight electrical perspective, it doesn't really matter that much.  It is more or less like hooking it up directly to the battery.  The wires should go to a fuse for safety purposes.


For higher output, try to find something that Toyota used that looks about the same.  I recently bought this:



on Rock Auto for my LX470.  It's 100 amps versus the stock 80.  You could also add an extra alternator or generator if you have the room.

What are you doing that causes you to tax out a 1KW alternator? 

Curtis73 UltimaDork
1/16/20 1:09 p.m.

Do some googles.  This isn't about simply upping the amperage of your alternator.  Just like with wiring, an alternator is capable of carrying X amps regardless of how it's wound for your application.  Sure you can rewind it for 300, but don't expect it to last under high-draw periods for more than a couple minutes.

Audio folks go nuts with old-school GM alternators and squeeze 80-90 amps out of them, and they do OK because the heavy audio draw is only very short and periodic.  I tried that once... I put an 80 amp 12si GM alternator in an old wagon and the first time I jump started it the alternator fried.  Once it started, it was supplying all the battery could swallow and got so hot it gave me 2nd degree burns.  But 80 amps in a CSI case is a cake walk.

Think of it like a circuit for an amplifier.  You have a 250w amp so you need 21A.  Great.  You install it with 8ga wire and a 25A fuse.  You have a little bit of headroom with the 8ga wire.  So if you want to go with 400w amplifier, just install it a swap to a 30A fuse.  But that's your limit.  Randomly rewinding an alternator for more output could  be like putting a 2000w amplifier on that same circuit and a 160A fuse in front of it.  That 8 ga wire will fry in no time.  The googles might tell you how much "gauge" your alternator can support.  Does any of that make sense?

I'm just suggesting to do some research.  You're likely fine to 100A, but its hard to tell.

Try (believe it or not) summit racing or Jegs.  Rock Auto is a good one to check.  Amazon has a pretty good selection as well.

Slippery UltraDork
1/16/20 2:48 p.m.

In reply to Dr. Hess :

If I had the car here it would be very easy for me to just measure and machine a bracket to adapt a different alternator. And its dofficult for me to do this remotely or take measurements where its at. 

I had problems mainly at night in cold temperatures. Heated seats + lights running. I know 1k watts is a lot, but I was surprised when I started adding things. I know not everything runs at the same time, and that how I was able to make it back but its not optimal. 

Lights 210 watts
Seat heaters 240 watts (think Vt/Canada in an FJ40 with canvas top)
ECU + mis 100 watts
Fuel pump 120 watts
Radio + cluster 120 watts

That ads up to around 790 watts. We were running the heater that adds another 300 watts!, so right over 1000 watts. 

I just rechecked my notes and I think the alternator is a 65 amp unit, not 80 as mentioned before. 

There is a winch there that was needed that day, along with a small air compressor for the ARB lockers. The later is not a huge deal, but the winch draws quite a bit. 

I now know how to deal with it and nurse it, but I'd love to have more headroom. 

Slippery UltraDork
1/16/20 2:49 p.m.

In reply to Curtis73 :

I'll go over your reply in a bit. There is a lot of good info there and can't go over it now. 

Mr_Asa Reader
1/16/20 3:04 p.m.

There are a couple places that rewind alternators here in Tampa. Want me to dig through my notes and get you some numbers?

Dr. Hess
Dr. Hess MegaDork
1/16/20 3:12 p.m.

Fuel pump is probably half that.  I measure around 5 or 6 amps on the ones I've tried.  3 amps on the one on the Sportster.  You wanna talk tight electrons, try running a fuel injection system and a motorcycle on 18 amps.

Those seat heaters are your killer.  System just wasn't designed for that.  So, yeah, get the vehicle and upgrade it to a properly sized alternator like the one I put in the LX470. 

californiamilleghia Dork
1/16/20 3:58 p.m.

Does it need to be a Toyota alternator ?

just wondering what  Ford Police cars are using ?

Mr_Asa Reader
1/16/20 4:19 p.m.

In reply to californiamilleghia :

By now, probably a 6G alternator.


I did an upgrade for my '93 F150 from an 80A 2G to a 130A 3G several years back.  Its been a great upgrade.

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