The poor alternator is one of the few weak links in pretty much any Toyota truck made in Japan, both in that they're vulnerable to water/mud, and they have really low amperage output.
As I seem to constantly need the winch because I suck, I wanted to upgrade from the stock 60 amp unit in my 1994 4cyl pickup, and hopefully also eliminate moisture vulnerability in the process (because I live in a moist state). I don’t feel that multiple batteries are a substitute for amperage delivery so a high amp alternator was high on the list for the first changes to this truck.
After a whole lot of reading on the web, I had a lot of conflicting information about what might and might not work. The internet is for porn, not accurate information.
Options to upgrade include:
- A serious replacement unit from Northwest Offroad that can churn out 160 amps, but may still have moisture issues. Would require upgrading various circuits to handle the capacity.
- Rebuild the stock alternator to deliver more amperage... and upgrade various circuits to handle the capacity, and possibly still have moisture issues.
- Use a GM CS130 or CS144 Alternator delivering 105 to 140 amps, which also requires upgrading various circuits to handle the capacity. One way is a single wire installation, or to adapt the Toyota wiring to a contemporary GM 3-wire installation.
- Add a second alternator in place of the AC compressor, and create a completely separate auxiliary electrical system... including a separate battery, which there is little room for.
So after a lot of going back and forth, I decided on the GM option, using an application contemporary to my vehicle.
To physically install the GM alternator, I got a GM to Toyota 4cyl alternator bracket from Trail Gear , part # 120120-1-K (there are several different people making these on Pirate, etc but I wanted to deal with a company I could get support from).
The problem was finding the right Alternator. I embarked on a month long quest for the right GM alternator in the range of 100 to 140 amps with correct case size, and configuration (alternator field, sense, etc). The problem was, I could not nail down a part number or vehicle application for the specific unit I needed, as I was basically trying to fit a part in a hole I had never seen.
Compound this with the fact that there is a serious lack of access to GM alternator specifications that include wiring configuration, "Clock Position" (where the mount and adjustment bolts are positioned), and shaft/pulley set ups. You pretty much have to search random vehicle applications to see the data on each one. An ability to see a list of CS-130 cases with 12 o'clock position in 105-120 amp would have made short work of locating an applicable unit, but I could not find this holy grail of a list. So I spent hours on Napa’s site.
In the long run, what I discovered was Napa Part # 2134530, for a 88-89 Chevy Caprice or Camaro with 305 V8. It has the smaller CS-130 case, which is recommended by TrailGear, but alas there was not a single one available from Napa without a significant wait, and I had only one weekend available to have the truck displace my wife’s new car in the garage.
The closest thing I found available was 105 amp unit for a 1988 Corvette with 350 V8. It has a serpentine pulley which I had to change out, but otherwise pretty much it installed as I expected. It is clocked at 11 o’clock which was ideal for my configurations.
Below are a few pics of the installation process. The wiring is fairly straight forward as you are basically wiring the new alternator in place of the old one, but with upgraded wiring, fuses, etc.
I’m not going to go into the details of 1 vs 3 wire installation. If you want to research this, start here: http://www.madelectrical.com/electricaltech/onewire-threewire.shtml The info these guys have really breaks down the truth from the usual interweb conjecture.
A site that had good info specific to Toyota: http://www.rocketcityrockcrawlers.com/memberstuff/al/85%20Toyota%204Runner%20alternator%20Upgrade%20Project.pdf
This site's info applies the info from MAD Electrical to the Toyota application. Get a wiring diagram for your vehicle to confirm what wiring goes where.
When I get around to doing this modification to my 4Runner, I’m gonna skip all the steps above, and go to Lynnwood Auto Electric, and pay those wizards to build me the exact alternator I want with just the right Clock Position, wiring plug, amperage, case size, etc. It’s so worth the cost to avoid the hassles of locating the right part/application/etc. Pay the pro’s to do what they do every day.
The result so far has been exactly what I wanted- there is no difference in how the truck operates, but the first time I used the winch there was no idle drop at all. Sweet.
The stock Alternator is dowm this rabbit hole. This installation required removing the air box, power steering, radiator, fan, and all radiator hoses.
The GM unit compared with the stock unit.
Pulley swapped from Toyota to the GM, after drilling it out. This process alone would warrant Lynnwood Auto Electric building the whole alternator. What a hassle.
The mount from Trailgear
Mounts Installed, from below
The GM unit installed, with wiring pigtail and 2 gauge battery lead. Insulation from the radiator hose (not pictured) provided by heater hose with wire loom and heat shield tape inside.
In the upper left is the 175 amp fuse, with line coming from the alternator and going to the junction block on the other side of the engine bay.
New Diehard battery, and junction block. Wiring routes from block to front and rear winch mounts, battery, and stock wiring harness.
Yay!
