I replaced the stock alternator on my 2017 Tacoma SR5 that has the tow package.
I replaced the stock alt with a custom built 320 amp alternator from
(excessive amperage) (
High Output Alternators | Excessive Amperage (https://www.excessiveamperage.com/))
(I contacted them on Instagram because they have a lot of pictures & videos posts about their alternators, I ended up getting in contact with Nathan the owner of excessive Amperage the guy was super helpful and answered all my questions)
I paid ($525) with free shipping and also a free paint coat (Red).
The alternator took 2 weeks to come in and bolted on exactly the same as the stock alternator as well as used the same wire harness plug and ran at the stock voltage, (Which later I changed). The alternator has a smaller pulley so I had to replace the serpentine belt for one the was a half inch smaller. Everything was pretty easy besides removing/ installing the back bold of the alternator. Initially I had concerns that the new alt would cause a check engine light but thankfully it did not, everything went well.
After about 2 weeks of using the alternator everything was good but i realized that i wanted to run at a higher voltage then the factory 12V. I ended up contacting Nathan and asked him about higher voltage options and he told me that if I sent the alternator back in he could install an internal voltage regulator that would bypass the stock voltage of 12V and allow 14V though I would no longer use the factory plug harness and would have to find A 12V ignition source.
He said he would do this upgrade free of charge if I paid for the shipping fees there & back. I agreed after asking many questions haha, I had many questions about if it affect the computer and or battery / other electrical components and if it would cause a check engine light. He said everything would be fine except there was a chance that the check engine light would turn on but that everything else would run fine as long as voltage stayed under 15.2V. I decided to take my chances & go through with it.
About a week and a couple days later I received the alternator with the new upgrade. I ended up getting a 12V ignition source from within the fuse box next to the battery. I got everything installed and surprisingly everything worked great and there was still no check engine light on!..
The alternator gives out 14.4V at high RPM and 13.8V at idle. I get about 220 amps at idle and up to 340 amps with a heavy electrical load. This was all done in September of 2020 the alternator is still running great haven’t had any problems with anything electrical nor things like headlights getting to hot(have read about stuff like that) I don’t hear any squeaking from the alternator and I am still using the same battery I was using before the alt upgrade, which is a Optima DH6. The only thing I would say I do notice is that the headlights get slightly brighter when I accelerate and drop back down to normal brightness at idle but so far I don’t have any problems with anything.
Prior to these upgrades I did do a (big 3 upgrade) which is an electrical wire upgrade for the engine/alternator/battery. I did not replace any wires I only added 0 gauge wire for the grounds and positive.
The serpentine belt I used to accommodate the new smaller pulley is
K070830 Premium OE Micro-V Belt.