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Upgrading to higher amp alternator possible?

N

Nutro

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I read on here or asked and I cannot remember what my options are. This is an 88 that is serpentine on the left side for the Alt, Water pump and crank. Someone recommended I buy this alternator:

https://www.amazon.com/gp/product/B007QBQJHY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

The case is physically a little larger than the original but when I tried to install it yesterday, the bolt hole spacing seems like the bottom bolt hole will not line up with the hole in the head.

I was about to order something like this:

https://www.amazon.com/Billet-Alter...f3624&pd_rd_wg=XoXaX&pd_rd_i=B011A9C20K&psc=1

But is says it's only for V-belt fitment for some reason.

Any other ideas? I'm going to run electric fans etc and want to run around a 140AMP without spending the cash for the power master one.
 
What all are you going to be running? If it's a load that will tax a lower output alternator, ok, need to run one that meets the needs. But if it's just electric fans and a couple other additional small electrical draws, it's likely overkill.

I'm running a CS130 at 105 amps and it's done a good job for me, with my electric fan(s...I only run one as primary). Not suggesting it as the solution, as at least my upper bracket is not stock to a truck. But I am running what I call the semi-serpentine setup too.

If it's possible to get a higher output one that is the stock layout, probably cheaper and less hassle than re-bracketing AND going with one that isn't your vintage.
 
Ah. didn't realize that. I've heard a few people on here made it work.
 
Just checking to make sure you’re upgrading to a heavier gauge charging wire to handle the increased current.
 
Check out tuff stuff. Made in Ohio. They make many configurations based on factory style cases. Mine is 175 amp. Makes a lot of power at idle. I used #1 and #4 super fine welding wire throughout the truck.
332691CB-7803-4D67-8530-87DFA96187B8.png
 
i have pro flo 4 efi system in tank pump,electric windows ,stereo, dual electric fans and run 105 amp with no problem unless you need 140 amp
your asking to find all the bad wires at once........
 
When I had initially installed my 175amp alt I’d only replaced the main charge wires and grounds, didn’t do anything to my original harness. Never fried any wires. A circuit will only flow what amps are demanded by devices on that circuit. In other words, if your 18ga headlamp circuit is drawing 10 amps before the alt upgrade, it won’t draw more after alt upgrade.

You should definitely upgrade the grounds and wire from alt to batt or alt to starter or any new circuits that draw increased amperage. You should also definitely fuse everything except from alt to batt.

In my case, I went from alt to junction block with #1, from JB to batt with #4, from JB to heavy fuse with #4, from heavy fuse to interior sub panel with #4, from heavy fuse to fan relays with #4, from batt to starter with #1, from batt to ground with #1 and various body to frame/block to frame grounds with #4.

28409666-6441-4CED-AA5B-E87ED8F8A934.jpeg 267F48E2-199A-4816-BDF6-EAD56CABDDAE.jpeg

Getting back to my original harness, the few circuits that are left on there that aren’t just relay triggers—aren’t pulling any more amps just due to having potential source with higher potential. Something many of us have probably been through is upgrading the main panel at our house. When you go from 125 amp service to 200 or 400 amp service, you don’t need to upgrade all the branch circuits. You only need to upgrade the main conductors in the service entrance and your ground circuit. A hairdryer won’t begin to demand more than 1800 watts. However, you should definitely be safe and make sure the circuits in your truck, old and new are adequately protected from shorts and overloads.
 
When I put bigger alternators in, I run a new heavy guage wire from the alternator to the battery. The factory wiring stays as is.
 
So right now, the previous owner had a shoddy 4 gauge wire from BAT to starter then like an 8 gauge from POS BATT to back of alternator. Even if I go with stock voltage versus the 140AMP, I want to install new wire. So should I go with 0/1 gauge from BATT to starter then 4 Gauge from BATT to ALT? I've got a 2 gauge ground for the BATT to ALT bracket. I'm also going to run a 4 Gauge from BATT to the frame and frame to motor.
 
I’m running 0ga from battery to alternator and from battery to starter. Also did 0ga for all of my grounds as well.
 
I'm still running the stock GM wiring...alternator to starter (10ga?) copper clad aluminum 4ga battery to starter and battery to alternator bracket.

Two electric fans (unknown draw, but each is on its own 30A relay), heavy duty heater, and fuel injection, off the 105A CS130. I did replace the stock style starter with a mini starter, and those draw far less when cranking, so battery cables aren't as much a concern now.

You aren't hurting anything but your pocketbook going with larger cabling, and with a higher output alternator and larger electrical draws, the alternator output wire should be increased in size. GM got away with the wiring they did because in general the runs are short. 4ga at under 5ft is good to roughly 300A, that is an exceedingly large margin for most anything anyone runs electrically, short of the factory style starter, which is a draw only for a short time.
 
I figured I'd upgrade to new cables anyway and I found a place that sells the 0 gauge for a decent price. I still cannot figure out how to make a new Alt work though. I bought another Alt from Amazon and it was wrong as well. It was a powermaster. I don't even mind running a 105 amp now but not sure what part number I need
 
Take a pic of it in and we can maybe see why it dont work, and what you could do to make it work.
 
Is it possible that you’re ordering for an 88 truck instead of a Blazer. I know some places don’t know that the Blazer and truck parted ways in 88 and I also don’t know if the alternators are different styles either, but something to consider.
 
What alternator was on there? Is it a 12SI like I think it is? Can you measure the bolt hole spacing on it? Maybe that would lead you in the right direction.

I'd expect if there is a difference as to what alternators work for some and what doesn't, its the bolt spacing. The R/V trucks with true serpentine setups maybe all used the CS130s, and why the CS144s work for some but not you? (The roadmaster app suggested is probably a 144)

Way more options than I knew existed, we generally only talk 10/12SI and CA130/144 here https://alternatorparts.com/how-to-identify-your-gm-alternator.html but that can maybe help you at least with what you are starting with. Do you know for certain your brackets are original? Some cars used the semi-serpentine setup as well, and I think they were all over the map as to what used what, what years.
 
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