New 300 AMP Alternator $$$

[Waterloo]

Well, I pulled that puking little Delco 165 Amp alternator off the ProStar with the 600hp CM-871, and installed a Delco 40si 300 amp unit. I ran all new cables, 1/0, both power and ground direct to the battery box. I left the other wiring intact, the ground to the block and the power to the starter. A bit busy under the hood, but split loom and zip ties, it doesn't look too bad.

One thing, I did not know that my interior and dash lights could be so bright! That is the new cable, the old cable was not replaced when I did everything out from the battery box. The truck is actually running better, it felt like a supercharger under the hood. And yes, the new alternator, should call it a generator, is noticeable, as in you can hear it. What I could not get over was how much more responsive the motor is, it actually felt like it suddenly gained 50 more HP. I have to wonder how this will affect my fuel mileage.

As far as fit, it is a pretty big alternator, and it just squeezed in there, it used the outer pad mount bolt holes, and the cables just cleared the fresh air intake to the turbo. The belt lined up nicely, but I think that needs to be replaced with something beefier as Rawze recommended in a previous thread.

The kicker, is the price, $1165 at FleetPride out the door... OUCH! Plus 34 feet of 1/0 cable, shop it, as it can be expensive if bought locally. I purchased 30 feet, I thought that was enough, but I missed it, I needed 4 more feet, which thankfully I had. Instead of using lugs and a bolt, FleetPride had a union for $3... I grabbed a section of 1/0 I had laying around and I had a ground cable. From the alternator to the battery box, at least on my 244" ProStar is 17 feet. Figure 18 and you should be good.

We shall see how this goes, truck is running like a raped ape, waiting for LandStar to call... Going back out there. Three weeks on this new job, and all I have gotten in the bank account is nothing, just covering fuel. My fuel expenses are less than what I figured, but the work is sketchy, and hauling freight for free is not in the cards, especially for GM... I walked away... Waiting on LandStar.

[hhow55]

Mr Waterloo,
Did you ever find yourself a girlfriend?
Time to get away from truck. lol

[Waterloo]

LOL! I'm not suicidal... ;-)

[tree98]

(07-07-2020 )hhow55 Wrote:  Mr Waterloo,
Did you ever find yourself a girlfriend?
Time to get away from truck. lol

Yeah maybe what's her name from your street that you we're complaining about the other day?? Sounds like she could use a good pounding.

[BIASRacing]

Man congrats, we were talking about the system you've got plenty now!

I've been researching, I'm contemplating sending mine off to get reworked, and theres a few more local places I need to check. I just went through the dash and I cured my ground issue! Now at idle with the a/c on and the radio on "not up" I'm at like 14.3 its never been that high.

[Waterloo]

(07-07-2020 )BIASRacing Wrote:  Man congrats, we were talking about the system you've got plenty now!

I've been researching, I'm contemplating sending mine off to get reworked, and theres a few more local places I need to check. I just went through the dash and I cured my ground issue! Now at idle with the a/c on and the radio on "not up" I'm at like 14.3 its never been that high.

IT'S ALIVE! The new alternator helped, but I personally think it was the new 1/0 copper welding cable, ground and power, I ran both from the alternator direct to the batteries. I bought at a local welding supply store...

The original ground to the block was a bit green at the alternator, I sanded her up and installed a fresh lug. The power cable to the starter, I imagine is the same, I hooked her back up too. These are the only two cables I did not replace a few years ago when I replaced everything that hit the battery box. I wanted to swap these two cables out this week, but was under the gun of that eviction from my property due to the neighbor. I will have to tackle those later, when the neighbor leaves for Arizona in the fall... But for now, the truck starts fine, so I am not going to worry too much about it for now.

[smorgan87]

Exactly why mine was replaced with a 170A leece. I never need 320A and i couldnt justify an extra grand for 150 more amps. And yeah. Girlfriends are actually cheaper than trucks if u shop around a bit. If u get lucky u may find one thats less headache too.

[smorgan87]

It is crazy how much trouble an alternator can create by simply not enough output and voltage irregularities. I think thats what was ultimately wrong with my 871. The strange thing. It sat a year and fired up smooth as can be. Same old alternator sitting right at 14v on the gauge now where it used to be about 13v. Runs and idles smoother than my NEW 2350 now.

[Waterloo]

Been through two of them, women, too much grief in this line of work. And trust me, the truck is much more costly on the financial and mental level... And after this terrible year and a half, I have too much baggage to take care of first. It would not be fair to bring that into a relationship.

As far as the alternator, I think many issues could be solved by replacing and upsizing the cabling. I was surprised at the small gauge cable going to the starter, like 3 AWG, the ground was even smaller at around 4 AWG. I replaced with 1/0, which even with the 165 amp alternator I replaced, I believe that would have made one hell of an improvement vs buying a larger amp alternator for most folks. I have that silly stereo, I measured the combined amperage everything would draw if all was on, which is rare, including the truck systems, and came out to 240 amps that the truck would require. I could have gotten away with the 275 amp alternator, but figured the extra amps may come in handy down the road if I do anything else in the cab, thinking about a hot tub... ;-)