[HWYSTR455]

I've run about every alt possible trying to find 'the' alt for my application(s), and will gladly share what I've learned:

First, the factory replacement 10si alts are mostly 42a units, and as you know, not enough when adding today's accessories. In my case, at peak load, I draw about 88a, and a good rule of thumb is to double that, so that you're not running at max most of the time. I could go into why I draw that much, but ANYONE who has taken the time to calculate what their' load is with added components KNOWS that a 42a these days just won't cut it on the street. My dual fans alone at kick-off draw 28-32a, just to give you an idea. You add high beams to that mix, brake lights, elec fuel pump, and a stereo, and you've exceeded the max 'capable' load of a factory alt.

Physical Case Sizes- The 10si is in the middle, slightly larger than the CS130. The 12si is larger than the 10si, and in most cases won't fit the brackets. The CS130 will directly replace and fit in 10si brackets, with the only two exceptions being that the clocking is usually not correct, and the belt will need to be about 1/2 -1 inch shorter. The pulley on CS130s, as noted, are usually serpentine, but it's cake to change them. Oh, and the strap bolt (as well as others) are metric on the CS, but no biggie. (See attached pic for a mounted CS130 on my daily driver).

AMP Ratings - Ok, here's the catch, with V-belts, once you go over say 100a, because of the drag the alt puts on the belt, it becomes a balance of belt tension and slip. If the belt slips, the belt is toast, and further slip will prevent the battery from staying charged. Too tight, and you start killing water pump & alt bearings, and in extreme cases, can wear main bearings. IT IS MY OPINION, from past experiences, that you can't SUCCESSFULLY run anything more than say a 140a with V belts. I'll argue this point with anyone, and can give first hand examples. To completely avoid the whole v-belt thing, you can upgrade to a serp setup, which is most likely what I'll be doing in the near future. (But an ex*****ive alternative). Then you can run a higher amp model and avoid the issues with running in high duty-cycle.

Load at RPM- One other thing to keep in mind is the output of an alt at a particular RPM. Just because an alt is rated at 140a, doesn't mean at idle it will put that out. Look for companies that list output at particular RPMs, since they usually pay attention to output ratings. Just to tick you off, I will say that some are not accurate at advertised ratings, just to add to the mess. A good application for an alt that has higher output at idle is like police and ambulances. for example. Watch your volt meter while driving, and usually anything below 13.2 for any extended period is a good indication you're not where you're supposed to be.


Harness Adapters- No problem, and not only do people like PowerMaster offer them (see attached pic), you can grab one from the Help! products section at local auto parts. I've heard there's a trick to making the idiot light work, but I've never had that issue. Will say though if the belt is slipping, the light won't light up, so best thing to do is have a volt meter!

Other Things to Know- Number cause of failure on CS130s is heat. There are some that come with fans that help cool better, but in the long run, life on these alts is limited. Best advice- always have a spare on hand! In the trunk if going on trips, as well as a spare belt or two. On average, I get about 1 year or 20k max miles out of a CS130, as an example. I just did 3 200+ mile round trips to Philly from DC, and cooked one in between. I dropped back to a 10si spare because my spare CS130 hasn't been repaired. You can do that, but over time, the battery will be discharged and will cook the 10si. NEVER use an alt to charge a battery, will argue that one too if any would disagree. After driving on a lower-than-required alt load rating, put the charger on the battery.

CS130 Sources- A couple auto parts now carry PowerMaster alts, which is nice. I've been having fairly good luck with East Coast, and there are others that are acceptable as well. You could buy a new one and change the pulley, but in x period of time, you'll be replacing it anyway, so why bother IMO.

I think that's all, but if something comes to mind I'll add. Anyway, hope that helps some!

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