rough estimate says that's pretty close to maxed out.

 

Just bought a LS1 alternator off of some guys on the e-baay....they sell it rebuilt and bumped up to 160 amp...only a 115 bucks too. so far so good on my car!

 

You can get all sorts of ratings here

https://alternatorparts.com/ad230-ad...ternators.html

Presumably you're in a hot climate, hence all the fans ? So they may be on a lot ? If so, it would make sense to go big.

 

Not quite the same but I'm using a 145 amp truck alt with the following loads:
Dual Derale Coolant Fans
Single 12" oil cooler fan (brand unknown)
Twin 255 pumps
Electric cutout
Stereo and amplifier
So far so good for one year and counting...

 

Thanks Guys. I'm going to bump it up from the stock 145 amps truck alternator.
It would be a bonehead move to go through the aggravation & money only to find out that 145 amps is just getting by.

I'm searching for an in stock, ship tomorrow solution.

 

Mechman 250A would get my vote...

 

Just thinking out loud about your issue,,
If your running that many fans,, do the pusher and pullers drive through the same part of the radiator?
Because I worked at a place where we tested it and your LOSING air flow per amp if your stacking them..
If the fans don't pull the same CFM one becomes a parasite of the other..

It might be cheaper in the real long term, to upgrade your radiator to a higher efficiency one and
drop back to 1 really good set of draw through fans. Run a wetting agent will buy you a few percent.
Blade style Fans pushing are less efficient than a draw through setup "most" of the time, they make up for it
in making their motors more powerful.

YMMV and good luck...

 

 

 

 

 

Good to hear that the pusher fans located on the front of the condenser are working for you in Fl.

They worked for me here in HOT KS, but only up to about 100 degrees ambient. After that not so good.

Note that when you are NOT running your AC that there is little need to run the AC condenser fans. The puller fans on the radiator should easily be able to keep the engine cool if they are high capacity fans like Spal or other brands. So in cooler weather, I just turn my ac condenser fans off.

What I found when I tried to install the truck 145 amp alternator is that the alt is a little larger in circumference. So its center moves to the driver side of the car within the fbody alt bracket about 3/8 to 1/2 inch. As a result the pulley on the alternator touches the bolt head on the ProCharger pulley. The fbody alt bracket stays in the location and the j bracket stays in the same location which is not the issue. As you probably already know, you have to modify the thickness of the blower pulley washer, and use a round bolt head rather than a hex head bolt to clamp down the blower pulley in order to get enough clearance between the two (alt pulley and blower pulley bolt head).

Don't know if the 250 amp alt circumference is larger than the 145 amp truck alt or if it fits the stock fbody alt bracket. So when finding examples of fbody owners using it successfully, make sure to check if they have a ProCharger attached to the alt bracket. Else you might find yourself with a alt that you can't get to fit because of clearance issues.

 

pretty much all new high amp alternators are based on the large truck case AD244 but I have seen a couple AD230's rated at 160A

I have had to grind the crap out of the case and the block to make AD244's fit in low mount apps, but they do fit.

another thing to consider is that the AD244 taps out at around 18,000 rotor rpm. either the regulator overloads or the brushes float.
Thats like 5500 rpm with stock truck accessories.

So if you see voltage drop at the top of your shifts, move to a smaller crank pulley or a 3" alternator pulley.

 

From my research most alts tap out at about 6250 but regardless if this one taps out at 5500 that's even worse for those running larger than stock fuel pumps or dual pumps. The lower voltage can make it appear the injectors are at 100 percent duty cycle when it fact the real problem is the alt tapping out if revving to 65-6700 rpm. The pumps won't be getting the required amps at that those rpms - 14amps at the pump for a single (340) and more for duals.

Since the 4l60e is not rated to spin over 6200 my tuner set my shift points at 6250 to be safe.

 

Interesting stuff, I just have the 115 amp alt, using one wire (signal?)
I run a Holley HP, 2 fans, 2 fuel pumps, plus all the lights, etc-the fans are staged, but both
do come on at an idle, and the pumps are staged, sec. comes on in boost. I haven't had any problems,
but I should look into a bigger one, if this one is struggling, if could burn it out quicker. Right now its
tight getting the power steering pump lid off, anything bigger it would be impossible, unless my case
could be updated.

 

If it helps.. The non reservoir power steering pumps off a Jeep are the same Saginaw guts as the ones chevy uses,,
they are only about 4" in diameter and use a 1 quart tank on the fender of fluid.

 

 

i get mine from the wrecking yard. most denso alts have a 17mm shaft and use a 6 rib pulley with an 8mm offset

that said, march makes a 3" one for super cheap. #120-08

 

This is info that I found. In general you don't want more than 16,000 rpm at the alternator. Race alternators can take more, but most stock alternators start to shut down beyond that. The set point at minimum and at maximum rpm is specific to every alternator and you have to check manufacturer specs to find out that info.

Unfortunately stock alternators are designed with the factory stock setup in mind. LS1 Fbody alternators are a good example. Start to rev past 6500/6600 on the stock setup and the alternator drops off and doesn't charge. So you go from 13.5v to 12v or less instantly depending on your battery.

To calculate total alternator rpm - Crank pulley size / Alternator pulley size, then multiply by engine RPM.

For example: typical Procharger scenarios.

ATI Damper with a 7.65" Diameter
Alternator pulley is 3.5"
Spin engine to 7400

This setup calculates to a total of 16,174 alternator RPM - borderline.

ATI Damper with a 8.65" Diameter
Alternator pulley is 3.5"
Spin engine to 7400

This setup calculates to a total of 18,288 alternator RPM - over maximum threshold.

LS stock truck alternator (2.375 pulley)

ATI Damper with a 7.65" Diameter
Alternator pulley is 2.375"
Spin engine to 7400

This setup calculates to a total of 23,886 alternator RPM - over maximum threshold.

************************************************** **************
The best solution is to change the alternator to an aftermarket race specific alternator that puts out more voltage where you don't have the rpm issues and you can adjust the charging curve.

But you still might require a larger than stock pulley on the alternator. The downside to installing a larger alternator pulley is that they don't charge as well at idle. There is an rpm level where the alternator starts to charge and an rpm level where they drop off.

ATI Damper with a 7.65" Diameter
Alternator pulley is 3.5"
Engine at idle at 900 rpm

This setup calculates to a total of 1967 alternator RPM.

High end alternators let you adjust the curve. It depends on what your requirements are. PowerMaster has some good information explaining how their race alternators work. Pretty good stuff.

Here's a real world example:

"Been there and seen that in the data. Real scary when voltage drops to 11v or less at WOT, (6k+ rpm) and fuel pump slows down, pressure starts to drop, AFR gets lean, lucky I was in closed loop and injectors went to 100%