Really? Lol. OK. Well good luck with your setup... let us know how it does mid summer with the AC on while idling....

 

Forum gets a little savage sometimes....

I ended up buying a dorman replacement. I couldn't see an old fan built in the 90's being a better replacement than a new one, even if it's made out of Chineseium.

 

I’m sure it will be fine as long as the blade design is an exact copy of the lincoln MKVIII fan. Make sure to use foam/rubber weather stripping to seal the shroud to the radiator. 8-10ga wiring and 50 amp HD relays... it should work well.

 

I will and I'll be truthful about it. As an engine is producing its least amount of power when idling it's also producing its least amount of heat. My only issue at this moment is the very low output of my 10-SI alternator but the new 12-SI should fix that. You are aware the very heavy rotor inside a CS-144 is a real belt eater, aren't you? I suggest buying a 94 amp 12-SI like I did so you can use a stock mount bracket and cut a lot of the needless power loss from spinning such a heavy rotor.

 

sigh. So much bad information being posted.

12SI alternators are not brushless.

12SI Delco Remy alternators are not 1-wire. You can find aftermarket ones or rebuilt ones that are, but you want 3-wire so the light works and you get the advantage of the remote voltage sensing.

50A at 1000 engine rpm is NOT astonishing. It's a joke actually.

The CS144 can easily produce about 80-100A at engine idle, say 700rpm, depending on the crank to alternator pulley ratio in use. The 140A CS144 is the minimum alternator to consider when adding electric fans. If not it, then the newer AD244 design.

Of course, you need to use a reasonable crank to alternator pulley ratio. You'd want the CS144 turning at least 1800rpm at idle so you could expect >80A out of it. This means the pulley ratio should be at least 2.5:1. A typical crank pulley is around 6.75" give or take a bit so you want the alternator pulley to be in the 2.625" range to achieve this.

Of course, even with a crappy 2:1 pulley ratio, the CS144 might produce 60A at 700 engine rpm and still put the 12SI to shame...

I would NOT recommend a 12SI if adding electric fans. Jump right to a CS144. It will fit just fine.

 

I bought my 12-SI only because it was a modern version of the 10-SI and with the same overall case dimensions. Then I stumbled onto this Delco Remy performance website and discovered the 12-SI had one of the very highest amp outputs at very low speeds. I was needing a lot more output down low and the 12-SI will deliver it. An output of 50 amps at only 1000 engine rpm is a LOT of output and from a package the same size as a 10-SI. http://www.dieselusa.com/productinfo...on%20Guide.pdf

 

Wow.. You must be an “engineer”....

I don’t normally do this on this forum because I’m all about helping people here 100% of the time..my results are based on testing and experience, I always report the good and the bad. Let me break it down for you since you’re giving me advice.

My car has been together for 8 years/23k Miles, has made over hundred 10 second passes, tons of street racing, highway rolls etc... I have driven it cross country twice in 3 years, it gets driven in bumper to bumper Houston traffic in the middle of Summer with AC blasting and I literally can use it as a daily driver if I want. I put it together, I designed/installed the systems in place to make it reliable. I have a pretty good idea of what works. So thanks for the advice, but I don’t need it.

As for your 12si, it’s not going to make **** at idle, just like your stock 10si doesn’t. A stock LS5 idles at 600-700 rpms in drive, your alternator will do NOTHING there with stock pulley combos. Fans, lights, AC and stereo will have you idling at 11.8v until you eventually overheat or the battery goes dead. If you don’t get an alternator that will make atleast 100 amps at HOT idle, you are wasting your time changing it. You’ll still be sitting there with dim lights, weak fan, climbing temps and luke warm AC.

Thanks for the concern about my CS144 robbing too much power from me. Lol!

 

I ended up with this one. https://www.summitracing.com/parts/pwm-8207

Fits SI mounting points exactly. Just swap sheaves, get an adapter field harness, and you can swap back.

Of course you have to update the charging conductor.

 

This is the fan blade design you want for max flow...



This is a PROVEN product. Hopefully this is what your Dorman fan will look like.

 

Did you upgrade your "home" set-up too???

https://www.corvetteforum.com/forums...n-15-amps.html

 

How many amps do they draw and do you know the cfm rating?

 

Say what? That bold statement is completely wrong. There are lots of alternators that produce more output. The CS130 and CS144 were designed and put into service on GM vehicles because the 10SI and 12SI have CRAP idle current output capabilities and were not keeping up as new electrical loads were added to cars.

An "upgrade" that still doesn't work under all driving conditions is a useless badly executed upgrade. The 12SI will be under 30A output at a SANE 700 rpm which is USELESS with electric fans. Not much of a fix when it doesn't fix the idle output problem and still lets the battery go dead.

 

According to the Delco Remy specifications you are dead wrong in your assertion that the 12-SI is crap. The 10-SI produces very little output at engine idle speeds but the 12-SI cranks out a VERY impressive 50 amps at an engine speed of only 1000 rpm. So rather than making baseless assertions based on ZERO knowledge of the subject I suggest you read the specs: https://www.ebay.com/itm/New-Alterna...ZW3RP3&vxp=mtr

 

And by the way, the heavy duty CS-130 and CS-144 alternators are worthless for high performance applications because they have extremely heavy rotors that will eat v-belts alive at high rpm because of belt slippage. With their heavy rotors and heavy duty construction they are intended for light trucks with serpentine belts and medium speed engine rpm operation. Look closely at the Delco Remy specifications and you'll quickly see the so-called "heavy duty" alternators usually have very low outputs at low shaft speeds; lower than the "crap" 94 amp 12-SI with its much lighter rotor that is very well suited for high rpm use. http://www.dieselusa.com/productinfo...on%20Guide.pdf

 

I have read these 12-SI alternators are brushless and self exciting at least a dozen times but when I look at the side view in the Delco Remy performance specifications it shows them having brushes just like the 10-SI. So now I'm trying to figure out where I had read they are brushless and self exciting. Am I losing my marbles? It's sitting in a UPS terminal in El Cerritos California so it should get moving early this morning. As El Cerritos is just 250 miles south east of me I would think it'll arrive on Tuesday morning. With a 3" pulley it should solve my low output problem at idle in DRIVE or at least help the problem because according to the performance specifications the 94 amp version will crank out about 33 amps at an engine speed of 650 rpm in DRIVE and about 45 amps in NEUTRAL at about 800 rpm.

 

Long gone. You have no clue what you are talking yet insist on posting bad advice.

I already told you the 10SI would not work in another thread even though you insisted for post after post after post that it was being upgraded and would be fine. Now, suddenly you're the expert on how the 10SI is no good and how the 12SI that you have never ever used is the perfect solution.

 

I’ve never tested the amp draw or the cfm, but it’s reported the lincoln MKVIII fan requires 50 amps at start up and around 30 amps continuous consumption on high speed.

You are posting so much bad information, it’s not even funny....”Are you making this up?”

First off, a 12SI is not brushless, never has been brushless, never will be brushless. It was a 1980 design weak *** attempt by Delco to upgrade the 10si. I serious doubt it makes a true 50 amps HOT at 1000 rpms, but even if it does, so what? You don’t idle at 1000 rpms. The difference in 700 idle speed and 1000 idle speed is huge. That alternator will do NOTHING at 700 rpms...

One key fact you are forgetting which is huge is that HOT temp voltage is what you need to be concerned about. Alternator output drops big time when they get hot, along with increased resistance on the rest of the system. A 10-12si is not vented well, has a cheesy fan and will certainly drop voltage when it gets hot.

Where as a CS144 is vented well, has a huge fan, large bearings and designed to carry heavy loads and high temps. It was used on 90’s caddies, corvettes and Impala SS. As for eating belts and high rpms, your comments are asinine. I have been on the same belts for 8 years, my car goes 6300+ rpms every time I drive it and I have never ate or thrown a belt. Your comments are just dumb.

You need to listen to members that have done this stuff, not reading advertised junk from a 1983 Delco Remy catalog.

Open your mind and listen.

 

I'm guessing his setup will be capable of around 20A at 700rpm idle. There is nothing outstanding about that kind of weak idle performance.

 

I'm not standing up for toobroke here, but has any one of you tried using an upgraded 100 amp or 110 amp 10si or 12si to run 30 amps of fan(s)?
Or did you automatically upgrade to something bigger and assume that the 10si or 12si would not work?

 

The simplest answer is that is exactly what GM did. As cars started using more power, GM designed alternators with higher output.
The SI series reached their design limitations.
If you want modern amenities, you need to do what they did.
Use a more modern unit.