High Output Alternator opinions

[Jengel451]

Hey all, I've been running a Tuff Stuff 130amp alternator, but now that I have added Dual Fans I found its Achilles heal. Low RPM/Idle Charging (or lack thereof). Looking to switch to a GM 10 or 12SI unit.

The question: Who has the best Idle output that you've seen?

NOTE: I have already done all the re-wiring, 1ga feed direct to battery, 8ga Alt Ground. Relay 12v signal wire direct from Battery to regulator, bypass Amp Meter etc etc etc. I really don't need to be versed in what old Mopar did and why, just want honest opinions about GM 10/12SI manufacturers.

AC Car, Convertible Car
Aftermarket Stereo and Amp
Contour Dual fans (this is the one that pushed things over the edge)
Sniper Injection
Hyperspark Box
FI fuel pump
Group 27 AGM Battery (New)

In general, rough math is looking like I'd need somewhere around 95amps at 800 RPM Idle. Mopar Tuff Stuff Alternator is spinning at ~2200 rpm. When sitting in traffic at idle with everything going, it's dropping below 12v until about 1500 engine RPM's then it comes up. Regulator is good, swapped in 3 new ones and all had identical behavior so I know the Alternator isn't up to task at Low RPM.

EDIT: Looking at this Alternator. Seems to have the exact same mounting as the 10/12SI. 145amps output at Idle.
Powermaster 857296-1 Powermaster HPR Small Frame Series Alternators | Summit Racing

 

[live4theking]

Did you ever consider changing to a smaller pulley on the alternator you already have?

 

[Jengel451]

Did you ever consider changing to a smaller pulley on the alternator you already have?

I actually did. After a short chat with Power Master/ TuffStuff and a couple others I found out that in order to get the Mopar armature to spin fast enough I'd have to go down to a really really small pulley and that would make the High RPM range eat the alternator. That and since I'm running the CVF 8 rib. Nobody makes a smaller pulley.

I went down the rabbit hole on Mopar "Wye" windings compared to "Delta" windings of others and why Mopar cases have limitations.....broke me head a bit. Stock OEM setup, it's fine but once you try to make them do modern stuff, we have issues. Another reason why the Modern cars all have very similar looking Alternators, everyone learned.

 

[CBODY67]

Are there other brands/types of cooling fans that take less power to run?

 

[Jengel451]

Are there other brands/types of cooling fans that take less power to run?

yes, but amperage equals cooling power. Never ever go by advertised CFM as those numbers are a lot like LED Lumen numbers, all over the board and never equal true LUX numbers.

 

[Trace 300 Hurst]

Interesting discussion about 'lectrickery by someone who actually seems to know what he's talking about.

Watching.

 

[Jengel451]

Interesting discussion about 'lectrickery by someone who actually seems to know what he's talking about.

Watching.

I don't know if I'd go that far..... I know enough to be really really dangerous.

 

[Trace 300 Hurst]

I don't know if I'd go that far..... I know enough to be really really dangerous.

Dangerous or not, you knew enough to write "I really don't need to be versed in what old Mopar did and why, just want honest opinions about GM 10/12SI manufacturers." That silenced a lot of keyboards that wanted to chatter about fatter & direct wiring, bypass mod, fusibles, amp gauge, bulkhead connectors, grounding, "single and dual" field alts , LI batteries, etc, etc, etc, etc.

Interesting point about modern cars all having similar alternator architecture. I think I subliminally noted that 20+ years ago but never put a millisecond of actual thought into it. And I'm not going to start now!

 

[CBODY67]

yes, but amperage equals cooling power. Never ever go by advertised CFM as those numbers are a lot like LED Lumen numbers, all over the board and never equal true LUX numbers.

What problem is "massive cooling power", compared ot a normal 17" fan (and shroud) with HD clutch, seeking to overcome?

Just curious,
CBODY67

 

[Jengel451]

I'd love to use the stock 7 blade and shroud, but with a slightly deeper rad and real-estate taken up by Serpentine belts (V Belts slipping at 7K RPM sucks) I'm left with 3.5" of clearance and the short clutch and fan spacing back to the AC compressor leaves only room for a 2" deep fan blade (Only Hayden Makes one for a clutch), If I can get it to fit without the clutch hitting the rad I'm left with negative spacing. Solid mounting also has the V Belt slip issue, only magnified.

I thought about moving the engine and trans back a bit, but the TrickFlow heads actually touch the firewall on the passenger side as it is so that makes it a non player. The other option is to modify the core support and push the rad, AC Condenser and Trans cooler forward without messing with Grill and hood latch location.......

Electric fans it is.

 

[CBODY67]

HOW often is 7000rpm used?

 

[Jengel451]

HOW often is 7000rpm used?

Whenever I want to. How about you let me do me and you do you.

 

[CBODY67]

Curiousity drove my question, no more, no less. If a better understanding of the total issue is had, better answers can result.

Enjoy!
CBODY67

 

[Welder guy]

I’m using a 1996 dodge Dakota 120 Amp alternator. It works like a charm. No more pulsing lights at idle.

 

[James Romano]

So if you're "doing you" then what kind of opinions are you looking for on this? I've read that yes, you can install the GM alternator with some bracket mods/aftermarkets stuff. Sounds like you're not the slight bit interested in original equipment or restoration... so by all means, go for it.

I think the old debates came down to internal VR's vs external.. which is the old "single wire" conversation that always comes up on this one. At one time, I was going to switch mine to a larger Alt, but I found I had enough power out of mine for what I needed. But I cruise, bar hop and go to shows... no racing anymore.

For you... I don't really see what year car... or motor you're running listed in your post, but if it's a convertible from the mid 60's... 318 (poly)? Late 60's 318/360? or maybe you swapped it for a big block...maybe it has one already. Need to know because the wiring looms are different length and possibly in different routings.

Here's some interesting reading for you from the A-bodies forum back in 2009...
Anyone using a GM 10si or 12si alternator on a SB?

From B-Bodies forum...2010 and it mentions the single vs multi-wire connections...
alternator replacement with GM type

As for products.. well.. you're going to be a little hard pressed to get a straight answer. For every "yeah its the best!"... you'll get a "man, that thing is a POS!" on here.

Just read and make you're own call.

As for what you posted at CBODY67... dude has been around a long time and is very helpful.. asking questions is what we do... go easy on the snappy answers... lot's of guys here are very happy to help you if you treat them with common respect.

Good luck.

 

[Welder guy]

RockAuto | All The Parts Your Car Will Ever Need A 2010 grand caravan 4 L has an even better alternator . It’s a side post. It stays away from your valve cover. And it’s 160 amp. Not sure if the link works, but you have a picture. Both alternators are externally regulated.

 

[James Romano]

where did you source the mounting brackets?

 

[Knebel]

Im gonna chime in as I have the same alternator and basically the same setup minus "convertible". Sniper 2, 2 fuel pumps, 2 fans, ac and so on

I idle around 900 and usually have 14volts charging, they only drop to 12v at idle if I turn on the blower motor or AC(which I i think has probably a ton of resistance and is on the way out)

Could it be that you have a diode out or something else going on with the alternator?

 

[Knebel]

yes, but amperage equals cooling power. Never ever go by advertised CFM as those numbers are a lot like LED Lumen numbers, all over the board and never equal true LUX numbers.

Yeah I got scammed by FF Dynamics, huge number fan put out less that a spal with half its rating. They were snotty to me and told me all their fans are tested freeflow on a bench at 16volt. So their 3800cfm rated fan was more like 1100cfm in the real world. The spal (tested with restriction) was rated 2200cfm and had about 15mph more windspeed through the radiator!!!! Now i run 2 mishimoto that combine about 3400cfm

 

[Jengel451]

CVF brackets. I did the full conversion kit. After more research I found out the small housing units won't work with an 8 rib pulley without some machine work. Back to the 10/12si unit.

CVF only has brackets for the round/square backs or GM 10/12.

I suppose it's possible I have a diode out. Unfortunately tuff stuff won't warranty it since I swapped the pulley. Thing has less than 1000 miles on it.