Bigger Alternator question

Posted By: mjb765

Bigger Alternator question - 10/21/12 01:35 AM

I have a 69 Super Bee and since I am planning on adding A/C and upgrading headlights and possibly a bigger amp for the radio I was thinking of a 1 wire powermaster alternator. Rather than go to the 75Amp, I was thinking of going bigger--just in case I need it. Can I go to a 140A unit and do the following: bypass the factory ammeter and install a voltmeter,run an 8 ga wire to the starter realy from the alt using a 12ga fusible link, and bypass the bulkhead connector completely and feed the interior with a wire coming off the starter realy where the alt connects? That should handle any charge load and still supply the rest of the car with power.

Posted By: ahy

Re: Bigger Alternator question - 10/21/12 02:16 AM

That sounds like a good plan. The 75 amp squarebacks are pretty limited in idle output.

Two comments. 8 guage with 12 guage fusible link would work. 6 guage with 10 guage fusible link would be better with a 140 amp alternator.

Also the Powermaster 140 amp can be a tight fit. In some applications, the output stud wants to hit the head. BB with stock heads is probably OK. SB is probably OK. BB with aluminum heads was no-go for me (BB w AC).

The AC bracket setup has fixed pivot and swing arc and is not as adaptable as the non-AC brackets.

I ran the 75 amp for a while, but with a big fuel pump, AC and lots electronics, it couldn't keep up very well so I went with the factory "high amp" option. Its heavy but works very well.

Attached picture 7429177-IMG_2201.jpg

Posted By: mjb765

Re: Bigger Alternator question - 10/21/12 02:46 AM

Thanks for the info....one other question now that I saw your pic..are those Mopar perf valve covers taller than stock?? I have roller rockers that won't fit under stock covers so the previous owner put on stamped steel Moroso covers which I don't like. I was told your covers are taller, but Summit sells them and describes them as stock height....

And 2 other questions..I think on a 1 wire alt, the fusible link goes by the alt output stud--correct?? And if I am going 6 gauge from the alt to the starter realy, should I go 6 gauge from the starter relay to the battery?

Posted By: ahy

Re: Bigger Alternator question - 10/21/12 03:05 AM

On the valve covers, I've never compared MP cast to stock. I'm running Comp "pro magnum" rockers (investment cast alloy steel) which fit w/o problem.

Posted By: mjb765

Re: Bigger Alternator question - 10/21/12 12:52 PM

and what about

And 2 other questions..I think on a 1 wire alt, the fusible link goes by the alt output stud--correct?? And if I am going 6 gauge from the alt to the starter realy, should I go 6 gauge from the starter relay to the battery?

Posted By: RapidRobert

Re: Bigger Alternator question - 10/21/12 02:18 PM

Quote:

And if I am going 6 gauge from the alt to the starter realy, should I go 6 gauge from the starter relay to the battery?

Yes the smallest wire in the alt-relay-batt circuit makes the whole path in effect a smaller wire but I'd think your relay to batt cable right now is larger (smaller gauge) than 6 gauge??? If not then yes change it so you have 6 gauge all the way from alt to batt

Posted By: Dodgem

Re: Bigger Alternator question - 10/21/12 02:41 PM

I bought the 120 amp package from Mancini
http://chucker54.stores.yahoo.net/delialbrpk.html

Ground one field wire and your good to go. It charges like crazy at idle
mine is the same brackets but slightly different

and mine has dual belt set up if needed

Posted By: ahy

Re: Bigger Alternator question - 10/22/12 02:25 AM

The Denso 120 A alternator is great and the Mancini package looks nice. Only problem is the OP plans to run AC which requires different brackets and extra bracing. I don't believe the Mancini setup is made for AC.

I think the best bet for "with AC" is to try the 140 A Powermaster. If it fits great. If not make sure you buy it from somebody who will take it back. Otherwise, run the 75 amp squareback. If extra loads are AC and a bigger amp the 75 should do it. Where it really struggles is with heavy continuous loads like electric fans or big fuel pumps.

Rumor has it Powermaster is coming out with a high performance alternator that mounts in place of the squareback... we'll see.

Posted By: mjb765

Re: Bigger Alternator question - 10/22/12 02:54 AM

Quote:

The Denso 120 A alternator is great and the Mancini package looks nice. Only problem is the OP plans to run AC which requires different brackets and extra bracing. I don't believe the Mancini setup is made for AC.

I think the best bet for "with AC" is to try the 140 A Powermaster. If it fits great. If not make sure you buy it from somebody who will take it back. Otherwise, run the 75 amp squareback. If extra loads are AC and a bigger amp the 75 should do it. Where it really struggles is with heavy continuous loads like electric fans or big fuel pumps.

Rumor has it Powermaster is coming out with a high performance alternator that mounts in place of the squareback... we'll see.

I guess I will give Powermaster a call and get their thoughts on the 140A with A/C question...and I will also ask about the high performance squareback replacement.

Posted By: 71rm23

Re: Bigger Alternator question - 10/22/12 11:02 AM

Quote:

Quote:

The Denso 120 A alternator is great and the Mancini package looks nice. Only problem is the OP plans to run AC which requires different brackets and extra bracing. I don't believe the Mancini setup is made for AC.

I think the best bet for "with AC" is to try the 140 A Powermaster. If it fits great. If not make sure you buy it from somebody who will take it back. Otherwise, run the 75 amp squareback. If extra loads are AC and a bigger amp the 75 should do it. Where it really struggles is with heavy continuous loads like electric fans or big fuel pumps.

Rumor has it Powermaster is coming out with a high performance alternator that mounts in place of the squareback... we'll see.

I guess I will give Powermaster a call and get their thoughts on the 140A with A/C question...and I will also ask about the high performance squareback replacement.

MJB785....Post your findings if you call, please. I'm interested in knowing. Thanks

Posted By: mjb765

Re: Bigger Alternator question - 10/22/12 07:50 PM

Quote:

Quote:

Quote:

The Denso 120 A alternator is great and the Mancini package looks nice. Only problem is the OP plans to run AC which requires different brackets and extra bracing. I don't believe the Mancini setup is made for AC.

I think the best bet for "with AC" is to try the 140 A Powermaster. If it fits great. If not make sure you buy it from somebody who will take it back. Otherwise, run the 75 amp squareback. If extra loads are AC and a bigger amp the 75 should do it. Where it really struggles is with heavy continuous loads like electric fans or big fuel pumps.

Rumor has it Powermaster is coming out with a high performance alternator that mounts in place of the squareback... we'll see.

I guess I will give Powermaster a call and get their thoughts on the 140A with A/C question...and I will also ask about the high performance squareback replacement.

MJB785....Post your findings if you call, please. I'm interested in knowing. Thanks

According to Powermaster the 74191 squareback will mount in stock location and is now putting out 60-65A at idle and closer to 90A at cruising speed. The 140A may need different brackets, but he wasn't sure. He was not the sharpest knife in the drawer....But I think I can stay with the 74191 for my application.

Posted By: 71rm23

Re: Bigger Alternator question - 10/23/12 11:36 AM

Thanks mjb765 for the info

Posted By: Jeremiah

Re: Bigger Alternator question - 10/23/12 06:06 PM

I run one of these and it work great:

http://www.summitracing.com/parts/TFF-7509RFSP/

They make them with a two groove pulley as well.

Posted By: Cab_Burge

Re: Bigger Alternator question - 10/24/12 05:29 PM

Quote:

I run one of these and it work great:

http://www.summitracing.com/parts/TFF-7509RFSP/

They make them with a two groove pulley as well.

Me to