Alternator upgrade?

[dmopar74]

73 225 duster. After adding a stereo system and AC to my car my alternator is not happy. I would like to upgrade to an alternator that puts out more amps at idle and perhaps go one wire. I have bypassed the ammeter and added a 10g charge wire from the alt to the battery already.

 

[RedFish]

I remember when changing pulley diameters was the solution to your problem. I dont know if todays adjustable regulator would help or not.

 

[MadScientistMat]

An adjustable regulator won't help; at idle it will be locked fully on. I'm running an alternator intended for a 1989 Ram truck with a 318; it's a 100 amp unit that is close to a bolt on for a slant six.

 

[67Dart273]

73 225 duster. After adding a stereo system and AC to my car my alternator is not happy. I would like to upgrade to an alternator that puts out more amps at idle and perhaps go one wire. I have bypassed the ammeter and added a 10g charge wire from the alt to the battery already.

Bigger is not always better. If you dig deep, and don't ask me where, there exists shaft RPM vs output curves for alternators. There is one smaller Mopar one in particutlar, I think 47??? that puts out more power at lower shaft speed than some of the larger ones.

Newer units Denso, etc do seem to be better. As noted, tho, pulley size is important. You may want to bump the idle RPM up a bit, if you can. A 10ga charge wire may not be enough.

Also many installations used an idle solenoid to boost idle speed when AC is running. Just hook it to the clutch wire

 

[CrazyBlaize]

It’s actually quite surprising how much of a difference bumping up your idle speed makes, and 67 dart has a great idea with the idle solenoid, that shunt wire will also help a ton,

 

[Murray]

Do you currently have a square back Mopar alternator?

 

[dmopar74]

Do you currently have a square back Mopar alternator?

Yes, I did order a powermaster 95 amp and will upgrade all associated wiring. Whether that solves my problems will be determined

 

[67Dart273]

Yes, I did order a powermaster 95 amp and will upgrade all associated wiring. Whether that solves my problems will be determined

As I said, tho, bigger is not necessarily the answer. More current at lower shaft speed is what you are after.

 

[dmopar74]

As I said, tho, bigger is not necessarily the answer. More current at lower shaft speed is what you are after.

I did read that the powermaster puts out much more amperage at idle. Figured between a 1000w stereo, added AC with a condenser fan, and in cab AC fan that the extra amps were welcome.

 

[Bewy]

The pulley ratio [ crank & alt ] need to be factored into the mix to determine if the output is sufficient at 'idle rpm'.

 

[Dave999]

I have run a 50 amp hitachi LT-150 with a mopar regulator it worked very well had to make my own bracket.
1 wire...regulator in, ignore the other connector its a test point, 1 fat wire to battery

if you wanted 1 (2) wire you'd need its sister LR-150 R meaning internal regulator.
these came on the ever reliable datsuns from mid 70s until early 90s and are also used on a range of small chevys

i chose the LT because it was cheap and because it in theory consumed not much more power in the field circuit than what was there meaning compatibility with the mopar regulator i had
and at 50 amps it only pegged the ammeter to the end stop for a few seconds after start.

since removed it and put in a kubota 40 amp denso. because i don't want to bust my perfectly functioning ammeter.

way smaller and lighter. these have an internal regulator, for US mopars mancini does a bracket kit...i had to make my own.

2 types: 2 wire and 3 wire, you have a 12 volt in, an idiot light connector and a 3rd connection, a third wire which you don't need. if it is "sense" connect to battery if it is P its a tacho connection for the ECU on the orginal application. The pin outs are usually shown on a sticker near the manufacturers logo.

if you do not connect the idiot light they do nothing till you hit 2000+ rpm and then once excited, stay working at idle. if you connect the idiot light connector they excite at 750-900 rpm and stay working

15mm shaft with a pulley you can buy a huge range of pulley offsets up to 3/4 inch forward, but its easier to buy 15mm shims in 0.5mm and just shim the pulley to correct any misalignment.

denso comes in 2 configs stud out the back and stud out the side of the rear cover.
the out the side version is better for 6 cylinder cars, so you don't short to the fuel pump, either works on a v8
a real Denso has stylised ND logo pressed into the back cover a licenced copy does not
a cheap chinese copy does not

hitachi hitachi lt-150 - Google Search

denso
kubota denso 40 amp - Google Search

cheap chinese versions of denso in the UK £60
OEM Kubota £80-90
Original Kubota denso Shop soiled NOS £100 Genuine Denso Alternator 12V 40 Amp for Kubota D722 D902 D905 D1005 D1105 Engine | eBay UK

we have guys in the UK running race cars with electric pumps, electric water pumps and ECUs using this 40 amp unit and it manages well enough. walk round the pits of the UK nostalgia super stock guys and you will see this alternator everywhere. The specification seems a genuine 40 amps with no sweat. its not running "on the edge" at full capacity, and they seem to put up with being spun to ridiculous RPMs repeatedly for a 1/4 mile at a time. nobody seized or snapped the shaft in their denso. I'ts been a favorite retrofit- kit car- race car alternator in the UK since they came out as original equipment on the bedford rascal/suzuki carry mini-van in the 1980s/90s Tiny and effective

bigger amp versions with a different case available as well

Dave