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  #1  
Old 12-12-2006, 03:59 PM
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Default Alternator upgrade options?

I have a stroked 400 big block in a Dart. I'm thinking about adding some electrical goodies and I feel my alternator is already doing a marginal job at best. At idle with the headlights on my voltage drops and keeps dropping until I rev up. So...

I'm looking for a high power alternator to swap in. What options do I have? What is the cost? Total output? Output at idle? Mounting modifications required?

I'd like something cheap and able to handle power-hungry electric fans, digital gauges, headlights, radio, msd, A/C, and possibly electronic fuel injection in the future. I'd also prefer not to put a GM 12si alternator into the dart for obvious non-mopar reasons.

Thanks!
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  #2  
Old 12-12-2006, 04:08 PM
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One thing that would help is to run the head lights off of a relay. That will take some of the load off of the dash harness and it will also make the headlights brighter.
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  #3  
Old 12-12-2006, 04:16 PM
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Thanks for the input. I've already got the headlights wired through relays. The problem isn't dim headlights as much as it is my aftermarket voltage gauge is reporting voltage drop from 13.3 at cruise to 12ish or even less than 12 on occasion at idle (and this was verified at the battery with a multimeter). I think it is a problem that my alternator can't keep up at idle with the demand my car places on it. With no headlights on, it'll idle at 13.3. It's funny because it is a powermaster chrome alternator(original mopar style), but I don't know the specs on it.
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Old 12-12-2006, 05:32 PM
BJSracing BJSracing is offline
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You could also go to the MP constant voltage regulator.
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  #5  
Old 12-12-2006, 08:11 PM
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Quote:
Originally Posted by BJSracing View Post
You could also go to the MP constant voltage regulator.
I don't think the constant output regulator is recomended for continous use. It may also be tough on the alternator too. A larger alternator would be better. The police cars back in the 80's had a much bigger alternator to run all the cop type accessories. Also the alternators from later model Rams may be a good bet too.
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  #6  
Old 12-12-2006, 09:47 PM
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I doubt a regulator change would do anything.

The voltage isn't dropping because of the regulator. It's because at full output, the alternator can't make enough amperage to maintain the voltage.

In any case, there are a few options.
I believe the highest amperage alternator in the factory case is 78 amps. They are visually differen, in that the windings between the case halves are much thinner than the regular old alternators. I have used them on a few rigs with good sucess, but not with the kind of accesory load being suggested here (fi ,ac , etc)

This denso alternator swap works well
http://cuda66273.proboards23.com/ind...ead=1081309590

Gives better output than any old design, and saves some horse power too.
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  #7  
Old 12-12-2006, 10:52 PM
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You can get the ND alt on ebay rather inexpensive. You can get a 138 AMP in the ND setup and it can be setup to work with the existing charging system. The important thing is to run a new heavy gauge wire from the alt to the battery. This will allow the high current potential to bypass the alt guage and bulkhead connector.

If you do a search, you will find another (rather old thread) that details all of the specifics.
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  #8  
Old 12-13-2006, 07:10 AM
George G. Leverette George G. Leverette is offline
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www.madelectrical.com has some very good information and suggestions on solving this problem. Mad is also a good source for wiring parts, and the owner is quite knowledgeable and easy to talk with.
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  #9  
Old 12-13-2006, 08:40 AM
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www.magnumhp.com Talk to Greg.
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  #10  
Old 12-13-2006, 09:01 AM
a440plus6® a440plus6® is offline
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You can go junk yardin and hunt up a Leese Neville and brkts.....usually only came on cop cars and heavy duty trucks. I have the alt but no brkts.
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  #11  
Old 12-13-2006, 03:16 PM
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Thanks for all the info guys. By far, the Denso swap sounds the best. I think I'll go junk yardin for a used ND unit and hope that I can make the bracketry line up right. That's really the area that worries me the most...

I can't wait to have full power. Maybe it'll fix my pesky missing problem...
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  #12  
Old 12-13-2006, 09:30 PM
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Here is the thread from the tech archives. It's a good read.

Alternator Conversion
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  #13  
Old 12-13-2006, 11:45 PM
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The link I posted was written by dkn19997, same guy who started that thread.

He did a good job of getting it all to fit and work.
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  #14  
Old 12-14-2006, 12:07 AM
451Mopar 451Mopar is offline
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For several performance reasons the Denso alternators are very good, but they cost more and you need some other parts to get then mounted and wired.

One problem with the stock type alternators is they don't have very good low RPM output, even the higher amperage rated ones are still fairly week at low RPM. You could change the pulleys to turn the alternator faster so it will put out more current, but you run the risk of damaging the alternator at high RPM's. FWIW, under drive pulleys make the problem worse.

The Denso alternators are rated to handle 14,000+ RPM, so it is possable to run a 2:1 pulley ratio if you wanted, so these put out more current at lower Engine RPM, partly because the alternator is spinning faster than a stock alternator.

I got a new 130Amp Denco alternator off E-bay from some place that does some type of dual alternator conversion for (I think) ambulances?
Anyhow, I think I paid under $100 for the alternator.

The first thing I had to do was replace the pulley with a V-Belt pulley. This took a little research at a local alternator shop, and cost $20 for a pulley. The next thing you need is the molded field connector plug. There is a couple sources for these, but plan on spending around $10-20 for the connector plug. I think you could connect the alternator without it, but I wanted the correct connector.
Then you will have to fabricate an alternator mount. On my 400 block, the Denco alternator is so thick that it would have been right agnist the block, so I moved the mounting point lower where the fuel pump would have been.
Last is wiring. Wiring the field is pretty simple, just like stock, but you don't want to run all that new power through the stock wiring harness/bulkhead connector, so you need some 8AWG wire to run from the alternator to the Battery. The new wire should also be the one supplying power to relays for the electric fuel pump, fans, etc. You can then hook the stock alternator wire to the alternator (creates a parallel current path) to simplify the wiring, but the alternator gauge won't read right so use a voltage gauge if you want to monitor the charging system.
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  #15  
Old 12-14-2006, 07:03 PM
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The molded field connector plug isn't really needed. For that specific alt, you can use a pair of small terminal connectors. They are about 20 cents. If you go with a later year, they use a pair of studs with nuts to hold the wires on. Again, just a pair of cheap connectors.

You don't need to overdireve the ND alt at idle. They put out more than enough current with the standard pulley.

The last time I replace the alt in my '96 Ram, they had to swap the pulley onto the new alt, as the new alt had the V-groove pulley. This was a 120 Amp alt. Most auto parts stores don't really care if the old alt and the new alt are the same. So, you might be able to take a late '60s or '70s alt in and exchange it for a rebuilt 125 Amp unit with a lifetime warranty.
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  #16  
Old 12-14-2006, 10:45 PM
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Do this. Cheap effective. and it fits in the original Mopar alternator case. None of that "I had to mod the bracket with......."
Pick one. 80 or 105 amp. Check if you have a round or square back alternator. Purchase accordingly.
http://www.alternatorparts.com/chrys...grade_kits.htm
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  #17  
Old 12-15-2006, 07:05 PM
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Quote:
Originally Posted by swingin72 View Post
T I think I'll go junk yardin for a used ND unit and hope that I can make the bracketry line up right. That's really the area that worries me the most...
Fear not grasshopper!! it fits without breaking a sweat. at least on a 440 it fits. the only mods I did was to cut one factory spacer and had to put a nut on backside of adjust bolt. that's it as far as bracketry.

I cannot beleive people sell kits for this when no kit is needed. I have gotten into it over at moparts with someone there who told me that some arc angle would not be right bolting the denso in, but it's been a long time since I did this swap and haave had 0 belt problems, all it well.

I have concluded that this alt stands a good chance of fitting small blocks too. I figure that the s/b alt that came off my 318 bolted right to my 440...so.... the only fly in that ointment may be clearance to the back of the block. it's tight on big blocks.
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Old 12-15-2006, 07:10 PM
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Thanks DKN! That's great to hear since I am limited in space and tools in my 1-car garage that comes with my apartment.

I'm glad to hear the alternator has lived a long time since you swapped. That makes me hopeful for good results. Thanks a bunch for writing up that initial post in the archives.

Did you ever find the proper field connector? Do you have a source for it?

Thanks!
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  #19  
Old 12-15-2006, 07:39 PM
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pretty cheap too:

http://cgi.ebay.com/ebaymotors/96-00...68210680QQrdZ1

egouge is a bit dry now, but usually several on there that will do. the 90 amp units go for dirt cheap, sometimes 30 bucks.
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  #20  
Old 12-15-2006, 08:36 PM
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Quote:
Originally Posted by ehostler View Post
Here is the thread from the tech archives. It's a good read.

Alternator Conversion
That thread was in 2002?!?!?! Urghhhh, I bought that 135 amp alternator on e-Bay back then and I still have it, in the box, sitting on a shelf in the workshop....

It's a great thread though.
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  #21  
Old 12-15-2006, 10:52 PM
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Quote:
Originally Posted by dkn1997 View Post
pretty cheap too:

http://cgi.ebay.com/ebaymotors/96-00...68210680QQrdZ1

egouge is a bit dry now, but usually several on there that will do. the 90 amp units go for dirt cheap, sometimes 30 bucks.
Thanks for the link, DKN. I wonder if that's the 90A or the 130A version.

BUT, what I was really asking you is if you ever got the proper electrical connector for the field wires and, if so, where did you buy the electrical connector
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Old 12-16-2006, 04:05 PM
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Yes, I did get one...I got it from member "chargerdan" I forget where he got it though. at the time, it was a brand new connector, as previous models used two threaded posts. Now, 4 years later, I would imagine you could go to the local chrysler dealer and ask for a field wire connector for a 2002 one ton ram van.

again, not all of the denso alts we are talking about even have that connector. also, my ghetto rig worked fine and if dan had not gone out and done the research to find the connector and basically gift wrapped it and sent it to me, I would be still running my bent up connectors.
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  #23  
Old 12-16-2006, 05:05 PM
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440ram did that upgrade also cure the low output at idle issue? If it did it sure looks like a worthwhile alternative to swapping units.
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  #24  
Old 12-16-2006, 07:07 PM
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Those kits rarely help the idle problem. Most of those kits tend to make the idle problem worse.
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Old 12-16-2006, 08:43 PM
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Quote:
Originally Posted by dkn1997 View Post
Yes, I did get one...I got it from member "chargerdan" I forget where he got it though. at the time, it was a brand new connector, as previous models used two threaded posts. Now, 4 years later, I would imagine you could go to the local chrysler dealer and ask for a field wire connector for a 2002 one ton ram van.
hey kevin,
4 years ago, i purchased the proper field connector pigtail for that particular denso alternator from a local auto electric business. it was my last chance, as the dealer was no help. however, as you have said, it should be pretty easy to source at the dealer by now. i think they cost about $10 - $15 at the time.

it was a weatherpack-sealed fitting, if i remember correctly???
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Old 12-17-2006, 12:34 PM
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yep, black connector with green ribbed rubber molded in to seal it. How are you dan? your charger is in mothballs due to school or something, right? If that's the case, I hope you get it out soon.

I have been putting more stock looking and functioning components back on my charger in the last few years.....and I am driving it a lot more. especially with my 130 amps of P-O-W-E-R. In the immortal words of AC/DC:

"FIRE!!!"
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  #27  
Old 12-19-2006, 02:49 PM
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hey kevin
yeah, my dodge is still in mothballs back in oregon. i really miss her, as most of what you see cruising the streets of so-cal are first gen. mustangs. ack. the only thing that saves a moparite like me is the cpw club fall and spring fling events -- which are awesome mopar shows.

btw, are you utilizing remote voltage sensing with your upgraded charging system?
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  #28  
Old 12-21-2006, 10:09 PM
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that's a big negatory dan!! I still have the drawing you sent me, though. I may do it now. I just did the amp gauge bypass, and that was only because I took the cluster out for an at home refinish. what do you think?
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  #29  
Old 12-21-2006, 10:13 PM
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here it is, all done in the comfy confines of my house
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