I'm in the process of changing the fuel pump . I'm thinking about changing the alternator too since i have to take it off to get to the fuel pump. What's the most powerful alternator I can run on the stock wire gauges? I'm looking for b4b (bang for the buck) solution.

The common misconception is that the alt drives an amount of current. That is not true.
you can put a 2000 amp alt on any car and the car will not burn up.
it is based on the draw the car needs.

As for bang for your buck, the 2 field 89 new yorker is a 74 or 78 amp alt you can pick up at any parts store for 50 bucks.

There was an article about this not that long ago,look in the search for it. Will it fry my wiring/gauges/etc.on 7-21-16

If things are OK now I would suggest leaving it as is & concentrate on the issues that need to be dealt with. If you pull/clean the bulkhead it will take care of most any potential electrical issues & never use the alt to charge a depleted battery (use a regular battery charger). Otherwise as said the 78 amper is the most powerful stock one except for the big 100 amp beast with the fan blades behind the pulley & it has special bracketry & is heavy but is a good piece. the 78 amper has a thin stator so a slight fore/aft mounting adjustment is needed (washers/spacers)

never use the alt to charge a depleted battery (use a regular battery charger).

While I tend to agree without supporting evidence, fact is that likely 99 percent of those of us who ever had their car jump started are guilty as charged.

As noted just yesterday in a posting in response to a thread on this forum, I did exactly this. Battery on my Challenger was almost completely discharged(11.3) volts, jumped with a lithium battery pack, drove off once car was started with the amp gauge pegged for the 1st 15 miles as the gauge slowly returned to the center.

Yes admittedly this fear was at the top of my mind as I silently urged the amp gauge needle to hurry up and find its way to its natural home.

Checked battery when arriving back home, meter showed 12.9 bolts. Today I will be analyzing to find why the fairly new battery self discharged as the car set for 3 plus weeks with the only draw being the tick tick dash clock.

At the same time tho the wiring is usually sized for the stock alternator. If you need a bigger alternator you're going to be pulling more current then the wiring was designed for so you should be using bigger gauge wiring to match. But if someone is just upping the size of their alternator for the hell of it then it doesn't matter.

If you do the amp bypass, run a large wire directly from alternator to battery relay, you won't have to worry about the stock wiring carrying the load.

Battery relay?


You realize that all electrical loads are, by design, supported by the alternator when the engine is running. All your "trick" does is feed the battery direct, everything else still pulls off the stock wiring and now you've severely increased the load on the wiring from the battery to the fuse box. Prior to your "trick" that load came from the alternator output to the fuse box. This is a poorly thought out "cure" for a problem that shouldn't exist.

I got 2 cars with these alternators, one since 2005. They are stock cases nothing special on the outside and cost about 150 bucks I think? I really can't remember somewhere around there.

Is it worth it? Yea I think so because they charge better at idle.

One my cars have stock wiring and AC that is why I wanted a up graded alternator for at night during the summer with the AC running. My lites stay more steady now at idle or low speeds.

No trouble out of either alternator so far, one since 2005.

Good catch, it's actually the starter relay.
Nice to have someone with plenty of free time to clear up important things.

http://www.allpar.com/history/mopar/electrical.html

Stock wiring can handle the stock loads.
Any new parts, electrical fuel pumps or fans, should also be run directly off alternator through a relay.

I have the same one, double pulley, challenger1. Just received and waiting for another part to install on my engine. Trying to get all engine stuff on my engine after paint

I hope your happy with it. I think you will be. Good luck on your motor build.

My motor in 05 and it is still in the car just like this. I haven't taken anything off of it since I don't think? except I went with stock painted valve covers before it went into the car.

Some spare parts I threw together into this 318 challenger.


Donut cutter before Woodward last summer 2015.

I wasn't able to find this 78 amp alternator. Anyone have a link to one?

This is am excerpt from the link someone posted earlier.

"If your original alternator was 35 amps or less, we also recommend that you change the ammeter wiring to a thicker gauge. This will allow the charging system to use the extra amps more efficiently without having to worry about overheating or melting your existing ammeter wiring harness."

But you guys are saying if I put the 78 amp alt in I won't have to worry about melting wires, right?

I run the chrome unit like Challangers.Been in th 65 since 2000.No problems ever but I dont have much draw.My kid uped the alt in the 62 300 when he had it went from 35 to 65.ran it for almost 15 years.no problems and he ran a big stereo and hi output headlight but they were halogens like in my 65.Alt wont usually creat a problem unless you have lots of after market add ons.I do bypass the amp meter as they were bad even new.A larger alt and replacing the points reg with the solid state makes idle lighting better.Rocky

correct. clean the bulkhead male/female brass terminals well especially the 2 main in/out circuits (4 brass terminals)/clean large batt cables including ground path (batt to block/block to firewall) and keep the ammeter needle close to 12 O'clock.

Mopar electronics, what me worry?

BTW here's my current alternator, just want to make that it is the 35amp version. Is there a way to see that from the attached pics?


https://drive.google.com/file/d/0B8IgeG75F_MIOVhEYVBOdk1DM0U/view?usp=drivesdk

https://drive.google.com/file/d/0B8IgeG75F_MIRjFFa21aN0ZEVzA/view?usp=drivesdk

Me too, Challenger1. I think I know where the bracketry and everything else came from on your car. It sure looks good! I have everything as you do on your car. I just have to get working on it when I get back home. Oh, the list is looong for things to do

http://www.powermastermotorsports.com/mopar2.html

the OE 78 amper is one of three alts listed for an '85 Diplomat

Find an old 100 amp Leece-Nevill from a mid 70's police car,have someone go through it and it will bolt on and meet all your requirement and then some.They are not common anymore but still out there or you could buy a new one for just under $200 if you want to spend the money.

Something to think about. What the other people said is true about the car just using what current it needs, BUT, if you have problems anywhere in the wiring like corroded connections and so forth that big alt is just going to feed what ever the bad spots need to get what they want, which leads to overheating and a fire possibility. Let me give an example. I have a 75 model motorcycle that the contacts inside of the ignition switch were pitted or corroded or something bad, cause when I gut to a high enough RPM it would draw so much current that the solder joints on the back side of the switch would melt and the wire would fall off. Just a thought.

I guess the success of the "trick" varies by how you wire in a relay. Pretty simple to wire a relay in so the relay charges the battery and the fusebox only carries the rest of the load.

Personally, I don't use a relay - pretty easy to get the same results without using a $30-40 relay. You simply split the alt output to feed both the battery and fuse block, not the battery through the bulkhead and back out.

And I agree - the problem shouldn't exist - pretty stupid for Mopar to charge the battery through 2 bulkhead connectors and interior wiring.

I sell a lot of the 6 and 8ga wire around cables. How you wire it is important.

I think the poster was talking about the starter relay and termed it battery relay.

What size wire is the red coming from the battery and the black coming from the alternator? How is running power from either side going to impair the system?

I tell people, run the wire around cable, bypass ammeter and leave EVERYTHING else, factory wiring, in place.

Running a 50+ amp alternator with the factory wiring/bulkheads/ammeter is plain not smart. The bulkhead will eventually melt regardless of how clean any terminals may be.

Thanks.

Seem to be a lot of conflicting opinions on this. Maybe I should just leave the old one in, at least till I get around to bypassing the ameter.

If he leaves the factory wiring hooked up and just runs another wire from the alt output to the battery the alt will still feed everything in the car like stock which is through the bulkhead to the ign switch side of the ammeter which feeds everything in the car. But now the battery is not getting charged back through the bulkhead and through ammeter and then the bulkhead again out to the starter relay and fuselink and back to the battery.
He would also render the amp gauge from working right.
Course if he eliminated the stock alt output and only ran a wire to the battery then the output current would go to the battery and then go from the battery back through the stock wiring to the starter relay and then through the fuselink and bulkhead through the ammeter in the wrong direction and feed everything in the car.
Myself I would clean the bulkhead connectors or eliminate the alt and hot feed bulkhead connectors and leave the stock wiring in place and maybe upgrade any wiring that might need it and also run another alt output right to the battery. And then put a voltmeter in the car to moniter the charging system. That way the battery will charge through the one new wire you put in and the alt will also supply the car through the stock alt output wiring which would be through the bulkhead to the hot feed on the ign switch side of the ammeter which feeds everything in the car. Ron

Would you guys say this is the most correct way of doing it? (Diagram on top of page)

http://www.madelectrical.com/electricaltech/amp-gauges2.shtml

NO!!!

Is it the best ?? There are better ways to do it but it will work ok. Looks like they are drilling the bulkhead and running soldered splices which I have done on bulkheads to eliminate them. Dont forget to seal the hole up around the wires if you do it that way. And of course your ammeter wont work so you can do like most and put a voltmeter on an ign 1 controlled wire.
I bypassed my amp gauge and spliced the bulkheads on my 63 and then added a voltmeter. But I was not having any trouble. I figured it was a good idea since the car is over 50 years old. Ron

Yeah I think I'll put a voltmeter in there, it's pretty handy.