How to: Alternator upgrade - 4G, 3G large or small case?

[2000StreetRod]

220 amp alternator

The 220 amp alternator I purchased from Eagle Auto Electric for $170 arrived today. The physical dimensions: case diameter, depth & bolt pattern, pulley diameter, and terminal connections are identical to my stock 130 amp alternator.

If you look closely you'll notice the assembled depth of the 220 amp is slightly greater than the 130 amp due to the increased gap between the front and rear sections. You may also notice that the rear cover is slightly pulled out between the two connectors like it got caught on something. It was well packed so I doubt it was damaged during shipment. I'll just use a large C clamp to squeeze it back into position.

It will probably be at least a month before I get a chance to test it because of my in progress supercharger installation. If it works then I'll probably grind the "shoulders" off the insulator at the charge terminal to allow rotation of the mating charge cable terminal.

 

[krispy97xlt]

I find it a little strange that the pulley diameters appear to be the same.

Back on my 97 4.0 SOHC I was searching for a high output alternator. I found a guy by the name of Dom Iraggi that custom wound one for me.

When I installed it I found that I needed a shorter serp. belt due to the diameter reduction of the pulley to overdrive the alternator.

I had a friend that worked at an alternator shop at the time who was a bit miffed that I decided to use "some online guy" instead of him. He told me that it was impossible to get 200+ amps out of this housing. He offered to test the alternator that I received from Dom.

When we bolted it to the test rig and applied an electrical load to the system it stalled the electric motor that was being used to spin the alternator. He said that he had never maxed out his test rig and that this was easily a 200+ amp alternator.

Before you modify the alternator you have perhaps you should get it checked out to see how it performs.

 

[2000StreetRod]

smaller pulley

I was also a little surprised that the pulley diameter was the same as stock. As a matter of fact, the installation instructions stated that if the pulley diameter was different from stock to swap pulleys. Many aftermarket higher than stock capacity alternators achieve much of the increase by increasing the rpm over stock by reducing the pulley size. The other means is to increase the windings and the rectifier capacity. This one appears to have more windings stuffed into it.

Having the alternator output tested is probably a good idea. Maybe I'll take it to the shop that said they no longer have access to higher current windings.

 

[2000StreetRod]

alternator test

A new O'Reilly's opened nearby. I was in there this morning picking up some items for my M90 installation and noticed the free alternator test sign. I asked about it and was encouraged to bring mine in even though I wasn't a potential purchaser of one. I came back about 30 minutes later with the 220 rated unit. They had an Auto Meter machine that tests alternators and starters. Unfortunately, the largest capacity altenator in their database for the 4G case was my stock 130 amp unit. My 220 amp unit passed the voltage and rectifier tests but it was not fully loaded.

Later today I called a shop that rebuilds alternators and learned they had the same machine but I was told about a shop out in the country that could probably test my unit under greater load. I called the owner and he said he could load it up to 200 amps so I'm going there in the morning.

 

[2000StreetRod]

alternator test results

. . . Before you modify the alternator you have perhaps you should get it checked out to see how it performs.

Very good advice! I spent about an hour at Carolina Alternators talking with the owner Tom Coker and learned a lot. His tester loads the alternator under test to a maximum of 200 amps. The tester was built by D V Electronics of Canada and is the same company that manufactures alternator testers for OEM alternator manufacturers. My stock (original) 130 amp alternator with approximately 160 K miles developed a peak of 150 amps. I learned that OEMs typically rate their alternators 15% less than peak to be conservative. The so called 220 amp alternator from Eagle Auto Electric peaked at 160 amps at an alternator speed of 9,000 rpm. I have since requested return shipping instructions for the alternator.

It turns out that Tom used to have a substantial alternator upgrade business in Spartanburg but sold his company after tiring of driving from Easley everyday and dealing with employee issues. He seems to remember being an Explorer Forum vendor about ten years ago. Now he is happy with a single "employee" shop and a very short commute and performing repairs. I persuaded him to consider upgrading 4G alternators to 200 amps and hope to be his next customer.

 

[2000StreetRod]

battery terminals & ebay learning experience

Well I thought I was done with the battery wiring and connections. The assumed final configuration is shown below.

Unfortunately, I found out the battery terminals are unsuitable when I tried to tighten them on the battery posts. According to standards the positive terminal bore is larger in diameter than the negative but the bore is not tapered to match the shape of the battery post. It looks like a parallel bore with a small chamfer (bevel) on the bottom edge. Consequently, it only contacts the battery post at the bottom edge. When I tightened the clamp bolt in an attempt to increase the contact surface area the terminal broke. Just before breaking, even though the bolt was very tight, I could still easily rotate the terminal with my hand. Both terminals are bored the same way so neither will get tight on the posts. Since I cut and shaped the wires to match the terminals I will have to find something similar to replace them.

Begin ebay rant: I purchase things on ebay because I can't find something suitable locally. It is my experience that most of what is advertised on ebay are cheap "knock-offs" of a quality product. They are pictured and manufactured to look like another product that works and are priced at a slightly lower cost. They are manufactured in China with no regard for quality or functionality. Most of the ebay "stores" are merely resellers with no knowledge of what they're selling or its application. They may have never even seen their product. They just buy from a supplier at a low cost and sell to a buyer at a profit. Often I ask specific questions about a product before purchasing. The answers I receive are frequently very general because the seller has no specific knowledge of the item. ebay sellers don't worry much about reputation because they have very little invested in their "store" and they have a huge potential market. They often use photos and part numbers from a quality manufactured item to dupe buyers into purchasing their inferior item at a lower cost. They are not penalized for selling junk because when an item is returned for refund the purchaser has to pay shipping. Many ignorant purchasers may never be aware that the item is inferior and not return it. For example I purchased an advertised 220 amp alternator that when tested (on a machine that loads the alternator) only produced a maximum of 160 amps (just 10 more than my stock 130 amp alternator).

I always attempt to identify reputable (name brand) products with part numbers for online purchasing. Before buying an ebay listed item I determine if the part has the identified part number and is manufactured by the reputable company. If not, I look elsewhere. I advise all to do the same. End rant.

 

[2000StreetRod]

My new 240 amp alternator

Today I picked up my new 240 amp alternator from Carolina Alternators.. Tom Coker assembled a prototype from parts available to him from various suppliers he has used in the past. It has a new 200 amp rotor winding, a new 240 amp stator winding, and a new load response internal voltage regulator assembled in a new case with a new stock size pulley.

We were both pleased with the test results. Tom's machine has a load capacity of around 190 amps. My alternator output voltage was 14.2 volts with no load and only dropped to 13.8 volts at full load of 190 amps. Tom rebuilds and tests fire engine alternators rated at 275 amps and said my alternator voltage drop was less than the 275 amp fire engine alternators. He said he is willing to build 240 amp and 200 amp alternators for Explorers having 3G (large or small), 4G or 6G (large or small). He does not want to maintain the parts in stock so Explorer Forum members will have to be patient for their units. It only took him about a week to get my parts and assemble the complete unit.

 

[2000StreetRod]

suitable battery post terminals

As I posted earlier, the Aapex 0/1 2 4 8 awg Gauge GOLD CAR HD BATTERY Terminal PAIR Positive Neg SET
I purchased on ebay was junk. I found a suitable negative terminal replacement (Audiopipe gold finish multi Feed Battery Connection System BT-705N) at Carlton Custom Motorsports in Greenville.

They didn't have the positive terminal (BT-705P) so I ordered one online.

 

[Anime]

The Audiopipe terminal design and even the packaging makes me think they are made by Stinger/AAMP for them, as they appear to be a ripoff of the Stinger SPT53102 terminals. Just looks like a classier/upscale satin finish.

They are good for show, but terminals with those allen set screws for wire attachment just don't seem all that secure without some loctite on the threads. It's also usually not a good idea to use showy terminals with lead-acid batteries as the corrosion usually eats them even more than regular coated copper terminals.

 

[2000StreetRod]

thread lock

Thanks for the heads up. Using thread lock is a good idea and I'll probably do that after I snug them up a couple of times. I wasn't interested in looks and I agree with your comments. However, I couldn't find any other product that provided the wire connections I needed. I'll look into the Stinger terminals.

 

[2000StreetRod]

Modifying charge terminal

Using a hack saw I cut off the alternator charge terminal insulator shoulders to increase the metal contact with the charge cable.

For the final installation of the 240 amp alternator I installed 3/4" dia. split convoluted flexible conduit on the charge cable.

Unfortunately, I won't be able to try out the new alternator until January when I finish my M90 installation.

 

[2000StreetRod]

250 amp slow-blow mega fuse

After talking with Tom at Carolina Alternator I learned that the real purpose of the mega fuse is to blow when an internal short in the alternator occurs. Sometimes the rectifiers will fail in a shorted mode instead of an open mode. We decided that a 275 amp mega fuse would be appropriate for my 240 amp alternator. However, I was unable to find one in that size so I settled for a supposedly rated 250 amp slow-blow mega fuse. Here it is installed next to the battery junction box.

As soon as I get my engine to idle properly with the M90 installed I'll measure the output voltage. I'll never be able to determine the actual maximum current capability.

 

[colintrax]

How much is he selling those alternators for?

 

[2000StreetRod]

selling price?

I don't know what he's charging for the 200 and 240 amp alternators. Mine was kind of an experiment to see what he could do with parts available from various suppliers. He may have given me a break on the cost or he may have charged more because of the research he had to do so I'm not going to post what I paid. Also, I didn't have to pay for shipping. My guess would be about $1 per amp plus shipping. I think he could also build a 180 amp alternator but it wouldn't be worth the cost just to upgrade because the stock 130 amp alternator will put out 150 amps. However, a 180 amp unit might be worth the cost to replace a failed stock alternator. I suggest that you call (864-269-6888) or email (tom.carolinaalternators@charter.net) to get current pricing.

 

[vroomzoomboom]

just to blow some dust off a older thread i also needed a larger alt (running bigger fuel pump, electric fans, meth pump, stereo) and searched high and low for a 200amp (might be overkill, but i can add stuff later and not worry about maxing the alt). i found a place called tuff stuff (http://www.tuffstuffperformance.com...61.1373823-1998-ford-explorer-v8-5-0-302.html). they are based in ohio. called them and talked to bud riser (who ironically knew exactly where i lived, and also knew my ex girlfriends family lol). he had told me they have a 4G alt and build them new when ordered with new parts inside. they can come cast, powdercoated black, or polished finish. you can either find a dealer on their web page, or order them using summit racing.

 

[BruceExploder]

Who has upgraded their alternator recently? Bumping thread