High Output Mitsubishi Alternator

[Racer X]

Ok, since I'm scared to death of the run of the mill reman's at AutoZone at the like, I asked a local rebuild shop (a very reputable one at that) about rebuilding mine as a higher output version. He said that he's done 110 - 120A on these successfully a bunch of times, and gave me a quote of $175 and 4 days turn time.

The car is off the road, so the turn time doesn't bother me at all. The other question (which I forgot to ask him) is whether there will be an increase in output at idle, since I have a UDP on the alternator (and only the alternator. Don't ask me, the car came that way. ), and with the current alternator, the idle output is a bit lack luster.

Any input is appreciated.

 

[jelloslug]

Well you don't get something for nothing by increasing the output. When you rewind an alternator to put out more amps all you are doing is changing the output curve. I won't go into great detail (unless you have designed electromechanical devices before also) but the net effect is that you may have low output problems at low RPMs. Factory alternators are designed with a long, flat output curve that works great from idle up. By rewinding it to increase output the curve becomes sharper by starting lower at low RPMS and peaking higher at higher RPMs. Another thing to remember is that your alternator is never going to output more amps that what the electrical system needs. Just because you have the capability to put out 120 amps does not mean that you will be putting out that much all the time.

 

[Racer X]

3 years EE in HS, and 2 in college. I'm familiar.

I was afraid that something like that would be an issue. Right now, at idle, if I stress the electrical system by running all the accessories, the output voltage hovers around 12v, which is definitely not healthy for the battery. Driving in the rain at night gets real interesting sometimes, especially when the defrosters are running.

 

[jelloslug]

3 years EE in HS, and 2 in college. I'm familiar.

I was afraid that something like that would be an issue. Right now, at idle, if I stress the electrical system by running all the accessories, the output voltage hovers around 12v, which is definitely not healthy for the battery. Driving in the rain at night gets real interesting sometimes, especially when the defrosters are running.

Well that is proof of your old alternator is in the process of taking a dump. Do you need extra electrical capacity? If not I would just have him stick to the stock specs.

 

[Geek SHO]

What if you just swapped in a stock alternator pulley? As far as I've heard, UDP's don't really free up any horsepower (even though they were advertised as +5hp), unless you plan on revving your motor to 8000 rpms regularly. I'm talking out my butt a bit though; I don't actually have UDPs.

 

[SHOspazz92]

What if you just swapped in a stock alternator pulley? As far as I've heard, UDP's don't really free up any horsepower (even though they were advertised as +5hp), unless you plan on revving your motor to 8000 rpms regularly. I'm talking out my butt a bit though; I don't actually have UDPs.

Exactly. I had SS UDP's on my car and they did nothing but let me Rev To 7600 RPM and Dim my headlights. Car ran a tad warmer to.

-Sam

 

[SHOZ123]

I have a single crank UDP and didn't really notice it until I took it off. The little bit of added HP was apparent then.

 

[SASHO91]

Ditto^^^
My rev's are faster, mid-range tq is up, and top end pull is a bit better. No loss in electrical/cooling department.

 

[Eric VerValin]

Yea UDPs definately help, your crazy to think otherwise. I drove stock SHO's for a few years, and UDP's were my first mod. No clue on dyno numbers, but seat of the pants it sure is there.

Also.. UDP's in my opinion will make every accessory you got under there last longer because it simply won't spin as many times in the same amount of mileage.

 

[Eric VerValin]

Hey there...

It just dawned on me... if you have a UDP pulley on your alternator, then its fine. You just need the regular pulley. The UDP's on the accessories will make it turn slower, especially if your still running a stock crank. If you put a stock pulley on it, I bet it would test a little different, at all rpms. :wave:

 

[SHOZ123]

You should look up the available stock pulleys for the alternator. On the Gen 3 there must be at least 6 different ones.

http://www.wai-wetherill.com/wrs/wrschicago.cfm

 

[brandon mitchel]

Having an High output alternator would give your vehicle additional power right? That would be perfect on off-road vehicles.

 

[SHOtime2511]

Having an High output alternator would give your vehicle additional power right? That would be perfect on off-road vehicles.

Necro.