MX-3.com

So, this has been on my long list of stuff I'd like to know for far too long.

Does anybody happen to have the weight of both an MX-3 Alt. and a Millenia Alt. on hand? I haven't seen anybody else post on this subject at all, nowhere close...

I never actually weighed them but I've had both side by side on my parts shelf in the past and they're very similar. I wouldn't think there's much difference between them.

Well.. it has to have more windings no?

So it will weigh more. The rotor/stator will be the main weight, the housing is aluminum and weighs almost nothing.

Either way, this upgrade is useless unless you can draw more than the alty puts out (60A?)

Putting a bigger alternator on a motor that doesn't draw more than the stock one does zip s---. A bigger alternator isn't more efficient or anything. A 60A alty will take the exact same amount of power to drive a 40A draw as a 90A capable alternator.

Thanks Charlie, I figured it'd be within reason; Still, it doesn't help to check into it

Ryan, I wasn't looking at it like that, the idea is lower cost. I can pick up a Milli alt. way cheaper than an MX-3 one around here, seeing as I've seen 3 MX3s in the JY since 2009, and Millenias are still piling up.

I believe the MX-3 alt is a 90A, and the Milli a 110? That's off the top of my head though, and wasn't my motivation anyways

Ryan wrote: Putting a bigger alternator on a motor that doesn't draw more than the stock one does zip s---.

Ryan, a couple of people on here who did the swap commented that their cars seemed to idle better with less stumbling after the swap. It was attributed to the possibility of a stronger spark.

I call BS.

Good way to check would be to test battery voltage while running before and after swap.

Ryan wrote:

Daninski wrote:

Ryan wrote: Putting a bigger alternator on a motor that doesn't draw more than the stock one does zip s---.

Ryan, a couple of people on here who did the swap commented that their cars seemed to idle better with less stumbling after the swap. It was attributed to the possibility of a stronger spark.

I call BS.

Good way to check would be to test battery voltage while running before and after swap.

So do I (yeah, I'm agreeing with Ryan. Can you believe that? ).
The alternator only produces the power the system draws from it. As far as I know, nobody has ever complained about the mx-3 alty being undersized for the job.

The main reason why the mx-3 has a weak spark is because the OEM coil is a POS. Sure, upping the input voltage would cause the coil to deliver a higher voltage too, and, since the impedance of the spark plug is (fairly) stable, also a higher current, but that would also overload the coil, causing it to fail prematurely. It's smarter, if you want a better spark, to do the HEI conversion, than to replace the alty and expect to solve everything magically.

Now, if, as MM92 stated, the purpose is to just get a cheaper, more readily available unit, then I don't see why not. If you were to nitpick the situation to the extreme, if the alty is heavier, you could argue it'd take a little more power from the engine (to turn the heavier windings), but we're talking a negligible difference here. Unless you're building an all-out, professional race car, that's definitely a non issue.
I'd also like to add that, unless our resident junkyard expert disagrees ( ), the 626-mx-6 alties should work just the same.

The 4 bangers have 60A and the 6's have 90A.
Personally I went with the 110A cause I have a small system...which I seemed to have fried something on the head unit (totally unrelated to the alty). Anyway...my friend is an electrician and has a gadget that measures how many amps are being drawn. With just the stereo, all other draws turned off, my amplifier was drawing just over 40amps.
Obviously the V6's draw more power then a 4 banger, or they would have 60A Altys too right?? So if my alty was producing its max of 90A, that leaves me with 50A, 10 less then the 4 bangers max. So with the milli alty I'm back at 70A...which is probably a safe area. My headlights used to dim everytime the bass hit, so I added 2 capacitors (only 1.5 farad total), which seemed to improve only the sound. I haven't had the system running since I swapped in the new motor/110A alty, so I can't test the dimming headlights.
Anyway...I figured I'd throw this into the mix as it hasnt been mentioned or considered.

I've held both the Altys and I can't say I remember a huge difference between the weights. But unless your designing a race car where every gram matters I wouldnt even care.

Ryan wrote:

Daninski wrote:

Ryan wrote: Putting a bigger alternator on a motor that doesn't draw more than the stock one does zip s---.

Ryan, a couple of people on here who did the swap commented that their cars seemed to idle better with less stumbling after the swap. It was attributed to the possibility of a stronger spark.

I call BS.

Good way to check would be to test battery voltage while running before and after swap.

So do I (yeah, I'm agreeing with Ryan. Can you believe that? ).
The alternator only produces the power the system draws from it. As far as I know, nobody has ever complained about the mx-3 alty being undersized for the job.

The main reason why the mx-3 has a weak spark is because the OEM coil is a POS. Sure, upping the input voltage would cause the coil to deliver a higher voltage too, and, since the impedance of the spark plug is (fairly) stable, also a higher current, but that would also overload the coil, causing it to fail prematurely. It's smarter, if you want a better spark, to do the HEI conversion, than to replace the alty and expect to solve everything magically.

Now, if, as MM92 stated, the purpose is to just get a cheaper, more readily available unit, then I don't see why not. If you were to nitpick the situation to the extreme, if the alty is heavier, you could argue it'd take a little more power from the engine (to turn the heavier windings), but we're talking a negligible difference here. Unless you're building an all-out, professional race car, that's definitely a non issue.
I'd also like to add that, unless our resident junkyard expert disagrees ( ), the 626-mx-6 alties should work just the same.[/quote]


I think your both a couple of over educated idiots with disillusions of mechanical grandeur. More available current means more available spark. This FACT has been accepted even more than the decal to HP ratio that we all know has been verified by the Tuner Nation.

It is true that the draw on the alternator at any given time is only what the accessories are asking for. But the other big consideration, I think, is the effort required to produce those amps. In theory, a larger alternator with more loops in the winding should require less effort to spin for a given draw because each revolution of the rotor induces votage and current through a larger number of loops. Although the difference between a 90A and 110A alternator is going to be pretty small.

Daninski wrote: I think your both a couple of over educated idiots with disillusions of mechanical grandeur.

You mean "delusions", don't you?
I mean, being that we're a couple of over educated idiots...

Damn it I meant disillusions. In other words, your very educated and free from illusion, clarifying any false ideas, mechanically speaking. ( When I said idiots I meant it in a nice way ).

Anyway, you can get your alt bumped up to a much higher amp output for about $150. If your running a big sound system this would probably help I'm sure.

Honestly, I just want to have the engine 100% ready to go in the car come swap day, I will already have my hands full painting and tucking the bay.

As far as the output of the amp, I'm not picky so long as it works. I'm going distributorless, so that point is as moot as the sound system one. I'm running 4 components, 2 tweeters, and a single 12 in my '92 currently, with no headlight dimming or other issues.

I'll probably go with the Milli alternator, if the weight is truly that close to the stocker. Why? Because I'm having to buy an alternator, clean it, and install it either way. For little to no added cost, I can have a "free" 20A thrown in. Few things are freebies in mechanics, and this is as close as it comes it sounds.

Thanks for the input everyone. I'll be posting a bunch more likely useless(except to myself, and maybe 1 or 2 others) questions in the near future. Good times are coming for my cars, I'm pretty thrilled to be honest.

Man, I didn't realise that going to a 110a alternator would of been such a debate, lol

Me neither, but there's some good information in here That makes it worth having asked, if you ask me. =)