Now that I've got all this fancy pants stuff in my car (stereo, e-fan, better fuel pump) my alternator just can't keep up. Without the lights on I'm getting under 13v charge.

I know I could swap to a S4 alternator, but what other options are there? I have a gilmer drive setup so I need to keep a 15mm shaft (or, buy a new pulley).

I'm wondering if the S4 alternator would be enough. Is there a way for me to check how much amperage I actually need? Obviously I'd like to have more on tap.

I remember reading on here that someone swapped a Buick (I think?) alternator in, but I can't find the thread. If possible I'd like to find a 1-wire alt that would fit, but I can't find one that has the right type of bracket or something close enough to work.

Any help? I've been searching for a couple hours now...

 

and S4 unit goes right on, i think they are 65A, the quick and dirty way to see if this is enough is to look at all the fuses, for the fan, radio, etc and add it up. the fuses should add up to be more than you need, (fuse is peak demand + a little extra) so its a ballpark, but if you have 65A of fuses, and 65A of alternator, you're in good shape.

 

The only problem with doing it that way is that I am using all the factory fuses, thereby you would think the factory alt would be enough to cover it. The only thing I've "added" so to speak is the fan, which draws 7 amps, and the MSD box which I don't believe draws much.

I suppose, that being the case, upgrading from the 50A stock alt to the 60A S4 alt *should* cover it, but I know even before I had the fan the factory alt was struggling with the lights on, which from what I read is pretty common. I'd like to have enough amps to run everything.

 

I ended up ordering this:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360676451930
I figure 130A should be anough. I'll just need to run a new wire from the alt to the battery.

 

If you want to know what the draw is get a clamp on DC Ammeter. Without the engine running clamp around either battery cable and turn on each accessory one at a time to find out what they draw.

You could have something else going wrong which shows up as low voltage. A weak battery (shorted cell) or the alternator could be going bad so the battery isn't getting charged. I assume you did check to be certain the belt isn't slipping.

 

I think so.

 

I used a buick alt which is a c130 series alt. Second best upgrade ive put on the rx7 so far. Very simple to mod to put on and takes roughly 3min to charge the battery fron dead.

 

have you done any aggressive driving where the motor stays above 7.5k rpm? Im concerned about non-mazda designed alternator blowing up at that RPM

 

So far no problem. And redlines are only guidlines for the weak of heart. I threw a double pully on it and got a matched set of belts. I did it because i read of others doing it with the same series of alternators and i just so happened to have a brand new one for a 88 buick shyhawk. They are cheap strong and easy to find.

 

pls post some pix. im mocking with a taurus 130amp alternator but it is so huge that it wont clear the distributor cap. so im looking for other options. thanks

 

Belt can't slip, it's a cogged belt (gilmer drive). It was charging fine before I went to the bigger fuel pump and switched to an electric fan, so I'm 99% sure it's just a matter of "too much stuff for too little alternator".

 

Heres a couple pics. Another cool note is my alt weighed in barely less than the factory one.

 

Have you thought of placing it where the ac goes assuming you dont have it? Id like to do that next time to help keep the weight lower and keep it cleaner.

 

That is what I did, and +1 for the GM cs130 alts.

 

So only the one wire to these GM alts? Nice. As low as $40. on Rockauto

 

thanks for the pix. This alternator is not as bulky as the taurus so less BS to install. how many amps is this alternator?

 

I used 3rd gen works good.. Just drilled out pulley...

 

Mine was 105 amps. They mostly range from 100 to 140 depending on intended vehicle. And mine is overkill as is. But should i decide to put a bigger audio system in then ill have it already.

 

i seached it says 94 and up GMs but did specify model. so models would be helpful. thx

 

I used a alt for. 1988 buick skyhawk. But. The alts were used in almost every gmc car it seems like.

 

I'm running a Nissan Frontier alternator. Droped right in place of the one that didn't work (lord only knows where the PO rednecks got that one from)

 

thanks all. just on time too. my DD 94 celica gt 2.2 ltr 70amp alternator just went out

 

is that buick alt 15mm or 17mm?im getting a gilmer setup and wondering if ill have to order the 17mm pulley after i get this.