Alternator: Does size matter?

[smegun]

want to replace my looks to be stock alternator there are 90 amp 130 amp and 200 amp units 5 1/8 and 5 5/8 types

cost is marginal does it matter on the 94 what alternator I can use

 

[Roadrunner777]

I went from 90 to 130 amp, and also went with a reduced diameter pulley. I am in snow country and I discovered that the 90 amp barely supports winter driving, i.e. headlights, blower, wipers, rear defroster, etc... I found that, if I were at a stoplight with all this stuff running, the alternator simply could not keep up with the load.

I'm not sure that would apply to Florida, although I know you get the occasional storm. I do know if you are going to run a serious aftermarket sound-system, then you do need to upgrade the alternator.

 

[Jason94sport]

I went with a 130amp. It's actually from a F150. I had to swap the pulley with my stock pulley but it runs just fine. I noticed off the bat the 130amp was physically bigger then the 90.
As long as it's a 3g & has the correct voltage regular connections it should fit. Like I said you may have to swap your pulley.

 

[Maniak]

I went from 90 to 130 amp, and also went with a reduced diameter pulley. But, I am in snow country and I discovered that the 90 amp barely supports winter driving, i.e. headlights, blower, wipers, rear defroster, etc... I found that, if I were at a stoplight with all this stuff running, the alternator simply could not keep up with the load.

I'm not sure that would apply to Florida, although I know you get the occasional storm. I do know if you are going to run a serious aftermarket sound-system, then you do need to upgrade the alternator.

Where did you get the smaller pulley from and what did you look up/ask for?

I'd like to use a smaller pulley on my 130 amp alternator. Running the A/C fan on high, headlights, off-road lights, rock lights and aux (trans) fan is a little much at idle.. IIRC, my alternator is off a 1996 Limited.. but I'd have to do some digging to make sure..

~Mark

 

[Roadrunner777]

Summit Racing has them. I think it is this one...

http://www.summitracing.com/parts/asp-520004/overview/make/ford Includes some cool Summit Racing stickers...

Or this one from EBay for $5 less and $6 shipping. There are dimensions at the bottom of the listing:

http://www.ebay.com/itm/Ford-6-groo...ssories&hash=item27cbf21e53&vxp=mtr#vi-ilComp

I guess it's pretty universal. My alternator came from an F-350.

You will, of course need a shorter belt. If you end up going this route, let me know and I'll get the part number off of mine.

 

[smegun]

thanks guys so I can use a air ratchet and take off the original pully and I should be fine right ?

 

[Roadrunner777]

I would first compare and see if you need to swap pulleys. My donor alternator from an F-350 was a dead match for my alternator.

If you have access to an air impact wrench, then wrap the pulley in a rag and clamp the pulley in a vice, and do the do. BTW it's not a taper fit, it will slide right off.

If you don't have air impact, then take it to a shop. A pulley change should be less than $20.

Or, you could buy the reduced diameter pulley as above, and then you can just vice the heck out of the donor pulley and use a breaker bar.

Whatever the case, and I can tell you know this already... just for future readers... Be sure to disconnect the battery before you do an alternator swap. Seriously, if you do not, you should expect some underhood fireworks. This is a great opportunity to replace belt pulleys too.

 

[smegun]

theres 200 amps for an extra 20$ he ha

seems it should be ok

relays work to hard and such a higher amped alternator should be quicker
less relay workings

anybody know about 87a vs. 87 on the relays my ac relay is the only oddball using 87a instead of 87

 

[Roadrunner777]

The thing is... bigger may not be better. The stock wiring supports the 130 amp alternator. If you go bigger, you may have to replace the cable from the alternator to the battery.



But, again, if you really want to work on this wiring, get the diagrams.

 

[Jason94sport]

Also not all 200amp alternators are really 200amp. Most of the time that is the max amperage at X RPM. The idle amperage is what matters. You could have a 250amp alternator that only puts out 90amps at idle.

 

[jd4242]

Who makes the 200amp? If its db electric DO NOT BUY IT!!! I bought a 220 from them, starters it came in a 90 amp case and blew up like three years later.I took it to a local shop to have it rebuilt and the guy took one look at it and said NO WAY IS IT 220.he then pulled it apart and confirmed it was just a 90 amp alt.he also said it would be very tight and hard to even make a 220amos in a 90 amp case.

The 130 amp has a larger case and more room to make more amps.I bought a 130 at the junk yard and had him make it a 230ish amp, can't remember off top of my head but he put it on a machine and showed me the amp draw.I run dual batteries and a BUNCH of crap and it works perfect. I also run a smaller pulley.so if its not a 130case don't belive its putting out more than 150amps

Here is a pic of the two different cases.130 case is on the left.notice how much larger it is but bolts right in.notice the holes on the front.how you can tell right off the bat

 

[smegun]

nice anything to get your buck

... ok ill take you advice on the 130 any other fitting problems compared 5 1/8 to 5 5/8


other

how do you get around the two batteries tied to the solenoid

ive seen a modern cap pack instead of battery.... charge fast and capture juice fast and deliver juice fast there small in size too industry is making hybrids from what I here might take strain off the system of calls made to the alternator relays and wiring some people are only using a cap pak daily commuters the atkins delema

.....in parallel and in series to make 12.4 volts kinda makes sense gives em 3 to 4 days of charge i want to make one for emergencies right now that i can use for emergencies cap battery cap he ha

 

[jd4242]

nice anything to get your buck

... ok ill take you advice on the 130 any other fitting problems compared 5 1/8 to 5 5/8


other

how do you get around the two batteries tied to the solenoid

ive seen a modern cap pack instead of battery.... charge fast and capture juice fast and deliver juice fast there small in size too industry is making hybrids from what I here might take strain off the system of calls made to the alternator relays and wiring some people are only using a cap pak daily commuters the atkins delema

.....in parallel and in series to make 12.4 volts kinda makes sense gives em 3 to 4 days of charge i want to make one for emergencies right now that i can use for emergencies cap battery cap he ha

I don't know what you are talking about when it comes to the 5 1/8 or 5 5/8....

I run dual post deep cycle batteries. One post connects like normal and one runs to the rear battery. I have no problem charging either, takes alittle longer to fully charge both when I fully drain them but being deep cycle they still hold a charge to start the truck.

I would just throw a 130 in and call it a day unless your drawing tons of amps.

My thread just to show what I'm running.also running three amps for my stereo, over 4, 000 watts.but have a cap inline for them
http://www.explorerforum.com/forums/showthread.php?t=333598