k guys.. i am a stereo installer at a local car stereo shop here in yakima and, as you might imagine.. i plan on amplifying everyspeaker and having a HUGE amp to do the subs. its my hobby and what pretty much all my expendable money goes towards... SO...

what size alternator is stock on the 1990 cherokees with the 4.0 liter I6 engine?
also, what options do i have for beefing it up? im looking for no less than 120amps.. but a 140 woudl really be best.

Lets see...It is 15 years old now? Hard to believe it still has the original on there.. You are most likely sporting a 60 or maybe 80 amp alt. You already know what it is you NEED so it don't matter much what came on it.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

I beilive it is a 65 amp. You can get a mean green alternator that will pump out a solid 200+. the diodes arn't they highest quality, but since you will be running it through a step up transfomer and proabbly a huge cap it won't matter.

ok so yeah keeping the stock alternator is out of the question.. i did notice the voltage gauge moving slightly lower wheni turn the blower (heater fan) on high.. thought that was kind of a bad sign.

so where can i get a larger one? what are my options?
200amps is a LOT of current.. that would be pretty crazy to have. but would it stand up to the current demands of a stereo playing with lots of amps? it wouldnt be one draw of 60-70 extra amps.. it would be a draw of between 30 and 80 depending on the music being listened to.
would need something thats voltage regulator can handle the peaks.
but yes i will be putting in two deep cycle batteries (one for power, one to use as a cap). AND a 1 farad cap since i already have one laying around.

and what is this step up transformer? i alwasy had chevys before and it was as simple as just switchign out the alternator and power wire going to the battery since the voltage regulator was built inside. is a jeep going to need more parts to upgrade teh charging system?

Dude I did not go to school for this stuff but some others here did... I am sure they will correct me if I am incorrect..
The way I understand the charging system is that you will need a GOOD battery. The battery takes care of the ups/downs varying amps and the alt follows as needed. This keeps the alt from jumping around from that 30 to 80 amps back and forth. I think the alt allows the battery to discharge slightly and creeps it's amp output up to compensate for the AVERAGE of the amp draw on the system..
You can google alternators (police ambulance, high output) and find the GREEN and others at prices you might like.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

thanks a lot guys. i foudn a different jeep website too and did an alternator search on there and looks like the mean green is around $350... NO probleM makes me happy cuase the reason i got rid of my toyota truck was because i could not upgrade the alternator.

the alternator actually charges your battery. but you are right.. the battery acts as a stiffening capacitor (but with WAY more capacity (storage space) than any 1 farad cap you buy in a stereo shop. the battery "stiffens" the voltage and helps even out the voltage peaks and drops. i plan on running a yellow top under the hood with a high output alternator and maybe even a yellow top in the back of the jeep right next to my three amps.

i am going to run the V12 series Alpine amps. two M605s, one to power each of the subs i am getting (600wRMS@2ohms each). and then the M345 (i think it is) 4 channel to power the front speakers. all that power and i will most definately need a high output alternator.

I bought a Meen Green from Quadtratec and it only lasted for 3 months. I called their number on the instruction sheet only to find it was no good. I finally got a good one on line and called but had to leave a message. No one called me back so several days later I call ... and called ...daily for 2 weeks. Finally got someone who apologized and said someone would call me back.
No one called me back so several days later I call ... and called ...daily for 2 weeks. Finally got someone who apologized and said someone would call me back.
No...that is not a cut and paste error....it happend.
I finally got a live person again and told them someone will not call me back, I wanted to talk to someone right then..preferably managment. I finally got an RMA number and address to ship it to and an assurance Mean Green will take care of the problem. Boxed it up and sent it off...that was months ago.
Now I am back to leaving messages and attempting to get a real person again. Good thing I still had the stock one on hand.
My advise...go to a local alternator shop and have them make one for your application. If something goes wrong, you can take it back and get it taken care of...unlike me. <img src="/forums/images/graemlins/frown.gif" alt="" />

Howdy Phoenix Folks did not do business like that 70 years ago. That was back when Sam Colt made the rules of business.. I think it was these guys that got the pistol packing laws passed. There are some people that need a good old country lesson taught to them..

Your post alone will keep me from EVER purchasing a Green!

I have been in the same business for 40 years and the ONE THING we do is answer the phone. No matter how much we do not wish to take the call...we take it anyway.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

Mean Green update:
Finally got a hold of the same manager today. He looked up my file but had no answers. After finding my application was an '89 YJ, he said "I imagine you are ready to go play huh?
<img src="/forums/images/graemlins/zombie.gif" alt="" /> I grit my teeth and calmly explained that I had only ran his $300 alternator for a few months and have been without it for a few months.

Once again he apologized and promised to take care of me ASAP but I'll believe it when the package arrives.

As far as I am concerned, when they got the old one in their hands, I should have been sent one off the shelf that day.

Maybe this was a fluke, but I'll never buy from Mean Green again. <img src="/forums/images/graemlins/scared.gif" alt="" />

Manley, that's really unfortunate that you had a problem with the mean green altenator. I bought a mean green altenator for my YJ just a couple of years ago, It has been working well for me; no problems with it. I believe I purchased it through Quadratrac.
It's not likely BigJim would be purchasing any large output altenator in the near future, but BJ's response just goes to show that one negative comment on this board about any product can have a serious effect on an after-market manufacturer's sales.
The other point I want to make, is that there are equal or better altenators in the marketplace, mean green is not the only HD altenator manufacturer. From what I've been told, they are usually less expensive, too. I haven't had any reason to explore this matter. It's funny how all the alternatives flood in after you purchase any part for your Jeep! <img src="/forums/images/graemlins/smile.gif" alt="" />