90 Amp Alternator upgrade?

[montanaman]

Hey ... my '91 XJ 4.0 has a denso 75 amp alternator in it. I can get a 90 amp for just about the same price. Will it work or will it create problems?

Thanks!

[CanMan]

It will be fine. Might as well check out 5-90's wires as well. Alot of positive comments about his setup.

http://www.geocities.com/JeepI6Power/electric.html

http://www.geocities.com/JeepI6Power/price.html

[5-90]

Originally Posted by montanaman

Hey ... my '91 XJ 4.0 has a denso 75 amp alternator in it. I can get a 90 amp for just about the same price. Will it work or will it create problems?

Thanks!

Uprating your alternator should pose no particular problem. The voltage regulator (in your case, inside the PCM) keeps the voltage constant by regulating the supply current from the alternator. Even your 75A ND unit probably only touches is maximum power output occasionally - my 185A Delco spends most of its time down around 50A or so (but it lets me gives people a jump-start that much faster, for instance.)

However, there is some circuit protection in or under your PCM that is selected for your 75A ND - if you do get more than that out of your alternator, you'll probably end up blowing the alternator fuses or the fusible link. What would cause that? Excessive demand upon your charging system - like giving a flat battery a jump-start, or starting your engine after running your stereo (Key ON, Engine OFF) for a couple of hours. Not that that would be a huge problem - you just need to replace the fuses or fusible link.

However, I also offer an ANL fuse block kit (some measurements required - sorry) that will allow you to upgrade the fuse protection to match your alternator, and (especially if you have a fusible link!) to save a few bucks on replacements, and be able to replace your fuse in about a minute. If you're interested, please email me for details.

And, if you really want a boost, give Rod at San Jose Generator a call. (http://www.geocities.com/JeepI6Power/sjg.html). I managed to talk him into doing mail-order a little while ago, and more than a few people here are as happy with his work as I have been for the last ten years or so. How about a 130A unit? Couple that with upgraded mains (mine, or someone else's) and an ANL fuse in the alternator output line, and you're good to go for nearly anything!

[xjtrailrider]

I upgraded all 4 of my XJ's to 120a with no problems.

[pudge]

Originally Posted by xjtrailrider

I upgraded all 4 of my XJ's to 120a with no problems.

are the 120's found as an OE option on anything? or would that be a aftermarket purchase? I'm looking to do and alternator upgrade.

[pudge]

oh, on a 90 4.0l auto

[Jess]

I think 100 amps was the highest offered stock on an XJ. Some of the ZJ's came stock with a 140 amp, which I think can be used in the XJ.
You could take your old alternator to a shop and have it built up as high as you want. I just had one built to 160 amps for about $100.

[5-90]

Originally Posted by pudge

oh, on a 90 4.0l auto

Delcos were used on earlier XJ's (1990 and older w/gas engine,) and they can be uprated as well. Since you've got a 1990, you've likely got a Delco CS-130, but you can confirm that with the "ID Guide" pictures on my site.

I think Delcos were the first I'd heard of to get uprated - starting with the old Delco SI series (with the two-pole regulator connector) a couple of whiles ago.

A Delco CS-130 can be readily had to up 140A - anything past that would be a "special job" that you'd have to pay for (like going to Mean Green.)

[xjtrailrider]

My 90' came stock with a 110a, The front bearing went out a while back so I had it upgraded to the 120a by a local shop during the rebuild. I liked the job they did so well that they have upgraded all of the others.

[5-90]

Originally Posted by xjtrailrider

My 90' came stock with a 110a, The front bearing went out a while back so I had it upgraded to the 120a by a local shop during the rebuild. I liked the job they did so well that they have upgraded all of the others.

Stock? I doubt that - the CS-130 used in RENIX XJ was originally rated for ~85A max output. It was probably replaced by the PO (I could see AMC uprating from the factory, but not ChryCo. Your 1990 was built by ChryCo.)

Still, it wouldn't cause any trouble to uprate - although if you do run full output, you're likely to pop your fusible link, since it was only rated to pass max OEM alternator current (which is, as I'd said, ~80-85A.)

Solution? Replace with ANL fuse - which you can then swap for whatever rating you desire. That's what I did - I'm running my 180A Delcos through ANL200 fuses, and haven't had any trouble.

[sjkimmel99]

sorry to bring back a slightly stale thread but just wanted to add a data point for future searchers.

The build sheet for my 96 SE says it came with a 117 amp alternator. The generator label says it is a Denso 5685. Other searches for this part number on google confirm it is a 117 amp alternator.

[5-90]

Originally Posted by sjkimmel99

sorry to bring back a slightly stale thread but just wanted to add a data point for future searchers.

The build sheet for my 96 SE says it came with a 117 amp alternator. The generator label says it is a Denso 5685. Other searches for this part number on google confirm it is a 117 amp alternator.

That sounds about right. I know the ratings went up as the model year advanced (mainly due to more electronics) - but I don't recall the break points. Later XJs did come with 120A, and they stepped down as you go back...

[smilesyota]

I just replaced my 90amp in a 93 auto ho with one from a 98 dodge durango with a 318 ( 137amp) had to grind the inside of the bracket alittle but this has been in my jeep for about 3k miles now, no problems. Cost about 50$ at the junk yard.

[pabloconrad]

This is a posting from another thread: a 200a alternator, but I think a few of uus can make it work.

http://cgi.ebay.com/ebaymotors/JEEP-CHEROKEE-COMANCHE-WAGONEER-HIGH-OUTPUT-ALTERNATOR_W0QQitemZ130093761412QQcategoryZ33573QQ ssPageNameZWDVWQQrdZ1QQcmdZViewItem

[Jess]

I just got a stock Renix alt built up to 160a, and it was only about $100. I haven't tried it yet since the engine is still in pieces and the dinning room table (wife is not happy about it either).