[RyanGT]

Posted this in other thread but it has gone pretty far (and doesn't go with title so not getting views). Copy pasted... This is also at a steady idle of 1.1k rpm.

K fixed a bunch of grounds, and changed the belt. I then tested the alt, and weird things were happening!

Tested at battery terminals (the connectors) I got ranges from 13.85 to 14.2 volts. Was mostly stable but every once in awhile jumped from extremes. And once or twice it went as low as 13.7.
Turn lights on, test was mostly the same except 13.7-14.1. Just moved the ranges.
Radiator fan kicked in (with lights on) and it went to 13.3-14 range. Spiking a lot.

Was watching it for a few mins and it was stable for 40 secs, then bam goes way down then up and down then stable. Stable = .1 difference.

What is the Stock amp rating? 110? Here is where my problems are discussed. http://www.moddedmustangs.com/forums...-shutdown.html Would make sense if it is alternator (and was suggested a few times). Seems mine has issues and spikes down, which could explain the random fuel cutoff (for 5 seconds then resets and is fine). And slight misfires (goes mostly away with my boost a spark on full). Plugs are fine, cops are fine.

Opinions?

[B0B]

hey man the first thing i'd check about that miss is your spark plug gap. the boost could be blowing out the spark.

[RyanGT]

.035 with a BAS, and the miss is at partial throttle/cruise. At WOT its ok.

[zinc02GT]

Stock alternator can be 110, 120, or 130.

More than likely 110 though.

[RyanGT]

Was just curious if it was my problem how much would be an upgrade! Think those voltages are weird? Might be amp problems if it is...

[RyanGT]

Had dude test his alt and he only had .1 variance tops with his alt, at different rpms. So im going to replace it, and upgrade the wire.

What are my upgrade options? Stock is 110-130 amp im assuming? (thats whats on shucks website).

Should i get this? I know its better quality, but it is only a 130 amp. I dont run a stereo system, but i do have aftermarket fans and intercooler, bas, bap and all that kind of stuff that takes extra juice (and that hog of a fuel pump).
PA-Performance is dedicated to offering high quality products to every consumer utilizing the Internet. - PA Performance - You Only Buy Quality Once ! 1.877.471.8010
Or should i get a 200 amp. 100 dollar difference pretty much.

[sean 96 gt]

I would just pay the extra $100 for the 200amp. Never know when you might wish you had that extra 70amps...

[RyanGT]

True. There is also a 170 amp but i think its about the same price.

Does anybody know of any other sites for alternators? And think ill need the extra juice of 200 amp? Not sure how much the stock 2000 one has.

[jivepepper]

I had similar problems. That's why I mentioned it to you as being a possibility in your last thread.

I still have my new alternator sitting in the box. I've been waiting on a Metco underdrive alternator pulley because I run a larger 18% overdrive crank pulley. I was over spinning it and burnt it up. Plus once you start spinning the gt alternator to fast the brushes pull away from the shaft and start making less power. The springs are real weak in them. Even if you have the stock crank pulley it can still have some issues around 6500 rpm.

The cobra guys use them when they start changing lower pulleys. With the gt it can be a even bigger problem since the GT has a smaller alternator pulley stock.

[RyanGT]

What alt do you think i should go with jive? I think thats what was causing the weird voltages at my fuel pump that joe had no idea why.

Im sure that PA 130 amp is a lot better quality than the stock one, and will have a little extra power than a working gt alt. But i want to make sure i have a little more than just whats required. I wont ever have subs or anything like that. But i do have the twin spal fans for the H/E and all those after market crap.

[jivepepper]

If you do a search over at modular fords in the 03-04 cobra section you'll see that a lot of people have had problems with PA alternators.

[RyanGT]

Can ya link me to that forum? I need recommendations! What have those guys gone with?

[RyanGT]

Brand New Usa Made Hi-output Alternators - ModularFords.com Is that the thread you were talking about? Seems that guy has made a 160 amp out of high quality parts that can take the abuse. And stock is 105-110. So 160 would be a perfect upgrade!

[jivepepper]

That's an interesting thread.

Here's one of the threads I've beem talking about.

Another PA Alternator bites the dust - ModularFords.com

I just went with a rebuilt unit off ebay for 100 shipped

[RyanGT]

haha it turned into like the other thread with that guy making the alts. I just emailed him. Any other upgrade options? I dont want a stocker.