Found the cure to our alternator woes!!!

[big dad]

Thanks for the reply. I currently only have the bf 2.76 upper. The lower is the stock. Already gone thru a few alt and ready to get a 3.20 to see if the new alt last a little longer. Wanted to know if someone with same set up used the factory length belt or a larger one.

I have a 2.8 upper with BF idlers (90mm,and 3 100MM and aux. idler) and a stock lower, plus a 130a Ford Racing alt. with a 3.5" Metco pulley and I use a 77" Dayco belt if this helps.

 

[Turkey_Lurker03]

Have a 03 gt here...stock alt lasted 7 years about 42k miles. Had a reman alt installed lasted 3 years about 20k more miles...battery light was flickering on/off for months untill it died. Replaced with PA performance 130 alt and brand new motor craft battery and that combo lasted 6 months before leaving me stranded last week. Car is stock electronic wise, it does have steeda u/d pulleys and is a daily driver. pa has a limited warranty but not sure if I want another piece from them.... Would a SandC be a better route to take? Failure can't be from over spinning but maybe the opposite.. Under spinning? My last oem battery last 10 years the new one was almost completely drained after 6 months...tested 145/545...alt test zero...

 

[Stage 4.6]

Hummm :??: that's a different scenario. I have been running the FRPP underdrive pullies on my wifes GT, 6 months after I bought the car new off the showroom floor, have owned the car for 15 years and have never replaced the alternator I 'am on my second battery!

 

[Turkey_Lurker03]

Well shipping it back to PA, they will take it apart and find out what happened....my only diagnosis is that I was putting around drifting in traffic and keeping rpm at or below 2k which was saving me fuel but not allowing the alt to recharge the batt correctly. If the battery is low and the alt is working overtime to try and charge it back plus it has been super cold in md this winter maybe all those factors combined resulted in premature wear. I will post an update once PA determines what they are going to do.

 

[Turkey_Lurker03]

Update:
Pa picked up alt fixed voltage regulator and said it tested good. Just showed up at my door. Going to install and cross fingers for long life... Will NoT be re installing the steeda U/d pulley this time.

 

[P49Y-CY]

EDIT: I have merged this thread with another alternator thread because they both have important information on this topic.
Jimmysidecarr

Our alternators are not rated high enough to power our cars.

This is where it gets interesting. Our stock alternator is rated to 105 amps. Any given alternator is only capable of producing 80% of its rating continuously, so a 105 amp alternator can safely continuously produce 82 amps. Being an electrician I happen to have certain tools which help to prove my point here. If you place an amp meter (Amp clamp to most who know) on the outgoing wire of the alternator you can tell exactly how much amperage the car is drawing. Our cars, with the fans running and the light on pull about 70-75 amps. Turn on the A/C and radio and you are now at 90-93 amps. This is 8-11 amps above what the alternator is capable of doing. this shows the stock alternator is not even powerful enough to safely and efficiently power our cars even in stock form! I would seriously suggest EVERYONE run at least a 140 amp rated alternator.

Our alternators are 130 amps!

I thought so too...

First off, I know the stock alternators were 105-110 amps regardless of what they were rated at. After doing my own research and also speaking with quite a few alternator rebuilders they are actually NOT 130 amp units. Now the remaned ones you can buy from ford are now labeled 130 amp but I have yet to see one so I don't know for sure. Second, just because you up the amperage rating on the alternator does not mean its going to produce more heat. If you are not drawing all that amperage out of the alternator then it should stay relatively the same. Amperage rating is just a pool for the car to pull from, the alternator doesn't produce that amperage all the time. This is a common misconception.

I've purchased several Alts for from the local auto parts stores. If you get one from orilleys,autozone etc... they are all under 105 amps. I had each tested before trying to install. The only one who said theirs was 130amp was NAPA it tested 112 amps.

My stock Ford Alt tested at 131 amps. at the alt shop. My rebuilt tested 133 amps. My last Ford Replacement alt tested 132amps.

since this is the sticky thread for alternator discussion, I wanted to chime in an try to understand more regarding STOCK alternators. the above quotes from this threa seem to have conflicting claims about what amperage the stock alternators are really rated at. there are many threads about it and there are usually conflicting claims. most threads people will chime in saying our cars came with 130amp alternators, but not too many can offer actual proof other than that is their impression. but after reading all I could, including just about every alternator thread here and on modfords, I am thinking that perhaps our cars really came with lower rated alts than advertised.

all of the replacement units for mustang gt's and mach 1's are rated at 130, but not for the svt dohc vin code y, and I think that that is where some of the conflict comes from. I wouldn't be surprised if the official terminator brochures say 130 but really didn't end up in the cars at the line. in one telling thread on the discussion at modfords, a tech has alldata information that shows a maximum rating of 120amps for the unit. http://www.modularfords.com/threads...f-our-Stock-Alternators?highlight=alternators

believe it or not, my stock alternator is still going strong, still with no problems at 114k, but I have some extra money to spend right now and want to buy a replacement to have as a backup (for either car). my car has stock lower pulley and stock alternator pulley, stock lights, stereo, etc. I don't want a high amp unit (which may require wiring upgrades), and I don't want a high dollar piece either, so I am just doing my research.

 

[START 'N CHARGE]

The information I have access to,which is the rebuilding industry standard,is the 03-04 Cobras are 110 amp.The GT's,which look identical other than having a 6 groove pulley are rated at 105.
The 130 amp claim everyone throws around is the larger case 4G version which fits various models with the front mount.
They do not interchange.
That being said,I did buy a few cores a couple years ago,and one of the Cobras DID have a 130 amp sticker on it.I tried to ID the Ford number,but came up blank.My guess is it was a Ford Racing reman unit.
Picture is the 130 amp 4G

 

[Stage 4.6]

I got one of Jamies alternators don't have any mayor issues, but when I do stab the throttle or go wot my alt light flashes momentarily?

 

[Jefe]

Not a good sign, get it tested. That what mine did before the diodes failed. Hopefully its just a loose connection

 

[P49Y-CY]

The information I have access to,which is the rebuilding industry standard,is the 03-04 Cobras are 110 amp.The GT's,which look identical other than having a 6 groove pulley are rated at 105.
The 130 amp claim everyone throws around is the larger case 4G version which fits various models with the front mount.
They do not interchange.
That being said,I did buy a few cores a couple years ago,and one of the Cobras DID have a 130 amp sticker on it.I tried to ID the Ford number,but came up blank.My guess is it was a Ford Racing reman unit.
Picture is the 130 amp 4G
View attachment 24564

thanks very much for the clarification! :beer:

 

[brunocobratt]

Great info

 

[Stage 4.6]

Not a good sign, get it tested. That what mine did before the diodes failed. Hopefully its just a loose connection

I got a pm from Jamie (start n charge) yesterday, that's who I purchased mine from and he said if I sent it back he will repair it, he mentioned something about a bad lathe he had last year? Very nice guy to deal with. I just dread getting under that car to disassemble the alt.

 

[AbrahamSVT03]

Soooo ... In conclusion if i want to extend the life of my alternator and i have this setup

2.93" Upper pulley
Stock Lower Pulley and Billet idlers + The idler

The best pulley size of my Alternator should be 3.2" ?? i think i got the stock alternator installed.

Thanks !

 

[MattG04]

Im at 143K on the odometer and still factory Alt!

 

[Ryan2KRedL]

I just received my new alternator from Start-N-Charge.
Nice unit!
Installed the upgraded wiring harness also.
Car charges great!

Ryan

 

[P49Y-CY]

Im at 143K on the odometer and still factory Alt!

:rockon: nice, im at 115k

is your car pullied?

 

[Stage 4.6]

:rockon: nice, im at 115k

is your car pullied?

Iam sure the problem with these cars is when they get pullied and the alternator gets over spun.

My tuner re-did my engine ground strap, was having some issues while tuning my car, It seems to be working a lot better, no flashing battery light either.

 

[P49Y-CY]

Iam sure the problem with these cars is when they get pullied and the alternator gets over spun.

not necessarily, as long as the lower (drive) pulley is not changed from stock, the alternator spins at the same speed as stock regardless of what size upper pulley is on there.

most people attribute terminator alternator failures to heat and the placement in the engine compartment.

 

[Stage 4.6]

not necessarily, as long as the lower (drive) pulley is not changed from stock, the alternator spins at the same speed as stock regardless of what size upper pulley is on there.

most people attribute terminator alternator failures to heat and the placement in the engine compartment.

I somewhat agree with you especially the attributing failures to heat, but most people having these alt issues are not running stock lowers either, hence the change required on their alt pulley using the 3.2

 

[P49Y-CY]

I somewhat agree with you especially the attributing failures to heat, but most people having these alt issues are not running stock lowers either, hence the change required on their alt pulley using the 3.2

that's right, once you change the drive pulley (lower) or the alt pulley, all bets are off!

and even with an upper-only, I think you need to make sure to have the right size belt on there or you can toast the alternator bearings if the belt is too tight and the tensioner is at the the limit