Stock alternator size (amps)

[bsl2ck]

I have a 2003 TB LT 4x4 with the 4.2l engine. Can someone tell me the amp rating on the alternator?
Thanks

[JR4815D2]

I believe its 150 amps.. but I could be wrong....

[hatchet669]

its either 130 or 150 i think... cant remeber for sure... they ask u thins when u want to replace ur belt... if that is what ur doing... the size difference is only half an inch so just get a belt for the 150... off the top of my head i dont know the code for it tho... someone listed it before i'm sure there chime in

[bsl2ck]

Originally Posted by hatchet669

its they ask u thins when u want to replace ur belt... if that is what ur doing...

Thanks for the replys guys. I think I blinked twice and had 2 replies already.

Actually, I'm not replacing anything. I have a number of radios that need to be installed in the car and need to know what I'm working with powerwise from the alternator.

[JR4815D2]

Welcome to the site... You will have tons of info and meet cool people.... So I checked my Chilton books and it's 150 amps

[bsl2ck]

Originally Posted by JR4815D2

Welcome to the site... You will have tons of info and meet cool people.... So I checked my Chilton books and it's 150 amps

Thanks for the welcome and the information.

[ltbuick]

Check Rpo's
Kg3 145 Amp
Kg4 150 Amp

[hatchet669]

Originally Posted by ltbuick

Check Rpo's
Kg3 145 Amp
Kg4 150 Amp

damn i was right the first time on the amp... i knew it was somethign to ridiculous lol

[garym1a2]

Originally Posted by bsl2ck

Thanks for the welcome and the information.

Just to add one note, alternators are normally rated at 6000 alternator rpm, this is about 2000 to 3000 engine rpm depending on pully ratio. At low rpm that 150 amp alternator may only put out 100 amps.

[bsl2ck]

Originally Posted by garym1a2

Just to add one note, alternators are normally rated at 6000 alternator rpm, this is about 2000 to 3000 engine rpm depending on pully ratio. At low rpm that 150 amp alternator may only put out 100 amps.

So, if I am driving along at a "normal" cruise with the tach showing between 1000 - 1500 engine rpm then I should expect about 100 amps? Is that the low rpm range you mean.

The other question I would ask is, if the alternator has the capacity to put out 100 amps at cruise, how much of that is excess beyond the needs of the vehicle? I realize that will be dependent on a number of factors, but are we talking 50%, 25% or more in excess current available to drive other devices (radios in my case)?

Thanks for the information gentlemen,