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Alternator sizing???
- Thread starter cybrfire
- Start date
Jason4x4
1/2 ton status
not sure about the si, dn, but I believe the numbers at the beginning signify the clocking of the alternator. Not 100% though.
There are other options, depending on motor and year. The Pontiac Transsport alternator is relatively inexpensive for the performance, and is a drop in on 350's, IME; there are high-output GM ones that are perfect matches -- some Caddys had these, for instance.
Or you can get a one-wire high-zoot one and be done with it
-- A
Or you can get a one-wire high-zoot one and be done with it
-- A
dremu said:There are other options, depending on motor and year. The Pontiac Transsport alternator is relatively inexpensive for the performance, and is a drop in on 350's, IME; there are high-output GM ones that are perfect matches -- some Caddys had these, for instance.
Or you can get a one-wire high-zoot one and be done with it
-- A
I think that's what I'm gona do. I got my eye on a 140 amp, 12SI chromie. Original application would have been a K30 454. I'll be making my own bracketry anyway so shouldn't much matter.
Thanks!
Those numbers (12SI, etc...) don't specify what amperage the alternator is capable of. I think factory 12SI's are around 60-70 amps but I have seen high-zoot ones rated at over 100.
One thing to keep in mind that a lot of these high-zoot rebuilt alternators with high amp ratings will only offer these ratings at really high rpm...at idle and lower speeds that a lot of 4x4's will see they don't put out any more than stock.
My suggestion would be a CS144 "large case" that was found on several vehicles stock (could be one of the ones referred to in another post). You can easily get 140 amps out of these, and the nice thing is they put out a lot of juice at low rpms also. It's kinda' like the difference between a 300 h.p. 454 and a 300 h.p. 4-banger in an import. Granted the h.p. rating is the same, but there is a big difference on where that power is.
One thing to keep in mind that a lot of these high-zoot rebuilt alternators with high amp ratings will only offer these ratings at really high rpm...at idle and lower speeds that a lot of 4x4's will see they don't put out any more than stock.
My suggestion would be a CS144 "large case" that was found on several vehicles stock (could be one of the ones referred to in another post). You can easily get 140 amps out of these, and the nice thing is they put out a lot of juice at low rpms also. It's kinda' like the difference between a 300 h.p. 454 and a 300 h.p. 4-banger in an import. Granted the h.p. rating is the same, but there is a big difference on where that power is.
