d4nk

iTrader: (2)

Im wondering if im doing something wrong, or is it these cheapo remanufactered alternators? Ive been threw about 4 alternators in the past 6 months, all of them being cheapo reman's. Should i drop some more $ on maybe a powermaster alt? Another thing i just installed a new Alpine CD Player and 2 12" Fosgate sub's. Im wondering if maybe this has anything to do with it draining power. It does fine when i keep the rpm's up, however at night when all the accessories are on ie: headlights, heater, stereo, turn signals...etc it and at low rpm the volts gauge begins to drop down into the red and everything starts dimming out. Any input would be greatly appreciated.

Thanks

Trickster

What size alternator are you using? You need something like a 140 amp alternator/

The Trickster!!!!!!!!!!!!

AllisonMTRSPRTS

Trickster is right -

I imagine with this kind of stereo equipment, you are probably running some kind of amp as well. ( even if it is internal to the CD player )

Typically, Alternators will not be able to provide the power that you need to support all electronics , plus the amps., plus subs etc.... You may have to upgrade to a higher amperage alternator.
The other thing to remember is ( by no means am I trying to insult you by telling you some of this info ), but the battery is used only to provide the cranking amps to your starter during vehicle cranking. After that, it is entirely up tot he alternator to provide the voltage to everything else.
THe reason that you see the difference at higher RPM is that the alternator voltage regulator will allow an increase to 14-16V, due to higher speed, which would be enough to supply all of your system. Anything after 16 V is condiered over voltage and the field will de-energize.

Hope this helps even if it is a little.....

Jeff
Allisonmotorsports

d4nk

iTrader: (2)

But by stepping up to 140 amp alt im going to loose output at low rpms correct? Right now its got the 108amp i beleive is what also came stock. Will I need to get an under drive pulley for it?

Trickster

By reading your post, I would say that you are already losing output at low RPM's. Also, you must remember that with all the stuff you have added to your car it is no longer stock. No, you won't lose output and you won't need an underdrive pulley. Your output will remain more constant and allow you to use more of your toys at one time.

The Trickster!!!!!!!!!!!!!!!!!!

AllisonMTRSPRTS

The other thing to remember is that even though you step up to a higher alternator, the alternator itself still starts charging as soon as the field is activated which is typically at set RPM.

So again, *tipping hat to Trickster* agree.

Jeff

Trickster

:hail: :hail: Thank You Jeff!!!!!!!!!!!!!

The Trickster!!!!!!!!!!!!!

AllisonMTRSPRTS

No prb -

d4nk

iTrader: (2)

ok im getting ready to order a new powermaster tpi 140amp alternator from summit. My question is what kind of clocking should i get? I have had problems with the clocking the last few times ive replaced it. Everytime i get an altnerator from the parts monkey its always got the post against the valve cover. Alternator mounts on the passanger side, so should i get the offset clocking or the str8?

Danno

It is normal for a Si or CS alt to do that. 86/87 was the changeover year. The reason you experience what happens is that the alt when it senses high load turns itself off for protection. Your alt does not supply the current needed to run the car, the battery does. GM addressed this problem with the CS 130D. I tried the "iceberg" 140 amp kit as well as the CS 144, both did essentially the same thing at low rpm. I converted my 89 to a "D", what a difference it made. It has a different charging curve because of an improved design. I posted an article here about the change, if you use an alt repair shop you can probably do it for less than a so called high output unit. It has been the single best change I have ever made and it's only a 105 amp unit. The 140 amp units never reach full output until close to 6000 rpm, they increase the stator but not the rotor windings-you will have LESS output at idle. GM looked at modern vehicle load and driving habits and addressed it with the "D" version to more efficiently maintain the battery at low rpm's. For a good bit of info try this http://207.158.252.111/gw/alt/edge_A...or_Theory.html