Q's about a larger alt.???

[Trixter 10+ year member]

I posted this in another forum but I think it belongs in this one....

I am looking for a larger alt. for my '02 Cavalier (2.2L). My Q's are... how do I know what size to get, what kind to get, and where can I get one with out being bent over?

I am running 2 Punch 200ix's at 1.33ohms and a Punch 800a4 at 4ohms, if that helps at all.

Any help is greatly appreciated.

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[MikeofTulsa Moderator]

well basicly u need to know the following info.....

how many amps your car pulls while in idle

how many amps your amplifiers pull at max current draw

and how many amps anything else you have running on your car pulls....add all them together and then get an alt that puts out a little over that or so....goo dluck

 

[Trixter 10+ year member]

Makes sense. Now I supose I need to get a meter.

 

[MikeofTulsa Moderator]

radioshack or walmart....was checking both for an amp meter, and a voltmeter.....whatever meter you get make sure it can read amperage....i think both were under 10bucks

 

[Trixter 10+ year member]

Cool!!

Thankx!!

 

[Trixter 10+ year member]

OK. I got a meter and here are my findings....

-Nothing on...~14.2v

-Radar detector

Headlights

Wipers

Heater........~13.0v

-Radar detector

Headlights

Wipers

Heater

System w/ heavy bass almost all the way up....~11.3v

Based on my findings, can you suggest an alt. size?

(The meter I got says it's only measuers up to 10amps so I figured that it wouldn't be a good idea to hook it up to the alt. in this mode.)

 

[MikeofTulsa Moderator]

look on your alt and see how many amps it puts out at idle....it should say on the actual alt

 

[Trixter 10+ year member]

It is 105a.

I can get a 160a for $210, but I don't want to get it if I can get by with something smaller for less.

 

[MikeofTulsa Moderator]

120 -140 amps should suffice....

 

[Trixter 10+ year member]

Thanx again.

You help out quite much

 

[maylar 10+ year member]

Where were you measuring, exactly.. at the battery? With these numbers:

-Nothing on...~14.2v

-Radar detector

Headlights

Wipers

Heater........~13.0v

Your stock alternator seems weak. You shouldn't dip below 13.8 v or so, even loaded up (headlights and heater motor are the big ones). A 105 should even handle the audio, or real close. I'd say 120 or so should be fine for all.

 

[Trixter 10+ year member]

Originally posted by maylar Where were you measuring, exactly.. at the battery? With these numbers:

 

Your stock alternator seems weak. You shouldn't dip below 13.8 v or so, even loaded up (headlights and heater motor are the big ones). A 105 should even handle the audio, or real close. I'd say 120 or so should be fine for all.

The hot comming off of the alt. and grounding to the frame. Whan I did it at the battery, I got pretty close to the same numbers. I figured comming off of the alt. would be a more true reading.

Any other suggestions? I am running two batteries, if that helps. Each is grounded with 4 gauge. I heard things about an isolator. I don't quite understand how it works. Would it help me in my application? I can get a 160A alt. for mralternator for $210. I figured if I got it, I would have plenty of room for later add ons.