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Need a new alternator on my TBI....reccomendations?

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PhilS10HO

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My truck is an 87 gmc 1/2 ton TBI350. My stock alt can't handle my 400 watt amp powering one ten inch sub anymore. What is the stock output? 60-70? I'm looking for a 105 amp alt. Did some searching online, but there's so many. 1,2,3 wire and such. Would like to stay declo, but I don't want to spend a fortune on this thing. I need some recomendations on what specific alt you would have me use. Links to online stores would be great. I only have a NAPA here and they're not the greatest. Thanks guys

Phil
 
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I have an 87ish TBi motor and the alternator onit was stock at 115 or so amps. This was in a suburban. Perhaps you could look around and find one for a sub instead of a truck?

I would think 105 to 115 amps would be good. Are you sure that you only have a 60/70 amp unit as it is?
 
I was asking what the stock output is. There's only one junk yard here, and the owner kinda hoards all the GM truck stuff. I think i'd rather just buy a new one and know what I have.
 
Stock output depended on what the vehicle came with. Later typically higher rated. I've seen stock truck alternators as low as 37 amps. :)
 
I just got a 100amp alt from Summit, it is also Summit brand and I paid like $90. It took about ten minutes to put it in cuz it was a fact replacement.
 
maybe u could get one of the slighty high power alternators that they are talking about, but to go with it, you could get a compasitor, to go with the amp, it just gathers up a charge from the amp while the bass isnt too loud to power the next bass hit. my friends head lights dimmed a lot before, but now hes fine. i think they're around $80 if im not mistakin:crazy:
 
lak2004 said:
I just got a 100amp alt from Summit, it is also Summit brand and I paid like $90. It took about ten minutes to put it in cuz it was a fact replacement.
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Would you happen to have a link to that? I just looked and only found 2 alts for my app. Both were pricy.
 
So what are all you tbi guys using? What's the belt style pulley called that i'm using? The name of it's right there. Dunno why it's not coming to me.

Phil
 
60 amp is standard alt for TBI but 105 amp was an option.
Have you tried going to your NAPA? They should have a 105 amp direct replacement alt for your truck. 105 amp is a stock alternator with AC and towing package. My 89 Blazer has a 105 amp alternator. They are very common. Every auto parts store carries them. I know for a fact Checker and AZ have them. I am sure napa does too.
 
PhilS10HO said:
So what are all you tbi guys using? What's the belt style pulley called that i'm using? The name of it's right there. Dunno why it's not coming to me.

Phil
Click to expand...

Are you thinking serpentine? Thats the belt style you have.
 
not sure if they are different from 87 to 89, but i am running the stock alternator on mine, with two amps running, one is a 1500w and the other is a 400w unit, the only issues i have are the lights will dim down alittle when the bass hits, only on very loud settings,,,

you sure something else is not wrong with the alternator or electrical system?

a 400 watt amp is really shouldn't have that big of a draw on your charging system.
i know if your battery won't hold it's charge like it should, this will cause some issues as well.
 
4xcrazy said:
not sure if they are different from 87 to 89, but i am running the stock alternator on mine, with two amps running, one is a 1500w and the other is a 400w unit, the only issues i have are the lights will dim down alittle when the bass hits, only on very loud settings,,,

you sure something else is not wrong with the alternator or electrical system?

a 400 watt amp is really shouldn't have that big of a draw on your charging system.
i know if your battery won't hold it's charge like it should, this will cause some issues as well.
Click to expand...

Yeah I was thinking bad or weak battery too.A 400 watt amp really isn't much of a draw.
 
Okay, so I called napa today. They said they only had 2 alts for my truck. a 90 amp for $130 and a 100 amp for $600 something :eek1: . I don't think it's my battery. I had this same amp/sub set up was in my 97 Blazer. Which has a 90amp alt. It dimmed my lights when it hit hard. My friend had a 400 pushing an 8 in his 99 blazer, and soon after install his alt died. So I don't know what to do now. Can't seem to locate an alt for my truck.

Phil
 
I called a out of my way parts sote for the 105 amp alt. $150 for a delco reman. Looks like my only option, but what do you guys think of the price. I just realised me battery is something like 4 years old. Everstart 1N.

Phil
 
I'd say your battery is just about dead, that's about the max life you get out of them around here anyways, have it checked..

Curiuos,,,what amp are you running, how old is this thing??

for a 400watt amp to dim your lights and only pushing one 10" sub, it sounds to me like a very outdated model and very inefficient.

again, with my 400watt amp pushing the mids and highs (total of 6 speakers) and the 1500watt class D mono amp pushing two 15" Kickers, mine only starts to drop the voltage and headlights at a pretty good level of noise.

I also have not installed any caps or any other devices to aide in this issue.
 
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