Alternator replacement

JKBEAUMONT1

MEMBER
2008 CHEVROLET SILVERADO
V8
4WD
AUTOMATIC
24,000 MILES

I am looking at replacing the stock alternator (145 Amp Max I believe) with a 200 Amp HO alternator from DB Electrical. This is for my present aftermarket car audio setup (1000 Amps Max RMS - I get a little headlight dimming at full tilt) and to plan for future upgrades.

I have done my homework and am certain that their alternator is the proper one as my current OEM alternator is a 2 pin DR44G series. The new 200 Amp HO alternator will come with an overdrive pulley that is smaller in diameter than my current pulley so the proper current will be flowing at idle.

Anyways, removing the stock alternator and replacing it with the HO alternator looks pretty straightforward. My only concern is setting the proper belt tension once the HO alternator is in place. Do I need any special tools to get the proper tension on the belt so it's not slipping? Secrets? Tips?

Thanks guys!

5 Replies

JACOBANDNICKOLAS

MECHANIC
108,133 POSTS

If the pulley is only a small amount smaller, the tensionier should make up for it. However, if it doesn't, you will need to measure the belt length around all the pulleys following the belt diagram under the hood. Keep in mind, the tensionier will be in furthest position so compensate for that. You will need it to be about an inch shorter.

Just FYI, we always recommend direct fit replacement parts. Are you sure the new alt will not have an adverse affect on the electrical system? Is the regulator (part of the alt) designed to compensate for the additional output?

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Thursday, May 13th, 2021 AT 6:52 PM

JKBEAUMONT1

MEMBER
13 POSTS

First, where is the tensioner and how do I go about loosening it so I can loosen the belt and remove the old alternator? Also, and more important, how do I re-tighten the tensioner and ensure I have the proper tension on the belt? So far it sounds like it is trial and error which sounds a bit scary.

As for the 250 Amp HO alternator I am looking at, well, your guys (experts) on this fourm suggested that with a 1,000W RMS audio system, I would need an alternator with a 224 Amp capacity. So 250 Amps is the closest I could find. I am in the process of adding a 2nd Kinetik HC 2000 battery to my existing Kinetik HC 2000 battery and will be curious to see how the OEM 145 Amp alternator handles the additional battery. However, I have been told it may contribute to premature failure of the alternator.

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Thursday, May 13th, 2021 AT 6:52 PM

JACOBANDNICKOLAS

MECHANIC
108,133 POSTS

The belt tensionier is spring operated automatic tensionier. Here is a pictire of one:

The pulley is on a pivot. You remove the tension by turning the pulley up or down based on what direction will eliminate tension from the belt.

As far as the OEM alt, yes the added draw will cause it to have a much shorter life.

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Thursday, May 13th, 2021 AT 6:52 PM

JKBEAUMONT1

MEMBER
13 POSTS

Regarding the tensioner, I read all over the place that there is a bolt you need to loosen to loosen the belt and the same bolt is used to tighten the belt. Which bolt is that? And again, is it just trial and error to get the belt properly tensioned?

As for the alternator, how does adding another battery kill the alternator? On the one had you are saying that an HO alternator will kill the electrical and on the other hand you are saying that another battery will kill the OEM alternator. Which is it?

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Thursday, May 13th, 2021 AT 6:52 PM

JACOBANDNICKOLAS

MECHANIC
108,133 POSTS

The tensionier is automatic and there is no bolt to loosten. It adjust itself via spring tension. As far as the alt. The OEM will need to work double time to charge additional batteries and to maintain the added load. The new on will be able to handle it. I suggested that it be properly regulated for your vehicle.