120a Alt upgrade

Electrical mods for the hi-end modder. Such as wiring harness hacks, swaps, etc...

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Calimus
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120a Alt upgrade

Post by Calimus » Fri Jan 27, 2006 5:04 pm

Ok, so recently I ran acrossed some chatter on my rocco list about a certain model year passat altenator (120a) that will drop in on the existing A1 atl bracket. All thats needed is to change the pully and the electrical connections to the alt.

I know that since I added H4's, to cristines cabby, that there is a strain on the system when they are on, even though I relayed them. Not to mention the radio/amp combo I have in there prollie isn't helping either. So I'm thinking maybe this could be the answer.

However, I'm slightly concerned about the ability of the rest of the electrical system to handle the load. I'll be honest, I can wire all kinds of crap, but I don't really know all the much about how the atl functions with the car. Does it only seep out whats needed or does it toss the same ammount out all the time?

I'm trying to find these things about before I pick one up and fry the car. :D
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Post by Briano1234 » Fri Jan 27, 2006 7:00 pm

Well I just was on the tex, and some one there stated that he used a 120Amp GM alt. He was going to do a write up about it.


Most alts, are just a motor that runs in reverse, the gauge of wire, and the number of turns and packs determine the current that the thing puts out.

The Regulator is really the heart of the thing, cause it takes the ac and filters and changes it from ac to dc, then using a series of diodes rectifies it.

You can run your H4's off the battery direct by using a couple of relays, and they work ok.

THE MOST that your alt can put out is 60amp/hour. So stepping it up is probably a good thing.

Also getting a larger battery may help too, there is a 1250CCA from interstate that is a almost direct fit. Save for having to bend the radiator shroud a wee bit.
Briano

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Post by SoCal_Cabby » Fri Jan 27, 2006 10:00 pm

i wonder if it will drop into my jetta also.........
my stereo could use the extra oomph

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Post by Calimus » Sat Jan 28, 2006 1:50 am

Brian, you're right on target with my current setup. My H4's (in both the cabby and my rocco) are relayed off the battery. An in my rocco at least is a overkill style battery. I can't recall the CCA's just now, but I know it's way more then the car requires. I'll have to look into the alt thing though.
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Re: 120a Alt upgrade

Post by CalAltaDubber » Sun Jan 29, 2006 9:45 pm

Calimus wrote: However, I'm slightly concerned about the ability of the rest of the electrical system to handle the load. I'll be honest, I can wire all kinds of crap, but I don't really know all the much about how the atl functions with the car. Does it only seep out whats needed or does it toss the same ammount out all the time?

:D
William, all electrical components take only the ammount of current that they require to operate.

The altinator both operates the system and charges the battery.

Even though your Alt. can output 120 A the car radio still only uses 10 or 15 A. (it varries between radios). The big thing is to make sure that the wire that is in use for the most current drawing devices is heavy enough. By operating them streight from the battery (controlled by relays) you should have no problem.
Phil

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Post by Briano1234 » Mon Jan 30, 2006 3:42 pm

While that is true, about doleing out. if you have a 600watt amp running your sub woofer as some do, then according to ohms law P power in amps equals I amps times E voltage.

so 600 divided by 12vdv = 50amps.

Ricers wonder why they blow out batteries and alternators because of thier big honking Stereos or Subs....

The voltage meter in the Cabby is on a multi drop circuit. If you wire it to a more direct route, or a less loaded circuit you see the true measure of your system.

With the H4's on, and the A/c on and a good Stereo system, you will probably be taxing the hell out of the Alternator, to have ti keep the 12 volts up, and the current flowing. ie: you will burn out the regulator. This original alternator was marginal at best for the loads, but it does the job. With the way that they have the Stereos with the AMPS you need proper cabeling, and proper amperage avail.

That is why the Starter and the Alternator have big honking wires.....
and why good Stereo Shops use big honking wire to run systems.

The H4's only pull at most 15 amp each, with a 120W stereo pulls 120divided by 12 is 10amp so right there you have a 40amp draw. Leaving 20amp reserve that will be cut in half by the tail lights, and god forbid running the a/c

One additional thought is that you can use a clamp on inductive Ammeter and start your car and turn everything on Brights a/c full fan, and crank the stereo up and have some one cycle the windows to tell you how much you are drawing. You might also be able to go to a "Advance Auto Parts and have them test it on the car, as they can tell you how much you are drawing and if your alternator is able to keep up.

:)


So Upgrading to the Audi or 120 vw one is not a bad idea.
Briano

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Post by CalAltaDubber » Tue Jan 31, 2006 9:08 am

Good points Brian, I believe that Cabriolets (all A1 and A2 cars for that matter) with A/C already have a 90A Altinator installed as opposed to the 65A that is in cars like mine (A/C for me is the top down at 60 MPH).

Just the same, the upgrade is not a bad idea.
Phil

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Post by Briano1234 » Tue Jan 31, 2006 9:14 am

CalAltaDubber wrote:Good points Brian, I believe that Cabriolets (all A1 and A2 cars for that matter) with A/C already have a 90A Altinator installed as opposed to the 65A that is in cars like mine (A/C for me is the top down at 60 MPH).

Just the same, the upgrade is not a bad idea.
I had mine tested and it's a 60 amp.
Briano

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Post by Calimus » Tue Jan 31, 2006 10:12 am

All very good info. I'll be looking much deeper into the 120a alt very soon. As soon as I find something out, I'll be sharing with all of ya.

An yes, I have amps in the cars, but certainly not pushing them hard. While my rocco does have a 600w @ 2ohms, I have it only putting out about 200w. I'm sure it still draw a good bit though.

So, it looks like some rewiring will happen when I tear my rocco down as well as hopefully a nice fat alt.

Thanks for all the info guy's, it's much appreciated.
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CalAltaDubber
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Post by CalAltaDubber » Tue Jan 31, 2006 3:07 pm

Briano1234 wrote:
I had mine tested and it's a 60 amp.
Mine is the one that came with the car and is rated at 65A.

I will have to do some checking.

Let you know what I find out. I have been told that the 90A is a streight bolt in. The extra current is needed for the A/C.
Phil

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Post by foursixthree » Mon Mar 20, 2006 9:58 am

Any one ever get any info or links on this? I have to change out my Alt and would like to go this rout now if i can Thanks

Mondo

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Post by CalAltaDubber » Mon Mar 20, 2006 2:11 pm

foursixthree wrote:Any one ever get any info or links on this? I have to change out my Alt and would like to go this rout now if i can Thanks

Mondo
Best I can still find from my sources is still standard is 65A and 90A for AC cars (in MK I terms of course).

There are several different altinators that came equipped. but the ratings are correct as far as I can still find.
Phil

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Re: 120a Alt upgrade

Post by Spykce » Mon May 04, 2009 9:51 am

While I'm not sure i'll get a response, has anyone done an alternator upgrade? I was going to go get a 90 amp one from an A/C car but if there is a 120 amp option I would prefer that. Any info or links are appreciated.

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Re: 120a Alt upgrade

Post by CalAltaDubber » Mon May 04, 2009 2:49 pm

Spykce wrote:While I'm not sure i'll get a response, has anyone done an alternator upgrade? I was going to go get a 90 amp one from an A/C car but if there is a 120 amp option I would prefer that. Any info or links are appreciated.
I don't know if anbody has tried that with a 120 Amp Alt. But if the thing fits it will work. The question becomes, is the cost and labour to do the job worth it?

As for using a 90 Amp Alt. it is probably easier to do since they are almost (depending on the electrical connection) a "plug and play" fit.

Of the folks that I know that have gone with the 90 Amp unit, there have been no complaints. It really comes down to what kind of load you are going to put the electrical system under.

If you intend to have a Killer Sound System, you will need to do some research to determine what you will need to do.

Without a few more specifics, it becomes hard to advise you which type of Alternator to go for.
Phil

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'88 Cabriolet, "Posh Bunny"
'04 Golf
'12 Golf Wagon TDI
'69 Manx type Dune Buggy (New Toy)

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Re: 120a Alt upgrade

Post by Spykce » Mon May 04, 2009 8:42 pm

I installed a 800 watt amp to power the 6.5" component polk speakers I installed in the front doors, as well as an 8 inch sub. This is obviously causing an issue so I have not yet played it very loud, especially at night. I am going to relay the headlights sometime this week but I'm thinking I will go with a 90 amp also. The car has manual steering and no A/C so it has few strains on it.

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