VW MK4: Possible to replace 90A alternator w/120A?

[Mr_Accord]

So the alternator is my mom's 2004 New Beetle Cabrio w/2.0L 8v BGD died this week and I have been shopping around for a new one. The husband of one of my co-workers own and operates a starter/alternator rebuild shop and has offered to sell me a rebuilt one at cost price.

So its $145 for a 14V 90A w/1yr Warranty or $160 for a 14V 120A w/1yr Warranty.

He claims you can put the 120A in place of the 90A without any problems? For $15 more I was thinking why not? The car is question has a lot of electronic accessories so it probably wouldn't hurt to have 30 more amps.

 

[Quest]

If physical mounting and fitting works (pulley aligns properly,etc.) and all the electrical connector fits, then I'd say go for it.

Personally, I don't understand the need of anything more than 90A on a typical passenger car though...

But then again: I don't run anything other than factory stock radio, A/C, etc.

Q.

 

[RiceCake]

You can just fine. Almost always the extra amperage is there to deal with high current idle loads, usually heated seats.
Unless you've added anything that draws 20 amps to the car though, its benefit is almost nil.

The added current is just there to deal with the 20-30 amps heated seats can draw at idle, which might otherwise cause battery discharge. When driving there is plenty more current avaliable.

 

[FowVay]

The 120 amp alternator is for the diesel engine. It will replace the 90 amp alternator with no problems.

 

[Mr_Accord]

Originally Posted By: RiceCake
You can just fine. Almost always the extra amperage is there to deal with high current idle loads, usually heated seats.
Unless you've added anything that draws 20 amps to the car though, its benefit is almost nil.

The added current is just there to deal with the 20-30 amps heated seats can draw at idle, which might otherwise cause battery discharge. When driving there is plenty more current avaliable.


Well thats it. The car is fully loaded and has both heated seats and heated mirrors and electric everything. When idling and the seats are on the lights do dim until the car is accelerating.

 

[ARB1977]

Go big or go home.

 

[artificialist]

Originally Posted By: FowVay
The 120 amp alternator is for the diesel engine. It will replace the 90 amp alternator with no problems.

If you rev the gasoline engine to 6000 RPM, what happens to the alternator for the diesel that redlines to 4500 RPM?

Is the pulley diameter different?

 

[Thermo1223]

They are interchangeable just make sure you are getting the right pulley with it.

A solid pulley is not ok if came from the factory with a clutched pulley. Some did, some didn't it was mostly for TDI's though.

When mine goes(90A) I am replacing it with a 140A.