Higher Amp Alternator

pointless for the most part. There are not the electronics like newer cars have. Unless you are adding a massive stereo or a coffee maker there isn't much advantage.

 

Yes, there's a couple threads here on parts lists and such.

 

Fixed

 

According to the manual, my 75 GT4 has a 66Ah battery and a 55 Amp alternator. Just for comparison, my BMW 850i (with a crapload more electronics and chassis electrics) has two 65Ah batteries and a 140 Amp alternator. The Japanese version of that car even had the option of a second alternator.

If you are going to upgrade the alternator you might want to consider upgrading the battery capacity as well.

 

Just park it on a hill

 

The combination WP + alt belt set-up of the carb 2-valve 308 is/was well-designed for its original intended use -- when they added the extra electrical load of the CIS fuel pump and went to bigger alternators things got iffy (and they did the SB and changed the V-belt system design). Anyway, just wanted to say you might need to address the belt design if you go to a much larger alternator.

 

I assume the typical upgrade was with the OEM alternator. When I had my 55 amp unit rebuilt I had them bump it up to the max output they could . It came back at 85 amps which worked for my 77

 

Get a smaller pully, spins faster.

 

Not a good thing. Too high an RPM is just damaging to the alternator. On competition applications lower ratio pulley sets are used to avoid just that.

 

I have wondered about doing this. I'm not particularly into stereo equipment in general but I have installed a 500 watt 4 channel amp in mine. I have high end component speakers as well.

I drive on the highway a lot between Birmingham and Atlanta with the top out. The only way to hear the sound system over the wind noise and Tubi is to have a big amp with high RMS speakers.

Am I slowly killing my alternator with the added stress? Would rebuilding it to a higher output be the thing to do?

It's been in about 15 years now.

 

Even if you are, it is probably less expensive to rebuild your alt or your battery than one of your speakers. It made it this far!

 

I have had more than one alt die on me over the years in various cars circa late 70's early 80's.

The one in my QV is probably original. I haven't touched it since I bought the car in 1997 and it is beginning to make me nervous. It has to be at about the end of it's lifespan based on my experience with the others over the years

If I pull it out and rebuild it as a preventive measure, I was thinking of upping the output, if that were possible. I had the Scirocco up from 55 to 85, figured I could do the same with this.

 

I would think you are doing more damage to your hearing then to your alternator.

 

I know... It doesn't even really sound that loud - until you slow down.

 

Kinda hard to tell by the outside

 

your alternator is an easy rebuild for these cars. If you need help I can get you parts. I think I currently have enough to do three more minor overhauls (bearings diode brush pack)
http://www.ferrarichat.com/forum/308-328/480660-bosch-alternator-diagnosing-repair.html

 

Do it. It won't hurt anything and if it costs the same why not. I ran one just to be on the safe side as I had an electromotive ignition and that thing sucked some juice at high rpm. I couldn't believe the original alternator lasted 37 years though. Unreal. I had every record from day one on that car along with a good talking history with the original mechanics, one of which was Patrick Otis who confirmed the alternator and starter were original.

 

They wont though. The rating of the alternator will not make any difference to anything unless you are drawing more current than the current it can supply. It will charge the battery faster after the drain of starting the car (incidentally placing more load on the drive) but thats it.

If you were theoretically drawing more than 55 amps from the battery other than the starter motor feed, the wiring harness would melt.

Devices such as window motors and lamps would only be faster/brighter if supplied with a higher voltage but alternators have voltage regulators so there is no difference in the voltage output of any alternator unless its being overloaded and this is a virtual impossibility on these cars. The only exception might be if you were to fit an enormous stereo and wire it directly to the battery but even then a stereo which outputs 500W of power (which would burst your eardrums) only would draw 40 amps of current.

A higher rated alternator would stress the belt and pulley more, for the 30 seconds or so when full output is being achieved, ie just after having started the car. So more belt wear, bearing failures. A clear disadvantage.