hey just thought I would share a project that I did. I replaced my old s4 alternator with a Cosmo (20b) alternator. I am now seeing about 14.1 volts at idle, and about 13.7 with loads on at idle. I also ditched the v-belt pullies, and replaced them with cosmo serp belt pullies. Cleans it up some, and the serp belt seems to do a much better job then the older v-belts. I am seeing lower coolant temps now with this setup. Enjoy!

 

where did you get the parts?

 

I bet you were running just one belt with no air pump?


-Ted

 

I went one step further, I am seeing +14 volts even with the lights and electric fan on.
Caution to anyone considering this mod - if you want to run PS,AC, or smog it is not a simple bolt on project.

 

what makes it not bolt-on? custom bracket for like the cosmo ps pump? seems like a cool setup but i want to keep p/s. my a/c and smog is gone though.

 

How many amps is the cosmo alt anyway? I can get 14.1 volts on my s4 alt with lights off and 13.6v with lights on

 

Are any of the Cosmo pulleys suitable for our air pump?

 

stock cosmo uses v-belts for PS, AC, and smog.
I dont know anything about the smog bracket because I never tried it.
The problem with the v-belts on the cosmo set up is they dont line up at all with a FC's PS and AC bracket, so you have to modify the PS and AC bracket, since Im using a PS delete bracket I opted to go all ribbed belts and use a FD ac compressor and tensioner on my modified AC bracket, we had to weld material to the bracket, then drill and tap it so the compressor could bolt on.

All this is much easier to do with the engine out of the car.

BTW- ribbed belt would be a more accurate description of this mod as a serpentine belt is generally thought of as a single belt for all accessories.

This was my first attemp at the cosmo pulleys, you can see the main pulley has 2 ribbed pulleys and 2 v-belt pulleys.

 

probably the same as a FD, 100 amps. On a stock FC with no aftermarket radio amplifiers, no electric fan, and no stand alone, extra gauges, etc.. a stock alternator has no problem keeping up with the car.
Its when you add things that it can become a issue.

 

I got the Pullies from Japan2LA who is a forum vendor and a great guy to deal with. He sells them as a set, which includes alt,water pump, and crank pulley.

 

No I actually had the dual belts, and yes I have no air pump.

 

Cosmo Alt is 90amp
FD3s Alt is 100amp