Here are some pics of the Dual Alternator pulleys Install on a S5 engine:

You can also see pics in this thread:

https://www.rx7club.com/forum/showth...threadid=89277

 

This may sound stupid but what is the advantage of that set-up? To run your electronics more efficiently?

 

and also get rid of the smog pump...

 

Nope, not a stupid wuestion at all. The purpose is to maximize cooling system performancewhen:
You have removed your cats and your 6 ports, hence eliminating the need for the air pump.

When you remove the air pump, the engine will only have 1 belt driving the water pump. This one belt will slip decreasing cooling system effienciency. Here is a photo of the stock set-up, now compare it to the pic above.

 

Forgot the pic.

 

i got a little belt and put it on just the main pulley and the water pump. it gets about 3x more contact than any other setup

 

How hard was it to change the pulley? I really need to do this to my GXL sometime soon.

 

Need to? Man, the effects are minimal...but you'll need an impact gun to take off the free spinning nut off of the alternator. I think a 14mm wrench and/or14mm socket w/ ratchet and a block off plate...

 

I dont understand how you couldve done that. The water pump allows no adjustment for belt tension.

 

Haha, I have NO other belts on my car, I think it'd be a good idea

 

Do a search for "yahoo belt" or "yoohoo belt" Both of these terms are in the same thread. I have one of these belts on my car and it worked very well. Belt costs like 3-4 dollars. Sure its not as cool or as good as a dual-belt pulley but it does the job.

 

you have to use a screwdriver ot something to get it on
it takes a little muscle, but it works good.