How often should I check and/or put oil in the SC?

There is no interval for changing/adding that I am aware of. However the oil is $6.50 a bottle (small) at my local dealer. If you take an old spray bottle sprayer, pull the plug on the SC and pump the old oil out, then put in new to the bottom of the plug threads you will be all set for a while.

I'd suggest changing it about every 1-2 years depending on mileage.

PS.. It smells bad.

REAL BAD!!!!:
just changed mine for the first time..

Whiner...lol

All the NEBF folks smelled it. I think it'* a smell I'm not looking to be around....but it'* not unbearable.

it smells bad?? I didn't think so.

Interval is actually about every 10,000 miles.

No 'official' interval for service is listed. I change mine yearly in both cars.

Once a year will defintaly keep it good, i changed mine before BFEST, checked it here not long ago, still VERY clean, almost clear.
When i changed it, it was black and stunk like hell.

Me GM service manual says "the supercharger oil should be CHECKED every 50,000KM
(30,000miles)or every 36 months"

Right, being that it'* under a quart in a splash type setup only to mildly lube the gears on the front of the rotors, there'* no real dependency for it to be changed regularly.

If it'* never been changed, it'* a pretty cheap and easy insurance if you ask my opinon.