ok, so i put between 5-6 ounces of oil in my s/c and not i max out to like 16 psi in third and 17 psi in 4th and at about 5500 rpms it starts to drop going down all the way to 8psi at redline (7250). mods are in sig

 

and you replaced lifetime oil...why?

 

bc im running a 2.6 pulley, i get on it a lot, and other ppl complained their supercharger oil was black, im at 30,000 miles. just answer the question please. no need for bashing.

 

I wouldn't think it would make a difference. Just siphon some (20%?) out and see if it fixes the problem.

It's actually 100k miles.

 

Sounds like a boost leak. Check your gaskets/lines.

 

Doesn't seem like it would be the manifold line as it would reduce boost across the board. Is 17psi right on for the 2.6 with the vibrant head?

 

no, couple pounds low

 

hmmmm, yeah i think i will get a new s/c gasket as well. thanks guys.

 

I heard you're supposed to change supercharger oil every 30,000 miles, but I think that's only for people who really like to romp on the car. I'm at 14,500 miles and probably won't be changing mine until 40,000-50,000.

 

now that its getting cold out, i'm even seeing 17psi on my 2.8", i would go with saying that you may have belt slippage or boost leakage. Your car will drop boost for certain reasons, what IAT2 temps have you been seeing? Are you experiencing knock? Also, how old are your spark plugs? If you're getting blowout it may be close to having a rev limiter

 

if your running a smaller pulley, id consider changing the oil after 60 k miles......not before!

 

I'm gonna go with this guy. I usually get about 16 with my 2.9 - he should be up around 18-19.