I notice today my s/c is making a rattling noise like marbles in a can. It only makes the noise at part throttle. Idle and full throttle it has the normal whine sound to it. Also under the hood pushing the throttle lightly on its fine, but if you rev it fast you can hear the noise. It sound like something is vibrating in side. Any ideas what it could be?

Thanks

 

Mods?

 

5 lower
2.7 upper
chip
tb
ram air

 

before i put my exhaust on my truck when it would idle it ould be whining with the marbles sound. Not shure if it does it now.

 

If you have a 4# or larger lower pulley on it , then it is probably cavitation. It's like a grumbling noise from within the blower that is most audible at idle speeds. IF that is what it is, then it's a perfectly normal characteristic of the Eaton. Mine did it too when I upgraded from a 2# to 4# pulley, and it freaked me out as well. I thought the damn thing was coming apart.
The way it was explained to me (and this may not be perfectly or scientifically correct), is that with the bigger pulley, the blower is spinning faster at a given rpm(say idle), well the throttle body is only letting in so much air at idle. Meanwhile the blower (due to its now higher idle speed) is trying to suck in more air, thus creating a disturbance of the airflow inside the blower casing, causing it to cavitate, which is the grumbling noise you're hearing. Once the engine is above 2000rpm, the noise should have all but disappeared. Hope this helps...I'm no Physics major

 

It only makes the noise ? around 0 to 5 pounds of boost. not sure if my gauge is correct. At Idle in gear or park does not make noise. sound like the bearing went bad.

 

It is very possible with an upper pulley installed on the blower that a bearing could be going bad. It has happened before

 

Put a stethoscope up to snout and verify if it is a bearing......if you need a new supercharger Ill sell you my stock one...it was only on my truck for 5 months.....

 

definitly coming from s/c. But i'm not losing any boost. send me a email about how much for the s/c.

Thanks.

 

so with 4# lowers, this cavitation issue occurs with all L's or just in some L's? The reason I ask is that I am ordering a 4# pulley this week and had settled on the lower, but this sheds interesting light on the subject.

 

Well my truck just went in for the S/C snout leaking -- It made a rattling noise at idle and you could hear it pretty loudly at drive throughs because of the walls....
It didn't get louder under throttle and kinda dissappeared even at part throttle

It sounded like a rattling muffler /exhaust or something like that

 

does it sound like this:

http://spankdog.kicks-***.net/Spnky8...%208-31-03.wav

8lb lower

1lb upper

 

MAn...that sounds like sh**.....what ended up being the problem??

 

no it dont sound like that. after listening to it a couple more times it sound like its coming from the front of the s/c housing and not the snout.

Now one of my bassini muffler has a rattle to it seem like the inlet pipe is loose. anyone know how to get one replace with the life time w.