Low Boost

shoalcracker

Registered User
Currently topping out at 7lbs boost.

Blower has what I think is the rolling marbles sound.

This I believe is the coupler from what i've read. Laser is showing about a 10 degree (hotter) difference in that area of the charger as well.

Does this typically coincide with lower boost?
 
my sc also has a tad of the rolling marbles sound but boost gauge reads 10 psi at 3k-4k rpms and for some reason will reach 14 around 5500. Im sure the 14 is probably wrong, stock boost gauges on the 2 previous boosted cars ive owned have always been a bit off. Do you have an after market gauge installed?
 
Car is all stock right now. I have only put on 800 miles since purchased.

Base dyno in November was 200 & 300 then it was put away for winter.

I didn't watch boost while on dyno but have to presume I had 12lbs to get to 200 rwhp.

Started twice while in storage and showed no adverse signs from sitting.
 
I would say that, regardless of the bearings' condition, if you spin the blower a certain speed, you should get a certain amount of boost. So it shouldn't be dropping off. However, it could then lead to a couple of conditions that might drop your boost.

The first is belt slip. If the bearings make the blower hard to turn, maybe the belt is just slipping over the pulley and the blower is spinning slower than usual. You should see a lot of belt dust around the blower snout if this is the case.

The second is rotor damage. This would only apply if you had problems in the front or rear rotor bearings, not in the snout. If the bearings were really, badly gone, the rotors could rub and wear the clearances too large. But that seems unlikely.

If neither of those is the problem, then maybe you have a leak or a problem with the gauge.

(And watch those fingers, hair, and tools around moving belts!)
 
Take the belt of and turn the SC by hand. You will know right away if there is an exceptional load on it that would cause the belt to slip as steve suggested.

Have you checked for any leaks at the top hat, IC tubes or the intercooler?
 
Stevie,

You ever try my inlet? Let me know whats up bro. Hope all is well with you and Christina.
 
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