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What are some other possible reasons a jrsc would not create boost, if there is NO air leaks? I bought a used one which is being rebuilt soon. Any suggestions thanks
 

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There's no roots in the casing.
 

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Discussion Starter #5
I just replaced the bypass valve, put on new hoses, and the the unit seems to be turning over just fine? No funny noises other than the belt at start up, but no boost, not even at 6k rpm
 

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You seriously have no boost? You sure? You have a boost gauge set up?

Did you route the belt around teh JRSC pulley?

Assuming everythign else is correct I guess the roots clearance is highly out of spec (dont see how this could happen).
 

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Squeel on start could indicate slippage under acceleration, get a smaller belt(or re-route, do search) and report back.

Either the bypass is screwed or the belt is slipping like crazy.

If you had a vacuum leak you would notice it otherwise, so I doubt it's that.

- Drew
 

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on my svt i had very very low to no boost unless i slammed it to the floor, RPM had nothing to do with building the boost (ie runnning at 6k for a bit doesnt make boost but getting there hard should correct guys?) I started pushing my guage when I changed pullies and now can hear a whine that overpowers the engine and exhaust noise.

oh and make sure you have at least the stock crank, undersize crank will kill it also
 

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yes cruising at any speed, the bypass valve is open, so there is vacuum from the engine sucking air in as if you didn't have a blower at all... once you floor it, vacuum is over compensated by pressure, closing the bypass valve allowing the air to go only one way....into the engine, pressure.
 

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You don't have to floor it for the bypass valve disengage, I could build boost at part throttle just fine.

Now, with the 3.0 pulley, that was very hard to do


- Drew
 
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