lately my car has been running sluggish. iv been told the bypass valve leaks after a while. so at the moment i don't have money to buy a Detroit tuned bpv so i removed the vacuum the hooks up to the bypass valve so now it doesn't open. the car has been running great. the boost climbs up rapidly. but my question is would there be any damage in the long run?

 

From what I understand, it's hard on the supercharger. So you may prematurely wear out the supercharger if you run like that for a long period of time.

 

It's not really harder on the S/C, rember it's exactly what it says it is, the S/C works the same the difference is how much of "that" boost you're putting into the engine and not "bypassing" it.

BPV's don't really start leaking as much as the spring weakens, you can just buy a new spring but you'll have to find it in a hardware store.

Short term you'll probably notice a loss in mpg.
Long term I really don't know what it'll do, may cause the ecu to make wierd adaptations.

In a round about way what you ended up doing is the same as if you just zip tied it shut.

 

im reaching 10psi of boost at under 3k rps. where as before i sealed the bpv i would reached 10 psi at around 5k rpm. basically the car feels as if it were brand new.

 

I was under the impression that the BPV opened when you were off throttle so the supercharger wasn't over working itself by pushing the boost against the back of the closed throttle body. The air would be backing up against the lobes of the SC and cause alot more resistance to it's turning than under normal circumstances. The open BPV allows the boost the supercharger is generating to go somewhere. When working correctly, when you get back on the gas, the BPV is supposed to close again, causing all of the boost to go through the throttle body into the engine.

 

that's the problem when i would give it gas the valve wouldn't seal properly.