bypass valve problem on Steggy 4

[wtsn8ke]

Just got my steggy 4 installed and it's not making the power it should. Only picked up 33 rwhp with it and Accufab TB/plenum and 60's. It seems that the bypass valve is not opening. Could this be the reason i'm not picking up more power?

 

[99S_V_T]

Im no expert on posi blowers but why would the bypass valve not opening, which releases boost presure, cause u to not make power? I mean it releases air right? U sure its not stuck open? Wat boost are u seeing?

 

[01yellercobra]

Yeah. If the bypass wasn't opening you wouldn't be losing any power. But your part throttle would suck. Check to make sure it's closing all the way.

 

[wtsn8ke]

Seeing 15.3 pounds so that's about right for the setup. Swapping the bypass from my stock SC tomorrow so we'll see if that's the problem. Figure if it's not opening then it's possible it's not making a good seal too.

 

[99S_V_T]

my bet would be the seal is bad, but u are still making boost so who knows....

 

[CDR Stang]

The state of rest for the valve is closed - same as in boost mode. With vaccum it's open. There should be a small amount of preload in it's state of rest, so it closes completely. I think preload is .125". You can check that before you swap the valve.

 

[wtsn8ke]

There is one other thing concerning me. One of the two bolts that holds the bypass mechanism on the outside of the blower broke off. The shop seems to think that it should be fine with just the one bolt holding it on. Do you thing that's OK or could that cause some play in the valve???

 

[CDR Stang]

If it's holding the valve closed with tension (preload) at rest state, it should ok. But you may have found the problem with only one mounting screw holding it on - not allowing it to keep the preload.

Did you just put the 60s on it? And your tune checked out? What did you have for timing?

 

[wtsn8ke]

timing was 19 on 91 octane tune and yes, 60's are new.