09-07-2010, 10:16 AM
Join Date: Apr 2009
Vacuum after FI
Just a quick question.
After my S/C install i used a turbosmart duo port BOV with supercharger spring and a backing plate to make it a full plum back system.
However i was seeing very erratically vacuum movement, during idle it will jump from 20inha to 15, then to 5, then to +2 boost (WTH O.O)
Anyways i thought it maybe the BOV so i replaced it with the Bosch Bypass Valve the kit came in, and saw vacuum stead at around 13, i took it off and did a blow test and found it may be slightly leaking so i purchased a replacement unit.
Now my vacuum during Park and Idle is at about 15 and cruise is around 20.
Now my question is, before the S/C my vacumm during idle was around 20, cruise was around 20.
My bypass valve is pre compressor after MAF connected to Intercooler IN pipe.
Now i presume my drop of vacuum is from the restriction in the way?
Trying to get my head around it, my idle is very smooth though, and its rock steady at 900rpm.
If it isnt a restriction issue, then is it possibly a leak ?
I also ordered the petitte metal bypass valve
which will replace it.