What is the factory vacuum pressure at idle?
I need a new a bov cause my old Greddy type s is leaking. I'm looking at the TiAL Sport QR Blow Off Valve and I need to know what spring pressure to go with. Currently the vacuum at idle on my evo 8 is .65kpa or 19.19in/hg. Is that normal? I do have a pretty bad boost leak that I'll be fixing soon and wasn't sure if that has anything to do with it? Any help I'd greatly appreciate it

 

With a completely stock engine I'm hovering around 15-16in/hg

 

If I remember correctly, my stock 8 are idling @ about 40 kpa.

 

should be around 15-20 in.hg i thought... Im 10-15 in.hg with 272 cams

 

Stock is 18in/hg - 20in/hg. Im at 10in/hg - 13in/hg with Gsc's stage 1.

 

Alright cool thanks guys!

 

Tial recommends the 6 psi spring for the QR for most Evo owners.

 

But what about this chart from Tial? http://www.tialmedia.com/documents/BOVspc.png if the factory vacuum at idle is around 18in/hg - 20in/hg wouldn't you want to run a 11psi spring?

 

That's what I thought.. Attached is Tial's reply..