what is the stock vacuum pressure in the intake manifold. need to pic a bov spring

[chrisdoesitsideways]

Im curious what the stock vacuum pressure is in the intake manifold? I will be buying a bov soon and need to know this so I can get the correct spring.

 

[Zuffen]

Why would you want/need a BOV if you're concerned about NA manifold vacuum?

If the car was turbo'd or supercharged you could/would need a BOV but then NA vacuum wouldn't matter.

 

[gloverman]

Most 1uz ive worked on with stock intake and cams have idled between 60 and 67 kpa map. Thet tend to pull around 80kpa map on decel. Ive had the odd one pull 88 on decel which was a pain as the normal map sensor I run would hit 0 volts causing the ECU to use a default value with the end result a huge backfire down the exhaust and local thinking a shotgun had been fired. Change of map sensor required.

I think the lowest readings at idle I have had is around 50kpa map. Doing a twin turbo thats due to fire up this week so will be interesting how that on goes as it has some 264 cams in it. Overlap isnt too bad though.

 

[chrisdoesitsideways]

Zuffen: tial sports website recommends buying the correct bov with the correct pressure spring to operate properly. This is based off of the idle vacuum pressure the tialsport website has a chart explaining this. If its at idle Idk if it would be different NA or Turbo and since my car is not running at the moment I can't measure my vacuum pressure.

 

[chrisdoesitsideways]

http://tialsport.com/documents/BOVspc.png

Here's the link to what im talking about