Manifold Vacuum on 16V with ITB's...

[jondee86]

On my 16V smallport I have Silvertop ITB's mounted on a custom
fabricated tube manifold. Vacuum is sampled from all four inlet tubes
by way of small bore hoses (same size as OEM MAP sensor hoses).

At idle I am only getting 30 kPa of vacuum (70 kPa absolute pressure).

This seems a bit low, so has anyone got ITB idle vacuum readings to
compare ?? I'm going to check the reading from the brake booster
connection, as that comes from a larger set of manifold tappings. Just
to make sure the small hoses, to and from the map sensor vacuum
tank, are not causing a restriction.

Cheers... jondee86