Adding premix to the fuel will slightly raise the vacuum and build more compression. Reason being is the extra lubrication from having the oil sprayed into the combustion chamber will lube the housing/side plate walls more effectively. The extra lubrication allows for all the internal seals to "SEAL" better in the combustion chamber, which in turn creates more suction.

 

15 inHg @ 900rpm
PFC reads about 430 mmHg, reads about 40-50mmHG when the car is off.
Mazda Reman w/~20k miles. Read about 16inHg a year ago, but I have about 8k plus 500+ track miles since then. Owned the car a year.

BTW there is already about a 5-6 page thread on this if you want to search for it.

 

What idle rpm and vacuum are people getting with half bridge ports??? Aggressive ports that is!!

 

This is based on what data I could pull together from the forum.

This should be able to give you a good idea of where your engine compares to the masses..

 

20 in/hg at 1100ish, sometimes settles down to 750ish, with same vacuum.

63k on rebuilt.

 

440mmhg/17.3inhg @ 850rpm on the stock motor with 89k on it...