Flowbench testing
 

Just streetported a gen-3 engine today. The stock rear housing flowed 141cfm@28. After the porting was done ( i raised the closening of the port 7mm and the duration 2mm) it flowed 164cfm a gain of 16%. With the lower intake manifold attached on stock port it only flows 128cfm. Then i ported the manifolds obtrosions and 1mm in diameter and hooked it on to the ported housing, result 156cfm a decrease in flow by 5% ok but no gain in airflow. With my theoretical hp calculator the outer housings is good for 266hp w/out manifold and 252hp with. These numbers are for N/A add 15 psi of boost 100% increase? This week i am gonna port the exhausts gor a gain for at least 20%. Finally the engine drops into the RX-7 and shall be dynoed on a Sun Chassie dyno with paralell twins and a large intercooler. Pretty excited by the results.

what type of a bench did you use?

I use a flow quick digital measuring meter. It automatically shows the correct flownumbers in 10" or 28" even when the pressure drops with more opening of the intake port. I am flowtesting within 20 degrees each time i move the rotor so the flow will be measured at 14 points. Have used Flow Quick since 1997 and have gain a lot of airflow with both street and bridgeport side housings.