A more indepth view of what the Split-Port is for those who wondered.
A split port intake is when air is channeled to different parts of the plenum, and ultimately the cylinder head. spit port induction is not that common, but it was exactly what made the power delivery for this 2.5 as impressive as it was for its time. Each inlet valve has it’s very own dedicated intake track which starts at the plenum which we will refer to as the UIM (See photo from previous post) The long runners are slightly smaller on the inside than the short runners are. At low engine speed the air traveling through these ports have a longer distance to travel, which results in a higher air velocity. The higher velocity air helps better atomize the fuel being sprayed into it’s path, and the end result is a nice even distribution in the cylinder to be compressed.
To insure that the long runners are used under low load and low engine speed a secondary set of throttle bodies are installed in the lower half of the plenum which we will now refer to as the LIM. Once sufficient load is placed on the engine or sufficient RPMs have been reached, the secondary set of throttle plates will be opened to allow for air to be pulled in from the shorter length and larger diameter short runners. At this point the ECU increases the duty cycle of the fuel injectors to compensate for the extra air flowing into the head from both inlet valves now,
One of the fun things about this DOHC engine, is that it is not a Direct acting cam, instead this engine has the cams perched well above the valves, and a set of hydraulic lifters have a roller follower rocker connecting the cams to the valves. This results in a zero lash engine which under normal operating usage will never need to have a valve adjustment, or bucket replacement/adjustment.
Over the course of the next few months I will be setting up for port matching all 24 intake ports, and all 6 exhaust ports, as well as removing cast flashing.