Ok, scroll up.
Snowtoy already posted picture of EGR with modular.
The backpressure helps the modulator............
It closes off the 'T' that has a vacuum escape at the bottom.
I don't understand how more exhaust back pressure is going to affect the mixture to go richer? I ran a DT header and free-flow exhaust on my 22R with EGR valve and the spark plugs always looked great.
How does one determine the PSI of back pressure to effectively change the function of the EGR valve?
At what RPMs does the EGR actually work?
Gnarls.