EGR exhaust backpressure

[miklos]

I have a 1990 240sx. I was told by a smog tech that my exhaust doesn't have enough backpressure to open the EGR at idle.

I have a large cat--not high flow and a coffee can muffler with a silencer in the tip.

The tech said I would lower NOX by getting the EGR to work with more backpressure.

Should I add a resonator to increase the pressure?

[sil80 monster]

put high octane gas in and make sure your CAT is HOT....worked for me

[miklos]

I added a resonator and the car has more power. Plus it is quieter. Going for a NOX test next.

[Rabboni]

Your egr shouldn't work at idle. the only way to properly test back pressure is to put the engine under load during the pressure test (i.e. on the dyno) and then see if i creates enough pressure. Easier way to test your egr it to apply vacuum to the egr valves signal port while the engine is at idle and listen for the engine speed to drop, or start sputtering, or die.

[S14DB]

we just covered this. search....

http://zilvia.net/f/tech-talk/167571-egr-affected-exhaust-size.html