CEL with slp catted x and longtubes

[fr96ss]

Anybody get a p0420 code from an slp catted x and long tubes on an 03 gt code say catalyst efficiency below threshold(bank 1) passenger side. I emailed slp about the problem.

 

[propellerhead]

I remember reading something about a need for a longer delay in your tune. The cats are farther away from the block with your long tubes, and that's throwing the sensor readings off.

 

[BooWFO]

Yeah what he said. Sometimes with the LT the exhaust gases cool off throwing off the readings.

 

[mity2]

My BBX did that after install. But after little driving, it went away