gutted cat vs straight test pipe observation

Bought a set of test pipes to replace the cats in my 355 as I was getting some hot temps I thought in my rear engine compartment and wanted to prevent potential fire hazards.

After considerable work removing the cats I found they were already gutted unfortunately, I replaced the gutted cats since i bought the test pipes anyway thinking they might possibly make a difference.

Interesting results, using Peters's infared temp gauge the gutted cats had a temp of 335'-340'F, the test pipes are around 230'F thats almost 100' F cooler, my assumption is the metal in these and airflow are designed to hold heat, the gasses must swirl around in them vs going straight out the back, the test pipes are also significantly louder then the gutted cats as well the car seems to have much better low end response, I would expect this with a fuctioning normal Ferrari cat but not a gutted one.

 

Interesting point, I'll bet the gutted cats were actually taking away power from stock which is why the power gain is so noticeable.