cat temps

[crankor]

After replacing my cats, my temps stayed around 600f. (With a leaky y pipe) It took a while to get the new y pipe on cause I had to have an exhaust shop cut,rotate, and reweld on one of tge flanges. So now that its on, my temps go up to 900-1090 from casual driving for 20 min. Is this normal? I'm not really sure what's considered "heavy load" would that be hard acceleration or low rpm driving?

[AZhitman]

Typical cat temps can reach 1,600°F or so, so you're well within the normal range.

Leaking cats won't get hot enough to catalyze (which you learned).

A P0420 code would indicate a problem with converter efficiency.