i got a "high flow" cat when i got my exhaust work done at mieneke. i put it in quotes because i dunno how that translates to a aftermarket cat but it was mieneke's performance cat so im assuming its higher the the stock flow one. anyway, im pretty sure when they installed the cat that the bottom was silver/chrome in color. now a few weeks later, the bottom have is dark in color, but the top is still silver. is this a sign of a engine running bad or do they change colors like that usually?

 

anyone?

 

They do change colors. Keep in mind that almost all aftermarket cats are "high flow". This only means they flow more than stock. The color change should be normal but check timing just in case. Nitrous cars with the timing retarded heat the cats up big time. Cats only cost you about 3 to 5 horse if they are in good condition.

 

i could touch the cat with my hand after about 30 minutes of the car being on driving around, is that a good indication that its running right or does it have to be running longer to see a problem?

 

No that's long enough.