Hyperflow cats: before and after

Just wrapped up a nice 2 hour wrench turning session with 3forty8 (Thanks Eric!) on my F355. DMV says it's time to get my car smog checked again so lamentably the hollowed out Hyperflow cats needed to be replaced. Here you see a pic of the left side HF cats ... mmm, shiny!

Pretty straightforward project.

Jack up the car, take rear wheels off...undertrays can stay on.

- Get the 4 bolts holding each cat in place loose
- Disconnect Cat Temp Sensor
- Disconnect O2 sensor (2 if you have 1996 or later) and this can be tricky to get the O2 removal tool into place.
- Jimmy it like hell back and forth to get it to release from the sleeve - try not to let the exhaust donut hit you in the kisser.
- Once loose, it will just slide down and out the back of the car with ease.
- Put the new part in place. Jimmy it like hell to get it to mate up properly.
- Put everything back together (nuts and bolts, O2 sensor(s), Cat Temp probe) - 2 notes, please use copper anti-seize on the threads and a pair of pretty standard vise-grips will work fine to crank the O2 sensor back into place.

An extra pair of hands is pretty useful for a couple of the bolts but I imagine you could do it solo without too much agony.

Anybody want to buy a pair of hollowed-out Hyperflow cats? You could use them as test-pipes or get them re-cored and save a bundle. Make me an offer I can't refuse.

Rick
Image Unavailable, Please Login