OttawaLS1

If installing Hooker LT's and Hooker Y-pipe, can the stock cats and O2 sensors be kept? Or, will the cats have to be removed and O2 simms used also? Car is a 1999 T/A A4.

Thanks!

jrp

iTrader: (16)

stock cats: why bother, they'll justs choke off the system anyway and you'll need to weld them in the ORY, not worth the time and/or effort.

you'll need to remove the rear o2 sensors and run sims and run extensions for the front o2 sensors.

read the sticky at the top of the page

OttawaLS1

Thanks for the info My computer at work is too slow and searching around for the info was very painful

So with no cats, and a supercharger, any chance on passing visual and sniffer emission testing?? Would high flow cats solve that problem?

LS1LT1

iTrader: (16)

Probably not...a good set of high flow cats could help though, you don't lose all that much power through them and they could make the difference between passing and not passing if you're right on the edge.
They'll help with any visual inspections as well.

OttawaLS1

So would it be wise to save up for coated headers, or would the cheapie ones last a while if never winter driven?

Z-Rated

Get the coated, its way worth it IMHO