dbwade36

My pre-cats are original (129k miles on them), and I am wondering, since I have installed a hi-flow cat and flowmaster exhaust, is it worth getting new pre-cats? Are there any hi-flow/performance precats? Would that just be a waste of money?
Just seems like I have upgraded only 2/3 of the exhaust system.

larrybsp

Precats are there to speed up the warm up process to get the car into closed loop mode in cold climates. I have removed them on the two Corvettes I've had in California and I've passed smog with flying colors every time. Most smog techs don't even realize a Corvette has pre cats. They just look to see if the main cat is there. If you have an L-98 you can get a Canadian head pipe from GM without the pre cats or you can get one from Ecklers. From GM it has to be special ordered. Its not listed in the computer. The sales person has to call the order in. Been there, done that. :auto: :auto:

subman

Last weekend, I gutted my pre-cats leaving the pumpkin in place, just in case. I have been told by 2 reputable muffler shops that if your car is warmed up when you take to the smog testers, you should have no problems.

65Z01

A 2 1/2" mandrel-bent SS front Y would be the best solution; maybe you could get the pre-cat skins tack welded to the new Y.

If not, just gut them since you have a new cat.

To finish off the exhaust, you might pull the stock shortie headers, port the tube openings and cut the AIR tubes from within the header tubes.