Cat bypass seems common on 348/355..

Well considering the 348 doesn't use a bypass valve, yes, yes it is easier to get around it.

 

if you mean cat replacement pipes I'm pretty sure Fabspeed make them, also Maxflo...

 

Installing a cat bypass Y-pipe from Fabspeed is fairly easy to do on a 355...5.2 engine. There aren't any sensors on the actual pipe, so there is no CEL (check engine light). Good luck.

Tim

 

Yes, the 430 is a little trickier. The major factor is that as cars get older, guys are willing to modify them more.

 

Lol...you beat me to it.

 

That would be an interesting survey: how many 348 owners are running cats (stock or hyperflow) and how many use test pipes.

Kai

 

On all the cars with two O2 sensors (5.2 on F355), the engine ECU is looking for the back O2 sensor to first read excess oxygen and then later on after a few minutes read stoichiometric oxygen. This series of readings tells the ECU that the Cat is in the system. In the mean time, the front O2 sensor is reading rich then lean then rich then lean as the ECU dances around stoichiometric fuel/air ratio and the cat come sup to temp and starts to do its majic.

So, the way around this little issue is to use an O2 simulator which has a timer circuit that gives one signal for a while and then later gives the other signal. The ECU accepts this set of readings and does not set the CEL.

Even more modern cars may have a few more tricks up their sleave.

{BTW the data is all in the WSM.}

Other than the costs of the factory Cats, the performance loss is so miniscule, that there is no real benefit to removing the cats from the system; and lots of insundry detriments.

 

+1. I doubt there is much performance gain, but you may get some added noise/volume.