Budget M3

So...I am considering the fabspeed or supersprint bypass, but got to thinking about how folks used to get around DOT import laws in the grey market import days of the late 70's and early-mid 80's....they'd put the U.S. required catalytic converter on the euro exhaust as required by DOT, but clean the cat of all it's functional internals so that engine power remained the same. To DOT inspectors, it looked like the owner was compliant with the regs by installing a cat, but only those states that had emissions laws would detect the lack of a real catalytic converter.

Since the bypass pipes sold by Fabspeed and Supersprint are just pass throughs that elminate the cat...What if I just remove the stock secondary cat pipe, break up all the ceramic crap inside the cat, and reinstall the pipe? Voila! all the benefits of straight through cat bypass without the expense. Of course it will not look as cool as a nice shiny new pipe, but then again, how often do you get down under your car to look at the exhaust? Also, added benefit that it remains stock look to prevent dealer from denying warranty claims due to aftermarket parts...

I'm still thinking through if there is any downside to this...if I decide to go through with it, I'll post results soon...

pdxjim

The aftermarket items are lighter (I think) but like your idea. So you would cut a hole in the top (so it would not be visible from under car) and yank out the guts and weld the trap back shut?

Budget M3

That would be one way to do it...I am thinking even simpler would be to just stick a long screwdriver/small metal bar in through the existing pipe, then rattle it around a bit to break up the ceramic material and dump it out of the pipe. It will probably take several iterations before all the internals are broken up and removed.

Another method would be to just take a baseball bat to it to break up the ceramics Did that once many years ago to find out what was inside a catalytic converter--inquisitive minds wanted to know. It was lots of fun at the time, but of course made the pipe completely useless because it was so bent it would no longer fit anything!!!

tkerrmd

dont do it, the cats are expensive and heavy. the "crap" you have left may further disturb the exhaust gas lamiar flow profile and so also not be as good. so my vote FWIW is no. If you want cheap go to a muffler shop and ask them to do a cheap fab job, should only cost couple hundred dollars.
IMHO the word porsche and cheap dont usually go well together?!
good luck

Budget M3

Good advice, Tom...so I am looking for a practice subject on eBay...seen them there before for as little as $50 since no one really wants them after installing their fabspeed or supersprint pipes...Anyone want to volunteer their V6 cat as a test subject?

Yeah, I thought of that, but isn't it only ceramic material inside the cats? If I could find a way to get it ALL out of there, it should be no different than a bypass pipe, right?

Always an option as well...not sure I'd trust any local muffler shop here to fab it though. Imagine the self-satisfaction, in finding a great, simple workaround to a poor Porsche design choice. If it works, we'll call it the Purplesaurus Bypass!

tkerrmd

M3, I wish you asked about this earlier cause I would have given you my old cats!! I just left them at the shop until they "got lost" and I'm sure I wont use them again, as I own this truck.
But I think your idea of someone offering theirs up should pan out for you on this site. I have to admit all the stuff I take of my car I try to give away to rennlisters.
Oh, yeah, one other thought. If you are turning that thing back in you will have to put them back!! Or buy new ones, dont forget that and then you would be losen some dough!!

Good luck, let us know!!

Budget M3

Thanks, Tom...I'll keep you posted if anyone offers up their stock cats for "testing"

I need a V6 pipe (single pipe from header back)...any takers?

Thanks,
Mark

tkerrmd

Good luck Mark!