993 cat bypass
Posted: Mon Jun 22, 2009 12:28 pmJed Clampett Metal Fab solution-
Looking for a cat bypass yeilded the $1000+ disco solutions on ebay or the $500+ Fabspeed solution that won't let me jack the car by the engine anymore. So I bought two 2" u-bend pipes with a 4.5" radius ($9 each) at an ORW type place and stopped by a muffler shop and had them bend me two 45 degrees in the middle of a 24 inch 2" tubing ($7 each). I stopped at a tool shop and bought an $11 dollar flair tool. I cut the collector off both ends of the cat and discarded the 23lb cat itself. The 2" u-bends slipped right inside the metric tubing, adjusted/rotated it to the right position and welded it. Flaired the other end to accomodate fitting the 45 degree pieces inside and welded them too. Bolted it in place and voila! I wired the post cat O2 sensor in clear air; no CEL. It is a bit louder, but not dramatically so. While I was at it, I cut the chrome part off the tail pipe ends (2-3 pounds each): I had some heat issues near there and cleared the path for more airspace for heated air to exit. Can't say I noticed the added sound, nor the increase in power that the aftermarket brags about. But, I did remove 29 lbs from the extreme rear of the car, always a good thing in a 993!
$43 dollars, not including the welding wire and gas (pennies), and my time (less than pennies).
Looking for a cat bypass yeilded the $1000+ disco solutions on ebay or the $500+ Fabspeed solution that won't let me jack the car by the engine anymore. So I bought two 2" u-bend pipes with a 4.5" radius ($9 each) at an ORW type place and stopped by a muffler shop and had them bend me two 45 degrees in the middle of a 24 inch 2" tubing ($7 each). I stopped at a tool shop and bought an $11 dollar flair tool. I cut the collector off both ends of the cat and discarded the 23lb cat itself. The 2" u-bends slipped right inside the metric tubing, adjusted/rotated it to the right position and welded it. Flaired the other end to accomodate fitting the 45 degree pieces inside and welded them too. Bolted it in place and voila! I wired the post cat O2 sensor in clear air; no CEL. It is a bit louder, but not dramatically so. While I was at it, I cut the chrome part off the tail pipe ends (2-3 pounds each): I had some heat issues near there and cleared the path for more airspace for heated air to exit. Can't say I noticed the added sound, nor the increase in power that the aftermarket brags about. But, I did remove 29 lbs from the extreme rear of the car, always a good thing in a 993!
$43 dollars, not including the welding wire and gas (pennies), and my time (less than pennies).
American Ingenuity at its best. 
