Mission: Eliminate the Stink

My mission, whether I choose to accept it or not, is to try and reduce the rich exhaust smell. I realized that while I love driving this car, I don't really love the smell from the tailpipe. That rich exhaust smell wafts up from the back and just gets into everything. After a drive, my clothes and hair smell like exhaust. I think this is part of the reason TK doesn't really like to ride in the 308.

So, how to get rid of the smell? I figured I can start with the catalytic converters. Rather, my lack of cats. That's not entirely true -- my cats are still there but they just don't work. Somewhere in the past, they've been hollowed out rendering them useless as a catalyst device. Putting in some cats that actually work should help.

The OEM cats are NLA so I have two remaining choices. There's a company called Hyperflow that makes high performance direct replacements. However, these are REALLY expensive ($800 EACH!) The other option is to get some universal cats that are about the same size as the originals (less than $100 each). I can't justify spending almost $2000 on cats so needless to say, I chose door #2.

Here's my starting point. I got two Magnaflow 94103 stainless steel universal cats. These are pretty close to the same size as the originals, although they are oval vs the original offset egg-shape.



I started by building a jig out of wood and bolting the original cat to it. This would ensure proper alignment of the flanges on the new cat.



My plan was to cut off the original flanges and weld them on to the Magnaflow. I also had to cut out and weld in the threaded nipple where the "slow down" thermocouple attaches.



Next came the chop saw to cut off the original flanges.



Lots of grinding was needed to remove the excess metal around the thermocouple nipple.



I had marked on the jig the location of the nipple on the OEM cat. I transferred my marks to the new cat and drilled a 1/2" hole to accept the nipple.



Ok, looking good so far. Here's the Magnaflow bolted up in the jig with the old flanges. This model has an 1 3/4" inlet and outlet, which happens to be exactly the right diameter. The old flanges slide perfectly inside the Magnaflow pipe. All I had to do was to trim off about 1/2" off the length.



After some welding, here is the final product. I have one day left to get the other cat cut and welded and the exhaust put back together in time for E@RTC on Saturday. Hopefully, I'll make it!