Ok, I got the Hogan DP7 catted downpipe. Very slightly deeper tone, almost unnoticeable, more power in upper end, I am very happy, goes great with my Superchips Cortex Tune. Easy install, but didn't want the dreaded "code" so I decided to go with the mechanical O2 simulator I wrote about before. I installed the downpipe 10 days ago, lots of start, stop cycles, and knock wood, so far no codes. Cost of mechanical O2 simulator?? $4. One caution, the simulator, which is actually 2 HELP! brand spark plug anti-foulers, causes the O2 sensor to stick out more from the down pipe which in turn causes it to touch the floor pan. (The O2 sensor bung on the Hogan Down pipe is welded to side of the pipe). I cured that problem with a bunch of hard whacks from a large hammer and my floor jack. After moving the floor pan metal a little with the hammer, I put a large socket on the floor jack cradle to concentrate the force in a small area and put it where I wanted to raise the metal. A few pumps of the jack gently pushed up the floor pan area where the O2 sensor was touching. I pushed it up a little extra knowing the metal would spring back some when jack was lowered. I got just over 1/4" clearance all around the sensor and quit there. No problems at all until I tried to back up going up hill, I could hear the sensor slightly hitting the floor pan, thats the only circumstance though, no other time. I may make a slight adjustment for a little more clearance, but I am very happy. Photo from another site for different car, but you get the idea

 

interesting.. props for innovation

 

UPDATE! Been over 5 weeks now since I installed the Hogan catted downpipe and used the mechanical O2 simulator (two piggybacked spark plug antifouler adaptors). NO CODES!!!!! Nada, nuttin! Only problem is very minor clearance with O2 sensor and floorboard. I have to get under car and provide a tiny bit more clearance then I originally made. Only when I back up going uphill, there must be enough engine movement to cause the sensor to tap the floorboard a small amount. I will push the sheet metal up about 1/4" more, that should be plenty.

 

Wow very nice. I must have missed your first post about making this. Good inovation.

 

Thats interesting... when I did that a while back my car tossed codes. I have since then removed the pipe...I made the hole biger than a 1/2 I think...

 

Well, I don't know if I was just lucky and got no codes, but this seemed to work fine for me. I gradually bored out one of the adaptors with increasingly larger drill bits until I got to 1/2". This allows just enough clearance for the adaptor to screw on to the O2 sensor, then you screw on the 2nd unaltered adaptor piggy back. The idea I guess is to move the O2 sensor out of the main exhaust flow.

 

I also use an O2 sensor extension on my DP7S. Haven't thrown a code in over a month.
These things work!! I was clearing the damn P0420 code every couple of days before I
installed this fix.

 

I did this, my light would come on withing 10 miles of clearing it, it's been off for a few hundred miles. But I had plenty of room for mine - no banging necessary

 

Well, its now been 2 months and a couple thousand miles since I installed the Hogan Catted downpipe using the mechaincal O2 sensor and not a single code! I guess it works!!!!!!

 

Even if it trips eventaully, it's still better than clearing the code every day!

 

So, where do you get these "anti-foulers"? Any parts store or somewhere online?

 

Got mine at local Advance Auto for about $4. They are actually "HELP" brand sparkplug antifoulers. #42002 I believe.

 

Updates?

Are these things still working for y'all?

 

Yeah, still working great! Over 7 months and thousands of miles and not a single code.

 

I have a question: It seems though you guys have suceeded in doing this, but I haven't seen anyone with a "catlass" DP who has done it. Anybody??

 

There shouldn't be any difference. Isn't the bung before the cat on the catted one?

FWIW, after 5 months, mine's still working great! (knocks on wood)

 

UPDATE!!! One year latter and I am now getting a code about once every 3 weeks. Seems to be after car has been been driven, then sitting for an hour, then driven again.
I am wondering if it has to do with possible rust corrosion of the adapter/spacer/simulator. It is only carbon steel, not stainless like our exhaust pipes and after the winter here, it seems rusty. There is one on the internet that is stainless steel and they even offer one with a tiny mini cat converter in it and a 90 degree one.
http://www.bigdaddiesgarage.com/?gcl...FWV75QodumH8uQ

 

^^ awesome!!!!!

 

I just reinstalled my hogan downpipe with the stainless steel O2 spacer. I'll inform if it tosses codes again.

 

DAMN!!! Guess I didn't knock hard enough. Mine stopped working this weekend!