Are you saying that you installed shorty headers, new cats, left factory y-pipe and downstream cats... and have heavier fumes?

No. I installed DT shorty headers, new hfc, stock y-pipe and Gibson y-pipe back exhaust. The Gibson has no cats, its a straight through exhaust with one resonator.

DT---->HFC---->Factory Y-Pipe---->Gibson Cat Back---->

The Gibson was installed prior to the headers so I don't know how much of a difference the factory exhaust will make.

So naturally without the factory exhaust after the y-pipe the fumes will be stronger than stock with headers. Hope this helps.

Was you ever able to get the CEL to go away?

I'd also like to know if there is a solution to the CEL.
I put an order in (group buy) with Jason B and was told the spacers would prevent error codes being thrown.

If that isn't true, or if there is a certain installation procedure to follow, can someone verify please?

Say Hello to my Lil Friend

Howdy. I know this post is from a while ago, but do you still do this? Thanks

Unfortunately I do believe that @duffdog has stopped making and selling the "minicats", I have mentioned him in this post so maybe he will reply and elaborate, but he may not since he doesn't visit the forum that often anymore.

After months of trial and error I finally got the check engine light, the ABS light and the track control lights to go off on my 2003 v8. Im posting this so hopefully you can learn from my mistakes. I bought the car with cracked exhaust manifolds and all the lights on the dash were lit up like a Christmas tree..

I got a set of Doug Thorrley headers from Burtmann-Industries. They took forever to finally get here due to the pandemic. Anyways I finally got them on and all I can say is buy a stud extractor socket from the auto parts store before you tear into it. I’m running a K&N intake, longtube headers, y-pipe and Gibson exhaust. NO CATS!

Now I was told to put spacers on all of the o2 sensors, front and rear. DON’T DO THIS! put the front ones in like normal and then put 2 spacers in on the rear. I got 2 strait ones from burtmann and then ordered 2 - 90` ones from Walmart of all places. You want size 18x1.5

I ended up buying all new Denso o2 sensors from Rockauto.com for a lot cheaper than the stealership and I also had to get a Toyota brand gas cap cuz the lady I got the car from bought one of those cheap ones from autozone. Also the previous owner tried to rewire one of the o2 sensors and did a crappy job. They just twisted the wire together and wrapped it in electrical tape. So after all that trouble shooting there was only one thing left to do..

I did a zero point calibration and started it up! Haven’t had a check engine code or traction control light since.

Anyways this literally took me an entire year to figure out working on it in my free time, but I hope this can help someone.

Glad you got the CEL cleared.

Just for reference so that people are not confused.

You are correct, do not put spacers on the forward most sensors that are installed in the headers themselves. They are Air/Fuel Ratio sensors, not o2 sensors, and have to be installed like the factory configuration with NO spacers. They need to be in the normal exhaust flow to translate to the ECU if the fuel trims are working properly in real time.

The rear sensors are installed behind your Catalytic converters, and are your actual o2 sensors. They let the ECU determine if the Catalytic converter is up to temperature, and burning off the excess hydrocarbons that don't get burnt in the combustion chamber. Hence the need for spacers or simulators, when running a vehicle with no CATS.

Exactly, I used a 90 degree o2 simulators on the rear.