Anyone Have Headers Installed Without Cats?
 

I am trying to get headers on my ride but, as the title implies, having trouble with Catalytic converters. Isn't that always the case?

So, if you have headers WITHOUT CATS…please tell us HOW you solved the problem of throwing CELs. I have heard you can a "mini cat" that plugs in 'out of the stream' of exhaust flow. Otherwise it is ECU flashing time. Are there other alternative? If so, what?

Really wanted headers for Christmas but must solve the "emissions thing" first. While i want to put car on the track, I still want it semi-street legal. I live in the country so passing emissions is easier than CA. I have already done a Cat delete.

Please tell me what you have done and elaborate.

Thanks in advance.

Having no CEL doesn't mean that you have solved the "emissions thing".
I do a lot of ECU reprogramming for race cars where we eliminate the cats and get no CEL due to that, but once you remove the cats the car IS NOT street legal anymore.

Happy Boxstering,
Pedro

I used 2 spark plug anti-fowlers on each O2 sensor. Drill one out so that the tip of the sensor fits through it, and then screw it into the other anti-fowler, then put it on the car. I've done over 3k miles without a check engine light since installing this setup. The best thing though would be to get your ecu reflashed, then you get proper tuning for the headers, but that's $$$$.

Reroute route
 

I wanted to avoid a remap so I rerouted the secondary censors to after the secondary cats that are further downstream. I had to lengthen the censor wires by over two feet, and carefully route them away from exhaust heat. I hope keeping the secondary cats will get me through smog test in due time, guess it depends on how strict they are where you live, as removing the primary cats will newer pass visual inspection.
The downstream censors are not vital for the engine management like the upstream ones, but are supposed to trigger CEL if the cats fail. I bought some ½ in stainless steel tubing that is threaded on the inside in a shop that sells hydraulic fittings and welded it to the exhaust, just after the secondary cats to fit the downstream censors.
If I fail the smog test when time comes, I guess I will try new midi tubes with 200 cell sports cat. At least I have no CEL´s so far.

I've both experimented and written extensively on the topic of exhaust mods for the 986 boxster. Simply installing a set of headers will not only fail to improve performance, it will render the vehicle non OBDII compliant as well. In short, there is no inexpensive way to improve the 986 exhaust system, or get around the issue of a CEL.

I tried this too with Dansk 2ndary sport cats. Car ran great but always had CEL for poor O2 heating.