I need some advice on 1998 EK. I have Japspeed 4-2-1 manifold and unknown make decat which I want to put on my car.

The manifold has a hole on the side for the O2 sensor. My standard manifold also has it. So can I basically just swap the O2 sensor over or will I have to buy a new one?

I don't have a catalytic converter on the car. I think it's within the manifold. It's a D-Series 1.5 engine. Not sure engine code.

Can I still put decat on without the O2 sensor? Will that affect anything or is it bad for the car?

Another question is, I always thought there are springs in the bolts to connect manifold and cat but mine doesn't have springs. The previous owner has put a custom after market b pipe and used long stainless steel M8 bolts without springs. Is this ok or not?

Why did Honda used springs in bolts for some of their cars anyway?

Thanks

 

The primary o2 sensor is just fine. For the secondary, run a proper sized defouler and you will be just fine with no issues or codes. And no springs on these cars

 

Are you in the US? If so you may want to check with your local emissions testing as in states with a state emissions inspection you will automatically fail with no catalytic converter in place. List your year make and model because the 1.5 didn't come in the 96-00 Civics in the US.

 

Check out the username and tell me you don't know who this is already. RonJ, confirm OP posting from Washington state?

 

i saw the name and began wondering if the thread would get moved to GDD

 

With the 6th gen models I'm pretty sure (but not 100%) the EX and SI models were the only ones with a cat-back catalytic converter. Cat-back being the catalytic converter being further (back) down the exhaust line. The cat-back also has the springs you're looking for but can't find. On the non-EX/SI models the cataltic converter is attached directly to (underneath) the manifold and looks like a bee-hive (for lack of better description), From there it's a straight run into the muffler.

If your current 02 sensor has been in for a few years you'll be lucky to get it out without destroying the threads, as they can get heat welded to the manifold. Do your headers have a hole for the primary 02 sensor but not a secondary one? If, that is the case and you're worried about throwing a CEL.. I think a second hole can be drilled and threaded (tap & die set) about 3 feet down the exhaust line and the use the double defouler setup (OBD2 only). Again, I am not 100% sure of this.. so, hopefully others will chime in.

It looks like you may be someone who's been banned before or caused controversy so, I probably just wasted my typing talent on this.

 

Hondrix is correct but you would be much better off welding a bung vs tapping for the secondary. As long as the guy used anti seize you should be able to get it out. My opinion would be to buy a test pipe as they already have the secondary bung and have a magnaflow "high flow" cat welded into the test pipe in order to keep your emissions in legalized state but get that performance I'm assuming you're looking for. Thats my .02 this is about $120 setup and legal

If you wanna go without a cat run your exhaust as is and as I stated above run a 90degree defouler that has different size holes you can try(small, med, large) because every car is different and you don't know which size hole in the defouler will work to satisfy your ecu. But this will not be emmission legal but will keep your cel off and engine happy. The secondary simply tells the ecu if the cat is going bad. The primary or upstream is very important and tells the car how to run the correct afr. They are two different part numbers for the upstream and downstream on your car as well.
This is about a $35 setup but not legal