I have been using the N1 exhaust with the test pipe for a whole day before I got the check engine light come on. Now I removed the test pipe and replaced it with the factory cat.

Heres my question, anyone who tried using the test pipe then switched back to the cat notice a change in sound? when I had the test pipe on, at vtec I would hear something like a F1 car sound but after I put back my cat, vtec sounded like the engine roared louder but the exhaust go silent, I am confused, please let me know your experience with this exhaust, nonetheless its the best sounding exhaust.

 

there isn't an issue here. the cat is a straight through pipe that goes through a catalytic filter to reduce emissions and it will tone down the sound by muffling it slightly.

and as far as your engine's noise is concerned, its probably because you can hear it now.

 

s2kpunisher,

I have the Spoon exhaust, but neglected to put on the test pipe for the same reasons as you experienced, the Check engine light. Now I plan on putting the test pipe on this weekend, for I found a bulletproof solution. I found a electrician for cars that makes a module that tricks the ecu into thinking the O2 sensor is reading perfectly fine. The while sensor is replaced, and you have no check engine light, so your car is running at optimum, instead of safe mode.....

Nick

 

I dont think I'll be running the test pipe ever again since its illegal and I heard its a federal crime that carries a $3k fine.

 

Do the straight pipe, only if you are off road or in competition.
Not only you have to deal with dodgin the emission law, your car will guzzle gas like crazy. Not worth the trouble in my opinion.
Strangely though, you can still drive around the check engine light.
You may suffer some problem early but with more time and more driving, your car will behave normal again vtec and all with check engine light still on. I guess ECU stabilizes over time.

 

I found a way around the CEL. I have a test pipe on, and no check engine light. What I did was weld another O2 sensor mount on top of the existing one on the test pipe. The O2 sensor doesn't sit directly in the flow of the exhaust now, it sits a couple of millimeters away from the direct flow. I guess its getting less of a reading now. Drove for a about 2 weeks now, and no check engine light. But I'm about to switch it back out for the cat, I get all paranoid when theres cops around.