I have an 05 altima se-r. I love it. I have headers and greedy exhaust, but I put them on as soon as I bought my car. It now has 29000 miles on it. I have an acceleration problem when I hit the throttle. My car bogs real bad now and this started about a week ago. I have also noticed my engine temp is a little warmer. My mechanic says he thinks the catalytic converter is plugging up or is bad. I'm gonna replace it but what I really want to know is how much or if any backpressure is needed for my car to performe well.
My other question is will I have to recalibrate my cars cpu when I install my larger injectors?

Thanks josh

 

well your mechanic is right about your cat going bad you can go on ebay and buy a test pipe to replace the cat but it will throw a low catalyst check engine light code and also it will fail your local emissions test and or state inspection. if you go with a test pipe buy a o2 sensor simulator from www.o2simulator.com and splice it into your secondary o2 sensor after the cat. your engine temp is going to go up cause of that clogged cat. and and your car will perform better if you have lower backpreasure. to help lower your underhood temp. get your header thermal coated or get header heat wrap (looks ugly but does the job). well hope this helps