Will A High Flow Catalytic Converter Make My 2009 Honda Civic Louder And A Little More Power

Is it okay to drill holes in my catalytic converter?

Your “friend” is an idiot.A cat will pose no significant restriction. There is no gain in performance.If you drill holes into it you fool the oxygen sensors into thinking the mixture is lean. That will tell the ECU to command more fuel and it will skew fuel trims. You will get a “check engine light” and pay $ 80.00 in my shop just for the knowledge that you are an idiot.You will come to my shop after having been to Autozone , where they scanned your car for free and sold you an oxygen sensor you didn’t need in the first place.Why are you doing this? Why do you want your car to sound louder?Loud cars are owned by idiots.If you want to get laid then read books. Become literate . Go to the library and make eye contact with intelligent dames. Driving around in the neighborhood with a hole in the muffler ain’t gonna get you laid.

If I took off the catalytic converter, will it make my fuel get better mileage?

Don't listen to the naysayers. A engine is a pump, anything you do to increase pump efficiency, is going to increase gas mileage. A new cat will not rais fuel consumption much, But if it has over 100,000 miles on it, You will see a marked increase or “restoration” of gas milage. This is especially true of cars with a secondary air pump. They are not exactly filtering the air, before its pumped into you exhaust.This is what gets fun. If you reprogram, or modify the O2 sensors signal to bring the engine to stylometric fuel ratio or just less, you will get a 5–10% increase in gas milage. This trick really shines in stop and go traffic. If you analyse the wave form of the upstream O2 sensors, you will notice it spends a lot more time rich, than lean. You are sitting at red lights feeding that Fat Cat, so it can make more smoke.All cars are set up to fuel that catalytic convert. This keeps them hot and working. Without extra fuel pumped thru the engine, that cat has nothing to do, cools down, and slowly plugs up. To bad your cat will plug up if you lean out the engine. Hint, Hint……….

What problems go along with a bad catalytic converter?

A clogged catalytic convertor causes the symptoms of a loss of power when accelerating or going up a hill. This is an often overlooked cause of loss of power, can cause check engine fault codes and lights, and mechanics will often change a few parts unnecessarily , especially if it is only partially plugged. A couple ways I check for plugged cats when a low power complaint is a symptom, and other obvious basic maintenance items have been checked for service is to have someone hold the rpm at about 1800 to 2000 steady. Then check for a good push of exhaust with my hand from behind the tailpipe. A plugged or partially plugged cat typically leaves a hot sickly feeling exhaust flow from the tailpipe. Compare to a known good working car nearby, known to be performing properly and with the same amount of cylinders. That slow , hot sickly flow at 2000 rpm compared to the hard push blowing your hand away of a not clogged cat is a dead giveaway, and I have NEVER misdiagnosed a plugged cat , or made false diagnosis with this method. Another way is watching a vacuum gauge connected to the intake manifold. When revving up, if the exhaust is plugged the gauge reading will climb then begin to slowly drop as the exhaust pressure builds up. Further testing will be needed to verify which part of the exhaust is plugged. Diagnostic by codes is unreliable and until now I had not heard of it. A code p420 only refers to catalyst efficiency. And can be set by faulty o2 sensors. Removing the exhaust and testing for engine power returning to normal works. But the hot sickly flow has been most accurate with my experience, in several cases where shops had missed it, were stumped and called me to come check. They are always embarrassed for missing the simplicity, but need not, as cars and their complicated electronics and even age old problems can lead to loss of power without any immediately obvious cause.

Will it cause problems with my car if I cut off the catalytic converter and put a straight pipe in its place?

It will add performance but hurt fuel economy and your ability to pass emissions.The CAT is a great invention, but it adds an obstruction to the exhaust. If you remove obstructions you will realize some performance benefit (could be major or minor depending on the car, probably only major if large powerful engine to start).The problem is your car (if it’s less than 20 years old) uses inputs from the oxygen sensors to modify the air fuel mix. There is an oxygen sensor before the CAT and one after the CAT to measure how good of a job it is doing. If you remove the CAT you will get an error code (check engine light). On most cars this means your engine will probably not run as good (certainly not as efficiently) because without those inputs from the oxygen sensor it won’t dynamically modify the air fuel mix and the spark timing, it will just run off of presets as if the car is still warming up (open loop vs closed loop).The error code will also prevent you from passing emissions (which most states require) and the lack of a CAT will be noticed by most emissions testing facilities that use cameras nowadays to make sure it has not been removed.Most people ask this kind of question to bypass emissions (rather than to improve performance). If your goal is to bypass emissions, it won’t work. CATs are expensive because they are made of platinum and palladium and a few other expensive materials. It is illegal to sell a used catalytic converter but some people do it anyway.If you’re asking for performance modification reasons, your best bet is to buy a less restrictive performance exhaust system that has a CAT and spots for the oxygen sensors.