2009 Honda Accord Exhaust pipes

Tiny
SCHAIS53
  • MEMBER
  • 2009 HONDA ACCORD
  • 2.4L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 60,000 MILES
About 7 months ago I got my first car, a 2009 honda accord lx-s blue with black wheels and a loud exhaust which appeared to be a cat back. Now that I look back I should've thought harder about it because I have put in a good bit of money fixing small nicks and nacks well anyway, the 2.4 liter honda accords stock come with a single exhaust system and mine has duals, but not true duals, the previous owner of my accord seemed to have removed the muffler, resonator and the catalytic converter, and added a seperate pipe to make "duals", he added aftermarket magnaflow tips as well. My question is, could I cut off the added pipe and reweld the hole that will be left and then order something like a skunk2 3" muffler and cut down the original exhaust pipe and make a custom exaust, or would I be better off completely removing the entire exhaust system as a whole and ordering a new one like a greddy exhaust or something? I do not want duals, I want just a single exhaust like my car was built to have.

NOTE: my car is pretty low so I wasnt able to really get a good picture of the spot of the weld.
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Wednesday, January 22nd, 2014 AT 6:18 PM

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Tiny
CARADIODOC
  • EXPERT
You have two things to consider. First, there has to be an oxygen sensor before the catalytic converter, the converter, and a second oxygen sensor after it. The Engine Computer watches both sensors switch between "rich" and "lean". The first one switches up to around two times per second. If the converter is working properly, the second sensor will switch much slower, perhaps once per minute. When the converter loses its efficiency, no change in the exhaust gas takes place in it, so the gas going out is the same as the gas going in, and the two sensors switch at the same rate. By the time that occurs, the computer will have already detected the loss in efficiency, set a diagnostic fault code, and turned on the Check Engine light to tell you. If the catalytic converter is removed, that code will set. If either oxygen sensor is removed, different codes will be set related to those, and again, the Check Engine light will be on. If a new problem shows up, you'll never know because the light is already on. A very minor problem with a simple fix can easily turn into an expensive one. Also, when some fault codes are already in memory, the computer will suspend some self-tests that use things related to those codes for comparison, so you could have a running problem with no fault code to direct you to the circuit or system that needs further diagnosis. You would have to repair everything related to the fault codes set for the missing exhaust parts, then try to drive the car and hope codes set related to the new running problem. There's over a thousand potential fault codes. Without a code to indicate the circuit or system with the problem, or the unacceptable operating condition, it's impossible to know where to start the diagnosis.

The second problem is that the suspension ride height has been altered. Regardless of the illusion you get when you drive the car, you have decreased stopping ability and handling, and tire wear will increase. I will gladly go into all the details, but I would never buy or own a lowered car or raised truck. You can be sure lawyers and insurance investigators know about altered ride height and will use it to their advantage when the other guy caused a crash by running the red light. They will convince a jury that you were partly at fault for the crash because you were less able to avoid it, ... And they will be right.

The things that have been affected are "scrub radius" and weight transfer during braking. The only people who lower cars are those who don't understand how these things were designed-in by the manufacturer. Automotive sales is extremely competitive, and if the manufacturer thought they could gain market share by offering raised trucks and lowered cars, you can be sure they would do it. They know it can't be done while maintaining safety, and they don't want to be party to a potential lawsuit that they know is coming if the vehicle is involved in a crash, regardless of who was at fault.
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Wednesday, January 22nd, 2014 AT 6:51 PM
Tiny
SCHAIS53
  • MEMBER
The ride height of my car has nothing to do with the question I asked, nor was your answer.

Again, I have a pre-owned vehicle with self welded duals (I DID NOT DO THIS) my question is could I cut off the added pipe and close the hole and just add my own muffler. Or should I just replace the whole exhaust system as a whole with an aftermarket cat back
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Wednesday, January 22nd, 2014 AT 8:21 PM
Tiny
CARADIODOC
  • EXPERT
I know you didn't do this, but you bought a vehicle from someone who did, and that means it was not done by a professional. I have no way of knowing what is on your car or how the work was done. You can cut and weld anything, but unless you're a much better welder than I am, you're going to burn through the metal and make a mess of it. I can't do it, so it's likely you can't do it, and no professional is going to risk his job trying to modify any part of an emissions system. That leaves you with factory parts that can be bolted and clamped together. If you have emissions testing in your area, you need the factory exhaust system to be legal, and this conversation is moot. If the parts are rusty or made of stainless steel, welding on it becomes even more frustrating. Even if you do a half-way decent job of welding on a patch, if there's a pinhole leak and the car is involved in a serious crash, don't think that won't be discovered and come up in the courtroom. What would you think of me if I did NOT make you aware of this?

For the suspension, I gave you some information that you weren't aware of that could save you a lot of grief in the future but you chose to be upset. You don't have to be grateful that I cared enough to take the time to make you aware of the same things all mechanics have to keep in mind when they work on people's cars. I would be happy to paste a copy of my really long and in-depth reply on this subject so at least you will be an informed consumer. If that is just going to make you more angry, I'll leave you on your own and hope you never end up sitting in a courtroom for a crash that was not your fault. Lawyers are real good at turning things around. You won't be any better off not knowing about these things.

After rereading your original post, I see all you said is the car is low, not that it was lowered. Sorry if I read something in that wasn't there. The information is still worth sharing so more people become aware of the pitfalls of modifying anything on a car.

To get back to the exhaust system, you said, "i want just a single exhaust like my car was built to have". So does the government. You didn't say if the oxygen sensors are still on the car, and you didn't say if the Check Engine light is on or if it works. You also didn't say if you care about fuel mileage and a clean-running engine. Without knowing these and other things, it's impossible to know what is the best answer I can give you. All I can do is explain how things are supposed to work and hope that's enough that YOU can make an informed decision.
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Wednesday, January 22nd, 2014 AT 9:00 PM
Tiny
SCHAIS53
  • MEMBER
Thank you for your convenience. So by reading what your saying now is pretty helpful, I think we could both agree that the existing exhaust set up isnt worth the time/labor. I will probably just replace the whole system with a new cat back system. I was just curious to see if it would be worth ordering an oem resonator and catalytic converter and fixing it myself. Unless its possible to cut off at the cat and resonator brackets and just replace the cat, resonator and the exhaust pipes/muffler/tip. It just seems more expensive but I know for a fact I could do it cheaper but im thinking that its better off to get an aftermarket cat back so that way I could pass emissions tests.
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Wednesday, January 22nd, 2014 AT 9:24 PM
Tiny
CARADIODOC
  • EXPERT
I don't know what your skill level is or what you have for tools but I can offer some observations. I worked for seven years in a Sears Auto Center doing mostly exhaust work and suspension and alignment repairs, so the mechanical part of exhaust work doesn't scare me. Being attached to a shopping mall, we weren't allowed to have a torch or a welder so we had to cut everything apart with air tools, and clamp all the new parts together. Some shops only weld new pipes together which takes a lot longer, but if you're good at it, there won't be any leaks. The big drawback is when a curved pipe hits something and you have to turn it a little. You can do that by loosening a clamp, but you can't once it's welded.

That was in the '80s when oxygen sensors were fairly new yet and not real complicated. Relatively few places outside of California had emissions testing at that time. There were no O2 sensors after the catalytic converters until 1996.

After 2000, I attended a lot of high-level training classes covering engine performance and emissions diagnosis. One of the things I remember about Hondas is they started using seven-wire oxygen sensors that were real expensive. They're doing a lot more with them than other manufacturers need to do, and replacement sensors from aftermarket suppliers were not working as well as they needed to. To insure the system would work properly, you needed to use only original parts, and they are expensive. For that reason, if you still have the original catalytic converter on the car, don't replace it if it is not needed. What you need is the O2 sensor in front of the converter, and another one right after it. What comes after that doesn't matter. Hondas also typically use a braided steel flex hose under or near the engine. That is another piece you definitely do not want to replace unless it is absolutely needed. Those cost over $400.00 in the early '80s.

Most cars now come with stainless steel exhaust pipes which are expensive. Most replacement pipes from auto parts stores are much less expensive but will rust out every few years. I have all the original stainless steel pipes on my '88 Grand Caravan daily driver, up here in road salt country, but the muffler finally broke apart seven years ago. It lasted 18 years, but the cheap hardware store replacements lasted two years each. Not sure if I was better off with three $40.00 replacements, and crawling on a granite driveway to replace them, or if I should have bought the $100.00 stainless steel replacement from the dealer, with the right hanger brackets welded on, and saved a lot of aggravation.

Another advantage to using original pipes is the hanger brackets will be welded on already and will match the rubber isolators on the car. That will insure the system can rock and wiggle around without hitting anything or transmitting vibrations into the body. Always start at the front, one pipe at a time, and just clamp it lightly at first to hold it in position. Once all the parts are installed, tweak them as necessary, then start tightening them from the front and work your way to the rear. Don't over-tighten the clamps. That will crush the pipes and cause leaks.
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Wednesday, January 22nd, 2014 AT 10:24 PM

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