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All About Exhaust Systems

2

Comments

  • margaret3margaret3 Member Posts: 1
    At least once a day when driving my 2006 Honda CRV, I get the strong rotten eggs smell that I associate with a catalytic converter problem. It last a couple of minutes.

    The problem is, it is intermittent. I am afraid if I take it to the dealer, they will say "unable to duplicate the problem." Any suggestions?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Try a different brand of gas as an experiment. Also could be that on start up your engine is running a bit rich. Might need some adjustments.
  • shoughunshoughun Member Posts: 4
    When I had the same problem with my VW exhaust I just made sure that it is still under warranty... Or else I have to pay for it... In your case, if it was tampered, you better look for a new one...
  • 0patience0patience Member Posts: 1,712
    I was wondering y there are 3 cats on this car
    For emissions.
    and if i take the front 2 off will it be able to pass smog if the back cat is brand new.
    No, any alterations to the exhaust are illegal and any missing parts are an automatic fail.
    and does anyone know which one of the 3 fails the most.
    Usually the rear one.
  • fbpatriot14fbpatriot14 Member Posts: 5
    How can you tell if a cat is clogged? If a cat is clogged can it rob horse power and gas milelage?
  • paisanpaisan Member Posts: 21,181
    No, any alterations to the exhaust are illegal and any missing parts are an automatic fail.

    I'm not so sure about that. If you were to replace the cats with high-flowing cats that still allowed the vehicle to pass emissions and no CELs then it would not be illegal. You cannot remove them however if the emissions would increase due to it.

    -mike
  • 0patience0patience Member Posts: 1,712
    Ok, I made my statement too broad I guess.
    Only approved replacment parts may be used, which some cat back systems and high flows are approved.
    Removing a cat would be a violation.

    Removing the pre-cats/mini-cats on his vehicle would be a violation.

    If there is no DEQ inspection, then that may be a different story for them. Federal guidelines talk about alterations, removal and that, but their state may have other guidelines that they go by.
  • oldfarmer50oldfarmer50 Member Posts: 22,646
    I was looking at the Magnaflow web site and according to them it will boost my hp by 11 and increase torque almost as much. Plus it has a nice sound.

    My question, is there any downside to these systems such as lower gas mileage? Would the intake need to be modified in any way?

    2019 Kia Soul+, 2015 Mustang GT, 2013 Ford F-150, 2000 Chrysler Sebring convertible

  • okko1okko1 Member Posts: 327
    well the way it works with me is the better it sounds the faster i drive it and the fuel mileage seems to follow a downward trend. but if it sounds cool thats what your buying you will never feel the hp or torque at 11 anyway
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    There is no horsepower inside a muffler. The most HP gain would be from no muffler at all. These mufflers would only increase your horsepower if your stock system were heavily restricted. If this is a cat-back system only I think those numbers are very optimistic indeed. If you are installing exhaust headers, free-flow catalytic and mufflers, then yeah, you might get 8-10 HP on a large displacement engine.
  • oldfarmer50oldfarmer50 Member Posts: 22,646
    So what you are saying is, unless you like the sound it's not worth it?

    The engine in question is a 3.8L with single exhaust. Don't know if it's restricted but stock it's rated at 263hp.
    The Magnaflow site has some dyno charts to "prove" the horsepower and torque gains.

    2019 Kia Soul+, 2015 Mustang GT, 2013 Ford F-150, 2000 Chrysler Sebring convertible

  • paisanpaisan Member Posts: 21,181
    I'm going to agree with mr. shiftright. I'd look at dyno numbers on the specific exhaust on your specific car. Generally you need intake, exhaust, hi-flow cat, and catback to get 8-12hp gain. Sound of course is a different story, which is what exhaust is mostly used for in a very general terms. There are *some* exhausts that will net you 20-30hp but those cases are rare.

    -mike
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Well if these mufflers are behind the catalytic, I don't see where any horsepower is coming from unless you have a cantaloupe stuck in there or something.

    I suppose if your stock muffler is restrictive you could gain maybe...what...1-2HP...but you won't feel it.

    Nothing wrong if you are just buying "sound". Sound is nice. I like sound.

    As for the dyno tests, this is a whole can of worms. I am not implying duplicity...sometimes it's just human error. You might find this interesting:

    http://www.turbomagazine.com/tech/0402tur_dyno_tricks_problems/index.html
  • paisanpaisan Member Posts: 21,181
    What I meant in terms of dyno test are take the car stock, dyno it with the exhaust, drop the exhaust, bolt on the "new one" and re-dyno (don't even take the dyno off the car) and you might see some increases, but usually they only work in conjunction with other flow-mods (headers, Downpipes, High Flow Cats, Intake, etc)

    -mike
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Yep, you have to look at the intake/engine/exhaust as ONE BIG TUBE....if you are going to open the back end and you haven't done anything to the front or middle, your results are not going to be very fruitful. In fact, if you open the back TOO much, you'll create negative effects.
  • chelle26chelle26 Member Posts: 8
    just having troubles with exhaust system..has anybody familiar with exhaust system kit canada? had someone tried installing it before or on eBay?
  • cr8tvt2cr8tvt2 Member Posts: 1
    just wondering if anyone can help me!!! I'm searching for a catalytic converter for my truck. Its 2001 full size montero. (y-pipe) Admissions: Federal.
  • spiker50spiker50 Member Posts: 3
    I would like to know what would be the best aftermarket system to use for performance and gas mileage improvement for my 2005 4.0 V6 Ranger 4X4.
  • uwishucoulduwishucould Member Posts: 1
    Does anyone know what to disconnect to run straight headers on an 07 mustang v6?
  • 0patience0patience Member Posts: 1,712
    Unless you have it professionally done, you are looking at major headaches.
    A lot of sensors have fits when you change the exhaust system without changing the programming.
    If it were me, I'd leave it alone. Nothing good can come of it.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Not a great idea. You need the 02 sensors to talk to the computer.
  • burdawgburdawg Member Posts: 1,524
    At the most you should only put a cat-back system on it. In my own opinion though it's a waste of money, especially on the V6.
  • obyoneobyone Member Posts: 7,841
    Aftermarket companies knowing of the problems when removing O2 sensors have manufactured "dummy" sensors which replicate a cars performance under ideal situations which tricks the computer to believing that everything is working fine. Course if you have an emissions problem you would never know as the O2 sensors would report that everything is as it should be.

    I live in a non-emission testing state which would make it more reasonable to use the dummy O2 sensors and remove the cats completely which makes for better exhaust then adding a catback as we know that the cats are way more restrictive than any muffler.
  • paisanpaisan Member Posts: 21,181
    I live in a non-emission testing state which would make it more reasonable to use the dummy O2 sensors and remove the cats completely which makes for better exhaust then adding a catback as we know that the cats are way more restrictive than any muffler.

    Despite the fact that they don't test, you are still federally mandated IIRC to have a cat on your car. A High-Flow cat would accomplish both sides of the coin while not giving the all-out best performance it would significantly increase it while keeping you compliant.

    -mike
    Motorsports and Modifications Host
  • obyoneobyone Member Posts: 7,841
    LOL!! I guess that's why they stopped selling those straight pipes on ebay.
  • Karen_SKaren_S Member Posts: 5,092
    A reporter would like to talk with anyone who recently have used aftermarket products that provide better fuel economy, such as the Tornado Fuel Saver and fuel-line modifications like air bleeders and magnets. The reporter would also like to hear from people who have tried oil and fuel additives or exhaust-system modifications as well. Please respond to ctalati@edmunds.com with your daytime contact information and what you used no later than Tuesday, June 3rd.
  • oldfarmer50oldfarmer50 Member Posts: 22,646
    I have a 12 year old Chrysler with 105K miles on the original exhaust system. To say that I'm pleased would be an understatement.

    At some point these components have to wear out. Does any one know what Chrysler used to get such longevity out of their system?

    I'd like to replace it with something as good if I can.

    2019 Kia Soul+, 2015 Mustang GT, 2013 Ford F-150, 2000 Chrysler Sebring convertible

  • obyoneobyone Member Posts: 7,841
    Since the coming of unleaded fuel, most exhaust systems are designed to last the life of the vehicle. If that were true where are Midas and Meineke getting all their customers from?

    If you're happy with the results from the oem system I'd go back and install the same. That way you'll get a system that will last at least another 12+ years. Twenty five years on two systems is impressive. :surprise:
  • djcaprondjcapron Member Posts: 2
  • jspirojspiro Member Posts: 1
    I'm in the middle of replacing the head gaskets on a 1994 Toyota 4 runner and the manual tells me to remove the exhaust crossover manifold.
    I cannot see how they expect me to get access since it is between the engine and firewall?
    Does anyone have any experience removing this manifold or whether it is actually necessary to remove to get the heads off?
    Thanks for any advice.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    So it's a 6 cylinder?

    Well that's what the book says:

    "Remove the 6 nuts, crossover pipe and 2 gaskets."

    Have you removed the intake manifold and stripped everything else off the top that you need to? Maybe that's how you gain access.
  • srs_49srs_49 Member Posts: 1,394
    Sorry for the untimely reply, but...

    I never had to touch any of the exhaust components (pipes, muffler, cat, hangars) on my '94 Dodge Caravan. That was in something like 174,00o miles of driving over 11 years (got rid of it back in 2005).
  • gabrieltellinggabrieltelling Member Posts: 1
    I have an 02 GMC sierra 4x4 with a 5.3. It has two catalytics, one per pipe, then the pipes Y together into the muffler. I, being a carpenter, took my sawzall and cut the muffler off and replaced it with a 30" section of straight pipe. The truck sounds fantastic, and of course it feels like it has more horsepower. But I'm getting 16.5 mpg on the interstate. My neighbor has a 99 silverado all factory and he gets 20.
    So, I am trying to sort this exhaust business out. I do not need more horsepower than the truck comes with from the factory. What I am interested in is sound and mpg.
    What is a 'tuned' exhaust? Does it do something that I can't by merely buying 2 mufflers and having my mechanic make true dual exhaust?
    Am I gaining anything other than sound with true duals vs. single muffler? Does one flowmaster perform better than one factory muffler, or is it just the sound factor?
    What if I bought a chip and left the exhaust as is? Would the chip compensate for the loss of back-pressure and re-tune the engine in a way that recovers mpg?

    There are so many options and variables, I don't even know what to base a decision on. Again, what I want is best mpg, best setup for the longevity of the engine, and some sound. Oh yeah, and I don't want to spend more $ than I'm going to get back over the life of the truck. Simple right?

    Thanks, Gabriel
  • obyoneobyone Member Posts: 7,841
    Sawzall eh?

    You don't state what your mileage was before hacking the exhaust. Plus your neighbor's version of the 5.3 produces less hp than the '02. One thing I can pretty much guarantee is that there is virtually no hp gain nor significant mileage increase over stock with a catback "tuned" for your truck. Forget the flowmasters. They will crap out within 4-5 years forcing you do buy another. Plus they will get you less mpg than you're getting now.

    Corsa and Borla make the best exhaust systems. They will outlive your truck. Install one of those and forget about it if what you're looking for is a loud but no resonance exhaust.

    Am I gaining anything other than sound with true duals vs. single muffler? Does one flowmaster perform better than one factory muffler, or is it just the sound factor?


    True duals will lose low end torque and lower mpg. Flowmasters will create more problems than you would want.

    What if I bought a chip and left the exhaust as is? Would the chip compensate for the loss of back-pressure and re-tune the engine in a way that recovers mpg?

    A chip may give you an increase in HP depending on which one you get. It will not increase mpg nor compensate for your sawzall job.

    Oh yeah, and I don't want to spend more $ than I'm going to get back over the life of the truck. Simple right?

    Yes and no. The cheapest route and perhaps the most effective at this point would be to install a Borla or Corsa muffler. Might not be tuned specifically for your truck but some of them will make your truck sound like it has a big block. Assuming that's what you want. Check out some of the online sellers for the muffler and if you have a mig welder you can do the install yourself. Wait. Sorry you're a carpenter not a welder. Well take it to a muffler shop and they can weld it on for you.

    I'm surprised that your truck doesn't give you any problems since it lacks a muffler.
  • allenjacksonallenjackson Member Posts: 4
    There are two types of manifold restriction. With manifolds in-hand, look inside one of the two "T" junction ports. You will see the slots in the main tube. That slot material is one type of restriction. The 2nd type is present in all 3 ports. Put your finger inside any of the three ports, and feel for a raised welded bead at the opening where the tube itself is welded to the flange. If you measure the holes in the engine head, and compare that dimension to the inside diameter of a clean manifold tube, you will note them to be about the same.
  • 2000exped2000exped Member Posts: 1
    I have a 2000 Ford Expedition 4.6L with about 150,000 miles on it. I was driving and I'm not positive but I think I heard a pop, kinda like a cork from a wine bottle, then I heard what sounds like a belt flapping or as I read on another post, sounds like a chopper. I pulled over and looked under the hood. A usual DIYer co-worker says it sounds like the exhaust, but can't tell for sure. It starts up fine, but the chopper sound is noticeable and loud (not like metal hitting metal). For a while before this happened I was hearing a ticking sound when it is idleing, not really noticable when driving just mostly when idleing and sometimes the truck rattled, but not all the time. Not sure if all these are tied together with the chopper sound. I've never had work done on the exhaust other than installing an aftermarket exhaust. I managed to drive it into a parking lot, but afraid it would do more harm driving it to a repair shop and until I can figure out what the problem could possibly be and have it towed. Do you have any suggestions as to what the cause of the sound could be? Could it be the exhaust manifold?
  • socalrccprixsocalrccprix Member Posts: 6
    all exhaust has a database and how tos if you run into a problem with installation they have every single exhaust, header, and muffler. Yoiu can also try searching youtube for your year make and model and the exhaust part you want for install videos.
  • kiawahkiawah Member Posts: 3,666
    Well you need a mechanic to look at it, could be a number of things.

    If you heard a loud metal hitting metal sound prior to the pop, it could have been internal engine parts (like from the valves or piston/crankshaft), and then a 'pop', which could have been a backfire/explosion from unburned gas which got dumped into the exhaust pipe where it ignited and exploded.

    Shouldn't have been driving it with making a loud noise like that.
  • mg45mg45 Member Posts: 8
    Hello, i am new to this forum and this is my first post. I have a 1999 saturn SL2 that is getting miserable gas mileage, 12 mpg! I have been calculating the gas mileage by setting the trip ODO and driving miles driven by gallons used, as well as by the gauge and using a few iphone apps. Im getting a max of 150 miles per tank.

    I noticed today that when i rev the car, it sounds very "ricey". I am thinking maybe the catalytic converter is falling apart, like some pieces of the "honey comb" inside the converter. Maybe this is causing my bad mileage? I would love to replace it in a heartbeat, but as you know it's not the cheapest thing to replace. But if the cat is the problem, it will be replaced ASAP. Below is a link to a video i made tonight with the exhaust sound on my 99' SL2. Below the link is a list of all the things i have done/replaced on the car in trying to fix this issue.

    If you like, give it a watch, or listen and tell me what you think it could be. Also the exhaust pipe and muffler from behind the cat has been replaced back in april when i bought the car, due to a nice rust hole at the first bend behind after the cat. The car doesn't have any loss of power, just the ricey noise and bad gas mileage. Here is the link:

    http://www.youtube.com/watch?v=NxO3bKbJ-MM

    Here what i have done:

    Transmission was rebuilt at 78,000k due to reverse slam and burnt fluid, current mileage is 84,200k

    Exhaust pipe after the Cat has been replaced.
    ECTS and connector
    AIT and connector
    Thermostat, and radiator flush
    Fuel filter
    Injectors have been cleaned
    Spark plugs replaced with NGK coppers and wires
    Map sensor
    PCV Valve
    Front Oxygen Sensor, OEM not spliced.
    Cold air intake

    The car doesn't burn a drop of oil and is always up to date on oil changes. Any help would be great!
  • srs_49srs_49 Member Posts: 1,394
    Is your check engine light (CEL) on? If so, did you have the OBD-II codes read? That's the first step in diagnosing anything on a post 1996 vehicle.

    Without any codes to go by, I would replace the front O2 sensor (though I see that you already did that), though if that were bad it should set the CEL. It could also be a vacuum leak which lets more air into the intake. That might causes the ECU to dump more fuel into the engine in order to keep the air-fuel ratio without bounds. These are just guesses.
  • mg45mg45 Member Posts: 8
    Thanks for the reply. There are no engine or service lights lit on the dash.I had the car car scanned for codes at auto zone a few times but no codes are coming up.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Okay, so then we sit down and play Sherlock.

    What throws no codes on an engine that sounds like it is running well, but could result in awful gas mileage?

    (I'm thinkin' I'm thinkin' :confuse: )

    Excessive fuel pressure from the FP regulator?

    Leaking injectors?

    Not shifting into high gear?
  • kiawahkiawah Member Posts: 3,666
    - Dragging brake pistons, or mis-adjusted parking brake.
    - underinflated tires
    - my first thought when I heard that whinning, was a bearing going bad on air compressor, waterpump, or alternator
    - and that is a really throaty exhaust tone....got any back pressure?

    What is the color on the interior of the tail pipe? Is it a really rich black substance, showing as running too rich?
  • mg45mg45 Member Posts: 8
    I jacked up each wheel today and the brakes are not sticking. The tires also have 32psi listed on the tag in the door jam. I removed the front o2 sensor and the car drove the same if not worse, so i don't think the cat is clogged. I also put my hand over the tailpipe, but it kept getting pushed off from the pressure, so once again i don't think thats clogged.

    The inside of the taipipe does have a good amount of black substance, that it actually left a black line going down the exhaust pipe and onto the muffler, but the car is not blowing black smoke. I also removed the spark plugs and took some photos of each, as well as the exhaust pipe. Here are the photos:

    http://img20.imageshack.us/gal.php?g=96655802.jpg">
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    You're running rich all right.
  • mg45mg45 Member Posts: 8
    Ok, as you can see from my first post those are all the things ive replaced. What should i do next? The only sensor i haven't replaced is the cat o2 sensor, but there are no engine lights on. Im thinking injectors? Should i pay the 65 bucks to have them professionally removed and cleaned, or could it be something else as well?
  • watkinstwatkinst Member Posts: 119
    It's a saturn!

    Any chance its leaking gas when its rolling down the road? I worked for saturn in the early years. Only saturns that didn't burn oil were the ones in the shop getting the fuel pumps replaced or the one's at the scrap yard being scrapped. Hence not running.

    Later years the Honda motors were nice but the rest was well what can I say GM parts.

    Its a fuel system issue not an exhaust issue or break issue or tire issue. Given your car has no engine lights on would indicate that the car has more than just a fuel system issue given the GOV mandated engine management systems are failing to pick up an obvious fuel issue. When was the last time you had it smoged? Did it pass?

    The fuel goes some place :-)

    Is your kid or neighbor syphoning your tank? I'd consider that a very big possibility given its nearly impossible for that car to burn that much fuel without very obvious problems.

    Get a locking gas cap! See if your milege improves - they cost like $8 :-)
  • mg45mg45 Member Posts: 8
    I tried that before except with a clear piece of tape on the gas tank cover at night to see if anyone was siphoning my gas. As for leaks, i looked under the car while it was running and after a drive but i don't see anything leaking, (one of the first things i suspected. I also revved it while looking underneath but once again, i didn't see any leaks. Are there any special places i should look for leaks at that are most likely going to leak? What about the pictures i posted, does it look like it's running rich? Also I've been getting this gas mileage since day one when i got the car in April 2009. It was inspected then and passed. I live in New York and its due for inspection in April.

    Don't they just hook something up to the OBDII and scan for codes? And if nothing comes up then they pass the car? Thats what all the mechanics i talked to over here said, unless the car is older and doesn't have OBDII. Here are the pics again:

    http://img20.imageshack.us/gal.php?g=96655802.jpg
  • watkinstwatkinst Member Posts: 119
    No engine lights - would mean essentially no codes to pull if NY inspection is only doing a non run - check the codes inspection. I'm not familiar with NY inspections.

    Do you live in the city? I didn't know people owned cars there? HA HA Wife lived in NY for 7 yrs.
  • srs_49srs_49 Member Posts: 1,394
    The cat O2 sensor (in back of the cat) has nothing to do with how the car runs. It's just there to monitor the efficiency of the catalytic converter. It's there to make sure the cat is doing its emissions thing.

    Shifty/anyone else - Don't you think if he's running that much excessive fuel through the engine, it would fry the cat in short order, and so set the CEL? Cat's are not tolerant of fuel-rich exhausts, IIRC.
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