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All About Exhaust Systems



  • oldfarmer50oldfarmer50 Posts: 10,195
    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.

    2015 Mustang GT, 2009 PT Cruiser, 2004 Chevy Van

  • paisanpaisan 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.

  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,570
    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:

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  • paisanpaisan 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)

  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,570
    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.

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  • just having troubles with exhaust system..has anybody familiar with exhaust system kit canada? had someone tried installing it before or on eBay?
  • 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.
  • 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.
  • Does anyone know what to disconnect to run straight headers on an 07 mustang v6?
  • 0patience0patience Oregon CoastPosts: 1,616
    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 Sonoma, CaliforniaPosts: 57,570
    Not a great idea. You need the 02 sensors to talk to the computer.

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  • burdawgburdawg 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 Posts: 8,054
    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 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.

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  • obyoneobyone Posts: 8,054
    LOL!! I guess that's why they stopped selling those straight pipes on ebay.
  • Karen_SKaren_S Posts: 5,094
    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 with your daytime contact information and what you used no later than Tuesday, June 3rd.

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  • oldfarmer50oldfarmer50 Posts: 10,195
    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.

    2015 Mustang GT, 2009 PT Cruiser, 2004 Chevy Van

  • obyoneobyone Posts: 8,054
    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:
  • 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 Sonoma, CaliforniaPosts: 57,570
    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.

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  • srs_49srs_49 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).
  • 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 Posts: 8,054
    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.
  • 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 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?
  • 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 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 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:

    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 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.
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