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Will An Exhaust System or Muffler Improve Gas Mileage?

Exhaust system and muffler manufacturers make a lot of claims about their products. Understandably, consumers are a little skeptical when an exhaust kit claims to both increase horsepower AND improve gas mileage. After all, aren’t performance and gas mileage mutually exclusive?

The thing is, mufflers and exhaust systems DO improve gas mileage. Here’s why:

1. Exhaust systems and performance mufflers don’t add power – they improve efficiency.

Almost every new vehicle comes with a restrictive factory exhaust system. The reason? Restrictive exhausts are both quiet to the ears and inexpensive to build. Since automakers are building cars for everyone – and since some people decidedly don’t want a car that makes noise – factory exhaust systems are usually designed to be quiet. Because automakers cut costs on exhaust systems, this quietness is achieved by making a restrictive system.

Factory exhaust systems are restrictiveA restrictive factory exhaust pipe. Image copyright Ben Frantz Dale

When a factory exhaust is replaced with an after market muffler or cat-back system, there’s less restriction in the exhaust. “Less restriction” means the engine exhales a little easier. This improves efficiency, and that means the engine suddenly has a little more power. However, nothing was “added” – the additional power was always there. You just needed a better exhaust system to find it.

2. Efficiency isn’t just about horsepower

An efficient engine isn’t¬†necessarily¬†powerful. For example, the gas engine in a hybrid is incredibly efficient, but rarely are these engines considered “powerful.” Efficiency means that an engine gets as much energy as possible out of the diesel or gasoline it uses for fuel. Therefore, improvements in efficiency improve power…but what if that power isn’t used to go faster?

Engine efficiency means more power and better mileageSpeedometer image copyright PowerBookTrance

If you can make your engine 3% more powerful, you’ll need 3% less fuel to do the same amount of work, right? Exhaust systems, depending on the system or muffler you choose and the vehicle they’re installed on, typically improve power by about 2-5%. If you’re driving a 2008 Ford F-150, for example, your truck probably gets about 16mpg. Adding an exhaust system might improve power 3%. If you don’t use that extra power to go faster and drive the exact same way you did before, you’ll see a 3% improvement in fuel economy.

A 3% fuel economy improvement on an 08′ F150 with an exhaust system means about a 0.5 mpg gas mileage improvement. While that might not sound like much, consider this: If gas costs $3 a gallon, and your drive this truck 15,000 miles a year, you’re saving yourself about $85 a year on gas. In five years, you’ll have saved nearly enough money to pay for a complete cat-back exhaust system.

Not to mention that you’ve got an extra 3% of power when you need it (like while towing or hauling), or the fact that your truck will sound a lot meaner too.

3. Small cars can benefit the most

If you have a truck with a big V8, your engine is so powerful that it can push past a restrictive factory exhaust system pretty easily. However, if you have a small displacement 4-cylinder, adding a less-restrictive muffler can boost efficiency tremendously – sometimes as much as 10% (only 5% is more common). Adding an HKS Hi-Power exhaust to a 2005 Subaru WRX improves power output about 8%, which means fuel economy should improve by about 2mpg.

Obviously, boosting fuel economy by 2 mpg is going to help pay off a new exhaust system pretty quickly.

Bottom Line: Adding an after-market performance muffler or exhaust system will improve engine efficiency from 2-10%. Improvements in efficiency can be used to either increase horsepower or improve fuel economy.

Whether this efficiency is used to go faster or to get better fuel economy is up to you and your foot!

143 Comments Post a comment
  1. Donnie smith
    Apr 19 2012

    I have a 2007 Jeep compass, 4×4… What muffler/ exost system will improve gas mileage the most, for the money???

    Thanx, Donnie smith

    Reply
    • Jason
      Apr 19 2012

      Donnie – The testing I’ve done for TundaHeadquarters.com shows that most exhaust systems have minimal impact on fuel economy. If you’re trying to boost gas mileage, you might look at a cold air intake system first. However, if you’ve got the money, adding a quality cat-back exhaust system can add a few hp and improve mileage.

      Reply
      • Donnie smith
        Apr 19 2012

        Yea I installed a K&N cold air intake kit with a mass flow filter last month but it didn’t seem to have much effect (went from 23mpg to 25mpg)… Any other tricks?

        Reply
        • Jason
          Apr 19 2012

          Donnie – That’s pretty good – +2mpg is big as a percentage!! ;-)

          Other ideas:

          - Power programmer, many of which allow you to program a “fuel saver” mode. Might give you another 1-2 mpg (maybe just 1mpg)
          - Full synthetic oil, as thin as you can buy (you can probably run 0W-20 instead of 5W-20 without any ill effects) – might get you another 1mpg
          - Run a bottle of fuel injector cleaner through the gas tank every 30k miles (won’t help but will make sure you’re not hurting yourself with a dirty injector)
          - Check your tire pressure regularly…this can make a big difference if one of your tires is low
          - Switch to low rolling resistance (LRR) tires…you won’t handle as well off-road and/or in the snow, but you’ll definitely save gas. Most LRR tires boost MPGs 2-3% (+1mpg)
          - Cat-back exhaust might be good for 1mpg, only it might not do anything, so it wouldn’t be my first choice
          - Some people have had success using this weird little device called the “fuel doctor”, including a Tundra owner named Toby – http://www.tundraheadquarters.com/blog/2011/05/25/fuel-doctor-initial-test-results/

          Mostly, however, the best way to boost fuel economy is to get something that gets better gas mileage. :-)

          Good luck!!

          Reply
        • MICHAEL
          Dec 7 2012

          Hi donnie , although I drive OLDER RANGER 4X4 KING CAB 4X4 4.0 liter , I HAVE USED THE ACETONE TRICK AND NOTICED MY TACH SAYS I AM USING ALMOST 500 LESS RPM ON THE HIGHWAY AT 75 MPH PLUS ABOUT200 LESS RPM AT IDLE some say it can hurt the injectors , and I am by no means a gearhead I WOULD SERIOULSY TRY THAT . THEY CLAIM THE ACETONE PURE 100 PERCENT BTW WHICH IS EXTREMELY CHEAP REDUCES THE SURFACE TENSION OFTHE FUEL , WHICH ENABLES ITTO BURN EASIER AND MORE EFFECIENTLY .

          Reply
          • Jason
            Dec 8 2012

            Michael – Just a quick note – acetone is a plastic solvent. It’s not *if* it’s going to hurt your injectors and fuel system, it’s *when*.

          • james
            Feb 11 2013

            thats impossible for your rpms to be lower on the motorway , your either a fool or a liar. The engines rpm directly corresponds to the road speed depending on the gear your in. unless you were driving in 4th on the motorway then after adding acetone decided to drive in 5th gear. what your saying is you actually went slower on the motorway since adding acetone which is just plain retarded.
            your idle however may change depending on your ECU

        • scott
          Aug 4 2013

          Little late on conversation but 2 mpg from just addimg air intake is pretty good. You won’t get that much with most aftermarket parts. Especially if you were driving a real man’s vehicle. Lol. JK

          Reply
      • Drew
        Jul 2 2014

        Any pros or cons to adding an after market exhaust brand new compared to a used one off craigslist?

        Reply
        • Jason
          Jul 7 2014

          Drew – A craigslist sourced exhaust can be a great way to save money. Just make sure there aren’t any leaks or clogs.

          Reply
  2. Jeff
    Jun 19 2012

    I have a 2000 honda accord coupe V6. If I replace the stock part with a magnaflow caddlac converter and catback system how much would this improve my gas mileage? also what other modifications could i add to help my honda and its gas mileage?

    Reply
    • Jason
      Jun 21 2012

      Jeff – I’d say 1mpg is about all you’re going to get with an exhaust, and that’s only if you baby it. If you combine the exhaust with an air intake and a performance chip, however, you might be able to squeeze another 3-4mpg out…even more if you go with low rolling resistance tires and if you drive like a little old lady.

      Reply
  3. Daniel Amos
    Jul 8 2012

    I have changed the rear box of my exhaust, will this give a better Fuel Economy?

    Reply
    • Jason
      Jul 9 2012

      Daniel – I don’t really understand what you’re saying (rear box is the tip maybe?), but generally speaking exhaust system changes have little effect on gas mileage good or bad.

      Reply
  4. joel
    Jul 11 2012

    Read what it said about exhausts on small cars
    I just purchased a magnaflow exhaust and soon will get an intake
    For my 2.2 cavalier
    Wondering how much you think I’ll get in mpg

    Reply
    • Jason
      Jul 12 2012

      Joel – It’s harder to move the needle on small cars, as they’re already pretty efficient. Still, 1-2 mpg is possible.

      Reply
  5. Donnie smith
    Jul 12 2012

    Hello, I have a 2004 Honda Civic Hybrid…
    I have installed NGK lazer eridium plugs, a K&N air filter, new
    Mobile1 full syn oil (0w-20), and I tip. I want to make it louder and faster! I have ran completely out of ideas on how do do that without effecting the mpg! It’s getting between 35-45mpg at the moment and everybody says that since in is a hybrid (with a 1.3l, 79.3cubic inch gas engine, and a 1300cc electric motor) that if I put an intake system or an exoast system it will go haywire and destroy my gas mileage!? Please help! Any thoughts or suggestions???

    Reply
    • Mark
      Jul 18 2012

      you dont buy a civic hybrid if you want to go fast.

      Reply
      • Donnie
        Jul 18 2012

        I didn’t buy it, got it for free! And I don’t have the cash to but something better

        Reply
  6. dan
    Oct 1 2012

    I have a 1997 Honda Accord coupe. I recently replaced my old, rusted out muffler with a brand new stock muffler. Will my vehicle gain any mpg?

    Reply
    • Jason
      Oct 11 2012

      Dan – Possibly. If the old rusted out muffler was blocking exhaust flow, the answer is yes.

      Reply
  7. Pete
    Oct 11 2012

    I have a 2006 Tacoma, if I add a cold air intake and a cat-back exhaust will I have problems with the computer? The last thing I need is to have CEL or spending the money just to have it run poorly.

    Reply
    • Jason
      Oct 11 2012

      Pete – Adding an exhaust system will have no impact on your engine computer – the only component in the exhaust system that the computer pays any attention to is the oxygen sensor, and that’s mounted into the exhaust manifold…if you’re doing a cat-back exhaust, nothing to worry about.

      As for a cold air intake, the only concern is that you don’t use an over-oiled filter. If you buy a filter that requires periodic cleaning, you have to be really careful when re-applying the oil to the filter. If you put too much oil on, it can coat the mass air flow (MAF) sensor and cause a check-engine warning.

      But if you guy with an oil-less filter (AEM and aFe both offer intakes that use lifetime filters which don’t need to be oiled) you’re good to go.

      Reply
      • Pete
        Oct 11 2012

        Thanks…I’m going to add both and see if it will help improve gas mileage. Not looking for miracles but anything is better than 18mpg.

        Reply
  8. Austin stueland
    Oct 12 2012

    I just put a glasspack on my oo Saturn sl2. I’ve noticed a major drop in fuel efficiency. How can this be?

    Reply
    • Jason
      Oct 13 2012

      Austin – Not sure. Shouldn’t have caused a major change in fuel economy, unless it’s clogged. You might pull it off and take a look.

      Reply
  9. Yvee
    Oct 22 2012

    So I have a 2004 audi a4 1.8t turbo Quattro and was planning to get a magnaflow exhaust system, and was wondering how much more mpg will that give me? I’m current getting an ave of 500 km a tank and I drive mostly highway! And how much will a k&n air intake mpg increase will I get?

    Reply
    • Jason
      Oct 22 2012

      Yvee – As the article says, new exhaust systems can improve fuel efficiency from 2-10%. In terms of real-world improvement, 1-2 mpg isn’t unheard of, but improvements of 1mpg or less are most common for both exhaust systems and upgraded air intakes/air filters. I’m not sure what 1-2 mpg is in L/100km, but I’m sure you can figure that out. :-)

      Reply
  10. Phillip
    Nov 8 2012

    Jason, I have a 2005 Audi S4, that is completely stock. 6 speed manual transmission, 4.2 Liter V8 dual exhaust. tire size is 235/40 Z R18. I plan on keeping the car for a long time, and am interested in making it more fuel effecient and getting some more horsepower. Can you guide me in the most cost effective way to acheive this? Im interested in performance computer chips, exhuast systems, tires, other?

    Thanks,

    Phil

    Reply
    • Jason
      Nov 8 2012

      Phil – First, nice car! Second, not that you asked, but I’d look into carbon deposit cleaning systems…there’s a system called Terraclean that you might check out if you’re concerned about it. Three, the best levers you can pull are 1) intake 2) exhaust 3) programming, preferably a map that is adjusted for whatever intake and exhaust you choose.

      Otherwise, there’s not a lot you need to do. The S4 is already very well “optimized” and really doesn’t need anything. That’s the beauty of buying an already fast car. Unless you’re up for spending lots of money on pricey upgrades, I’d stick with those three.

      Reply
  11. Marcus
    Nov 16 2012

    I have a 09 Jeep Wrangler that I installed an AirAid intake on and my mpg went from 17 to 19. I then installed a Dynomax axel back exhaust system and the mpg went to about 15. Is that normal? I lifted it 2 inches and put bigger tires now it’s down to about 14.5. I can understand the losing mpg with the lift and tires, but the exhaust I don’t get.

    Reply
    • Jason
      Nov 18 2012

      Marcus – Not common to see exhaust systems effect gas mileage more than 1-2 mpg either way…they’re important, but they’re not that important. :-)

      My guess is that either a) your engine computer is still adjusting to the new air intake or b) you got some very good mileage prior to installing the exhaust that threw things off.

      Gas mileage is notoriously inconsistent.

      Reply
  12. Brian
    Dec 12 2012

    I have a 2012 Ford Focus SE (sedan; 5-speed manual). What would you recommend to me to help improve efficiency & power?

    I also wouldn’t mind my engine/exhaust having a bit more sound to it!

    Reply
  13. john
    Dec 20 2012

    Hi, i just bought an sel ’12 focus and i am really planning on upgraging my intake and exhaust, will thesemodifications void my warranty??? And 2nd what is the difference between named brands exhaust systems and the custom exhaust systems that is made in our local muffler shop?? Ty

    John

    Reply
    • Jason
      Dec 20 2012

      John – First of all, modifications to exhaust and intake don’t effect warranty (only your local dealer will probably tell you that they do). See this post for more info: http://www.tundraheadquarters.com/blog/after-market-accessories-new-warranty/

      Second, the main difference between systems sold by Magnaflow or Flowmaster and systems from your local shop is tuning. Cat-back systems sold by these big name manufacturers are carefully tuned to maximize power. Systems sold by your local muffler shop are not carefully tuned, but this is not to say that they can’t be powerful. Often times your local muffler shop can get very close to a perfect tune just because they a) have a lot of experience and b) they pay attention to what the big names are doing on their kits.

      My advice is to contact your local autocross club and see what local muffler shop(s) they recommend. This will help you make sure you work with an exhaust shop that understands tuning.

      Reply
  14. Allen scott
    Jan 13 2013

    the best was to get better gas mileage is to switch to 100 percent pure octaine Caroline. Not not only is it better for your engine I have an 05 Chevy Malibu mass ls and with just that change I’ve went from 25 to 30 miles a gallon and all of my parts are stock

    Reply
    • Jason
      Jan 14 2013

      Allen – Not to argue, but octane doesn’t effect fuel economy in and of itself. If your engine is getting better fuel economy after switching from regular to premium, it’s likely a tuning or injector performance issue. Premium fuels have more detergents than regular, and a faulty or degraded oxygen sensor can sometimes lead to better performance with higher octanes…you might get your vehicle checked out (the local auto parts store will pull codes for free if you don’t have your own reader).

      Reply
  15. James
    Jan 14 2013

    Hi I have a new 2012 Dodge Ram with the HEMI. Surprisingly I was averaging about 19.5 to 20 mpg on the highway. I recently changed out my stock muffler and replaced with a performance muffler. Now I am averaging 16.5 on the highway at very bust. I have been a dodge truck driver for years and know these trucks dont always get good milage. What could have caused this decrease???

    Reply
    • Jason
      Jan 14 2013

      James – If you swapped out your muffler right about the time winter started, that would explain the lost in MPG. Winter is bad for your mileage, partially because of the cold, partially because winter fuel is a little less potent, partially because you might spend more time letting your vehicle to idle and warm-up, etc.

      Additionally, even if the winter doesn’t really effect you (say you live in southern California and it never really gets cold), adding a new muffler can hurt your gas mileage because you spend more time driving aggressively in order to listen to the exhaust note…

      However, as a general rule, adding an exhaust system isn’t going to effect your gas mileage dramatically unless there’s something wrong. A clogged muffler is about all you have to worry about (and that’s unlikely), but otherwise the very worst system won’t effect you more than 1mpg or so (and vice versa).

      Reply
  16. Patrick
    Jan 22 2013

    Hey Jason,
    Great article, thank you. Based on it, I believe a new exhaust could benefit my ’99 Rav4 (4cyl). Especially since the previous owner told me the exhaust will “need to be replaced soon” and already “has a clamp on it”. I don’t know what/where the clamp is/does, but I imagine this is causing me to get the poor mileage (~20mpg highway!) I’m getting.
    Do you think I’ll get near the 10% you mentioned was possible with my situation? Which exhaust should I get? Cost? Install cost price range?

    Thank you for your help,
    Patrick

    Reply
    • Jason
      Jan 22 2013

      Patrick – If your existing exhaust system is clogged or restricted somehow (rust can really plug them up), replacing the system from the cat back (i.e. everything behind the catalytic converter) is a good idea.

      As for fuel economy improvement, it’s tough to say. Older vehicles can suffer from poor mileage for a lot of reasons that have nothing to do with your exhaust. My suggestion? Get with a trusted local mechanic and see what they have to say.

      Reply
  17. Vince
    Jan 24 2013

    Hello, what are your expectations if I were to replace the entire exhaust system in my 1993 Toyota Corolla 7afe? I live in the middle of Texas where temperatures are fairly high to most of the year, and the previous exhaust system has rusted 20 years, and the car is considered compact-subcompact for its less than 2000 lb weight. What are the expected gains?

    Reply
    • Jason
      Jan 24 2013

      Vince – 3-5% of base rated HP with a new, performance after-market system. However, finding a performance system for a Corolla is tough. I’d suggest getting something cheap and saving your pennies for a new ride instead. ;-)

      Reply
  18. Mike
    Jan 31 2013

    I have a stock 1988 ford crown vic I’m to purchase in a few weeks and i’d like to know if going with the k&n cold air intake system how much of an increase in mpg will I have and what other tricks I can use to increase gas mileage

    Reply
  19. dalton
    Feb 21 2013

    I have a 2002 mercury cougar 2.5L v6..
    id like to a get a magnaflow dual exhaust system and have it installed.
    can anyone tell me how much this would cost and how to go about doing it?
    I’m looking for more horse power or torque and a manly rumble

    Reply
  20. Dallas
    Feb 22 2013

    I’m running a 97 dodge avenger v6 on the factory exhaust system, and I’m looking to swap out the muffler. The motivation for this is hoping to improve performance a bit, yet a muffler that gave my car more of a muscly rumble would be nice. Not looking for an outstandingly loud noise, that’s unappealing.
    I was hoping someone more experienced could point me in the direction of a muffler that’d fit my car, and would give it that sound and performance boost.

    Thanks!

    Reply
    • Jason
      Feb 23 2013

      Dallas – Any number of mufflers will fit, but most of them will just make your V6 sound louder. It’s hard to get a “rumble” out of a V6, and when you do, it’s usually by adding a dual with a cross-pipe (helps mellow out the higher frequencies). If you just want to buy a muffler (and I don’t blame you, as I think that’s a prudent compromise), I’d suggest finding a good local muffler shop and letting them install the muffler they think is best.

      Also, after the muffler is installed, it might take 500-1000 miles before you really hear how it’s going to sound.

      Reply
  21. Brian
    Mar 23 2013

    Jason, I was wondering why it would take 500-1000 miles to hear how the muffler would truly sound. I have a 1998 Ford Mustang with no muffler, and am trying to find something that sounds the way I like.

    Reply
    • Jason
      Mar 25 2013

      Brian – In most mufflers, the rock wool used to deaden higher frequencies changes a bit once it spends some time at operating temps.

      If you have a muffler that doesn’t use rock wool (like a magnaflow muffler), than you probably won’t notice any change.

      Reply
  22. Mag
    Mar 24 2013

    Hi I was wondering..I installed a yonaka full catback on my automatic trans 01 Acura integra LS… the exhaust diameter is about 2.3 inch… I feel like when i drive it makes my car slower..and it is kind of loud.. is that because the pipe is way too big or the cat back exhaust is not good for automatic transmission car? thank you

    Reply
    • Jason
      Mar 25 2013

      Mag – Unless you’re measuring the change scientifically (i.e. at the drag strip or on the dyno), than I’d say that your cat-back system is probably helping you.

      Now, if your system was designed for an Integra with a more powerful motor (say a GS-R instead of an LS), than you could see a loss…but again, without data, it’s just conjecture.

      Finally, exhausts can help vehicles with both manuals and automatics. It makes no difference. :-)

      Reply
  23. rodger
    Mar 31 2013

    am burning a lot of fuel what is the best muffler system can i used to held .it as a muffler system straight from manifold to a cherry bomb them comes a 2′pipe to a drum then to a double tail pipe

    Reply
    • Jason
      Apr 1 2013

      Rodger – Is there a question in here? Didn’t they teach you punctuation and grammar in school? :-)

      Reply
  24. gareth case
    Apr 10 2013

    I bought a used car 98 corrola and realised a buzzing sound coming from the engine whenever i accelerate. i realised that bolt was broken at the exhaust manifold and I replaced. I am still hearing the sound. upon closer inspection I saw that the previous changed the head pipe and put in a rather “squeezed” one with a reduced diameter. Could that be causing the buzzing sound?

    Reply
    • Jason
      Apr 12 2013

      gareth – Hard to know. Internet diagnosis is notoriously unreliable…I’d get it looked at by a professional.

      Reply
  25. Ian
    Apr 15 2013

    I own a 2005 Subaru impreza wrx 2.0 turbo.
    Just wanted to know whats the best brand of muffler to install that will give me that Subaru sound and also improve on fuel efficiency?

    Reply
    • Jason
      Apr 15 2013

      Ian – There’s rarely a difference in performance from one brand to another – the difference is in design and tuning resources and materials used to make the muffler. My standard advice is to buy something from Flowmaster, Magnaflow, or Borla. All three companies have plenty of money for R&D and make a good product.

      Having said that, I’d cruise the WRX forums for a boutique brand that offers a cat-back exhaust system and a new downpipe…I’ve seen some impressive performance improvements on a WRX with those add-ons.

      Reply
  26. Yee Hou
    Apr 16 2013

    Hi Jason,

    I am currently driving an I4 Honda. Being a Honda, the torque band is quite high up, and I’d like to lower it by using a longer exhaust manifold.

    For reference, its a D15B7 engine with a fixed timing cam so I doubt it would be aggressive, but without taking the engine apart I can’t tell for sure if there is any valve overlap.

    Understanding that a longer exhaust manifold promotes better exhaust evacuation, I’m wondering will it get to the extend of drawing clean air into the exhaust manifold (thus affecting consumption via O2 sensor)? If that would be the case, I’m guessing I would need a variable resister put on the O2 line?

    Thank you :)

    Reply
    • Jason
      Apr 16 2013

      Yee – Generally speaking, long-tube headers reduce low-end performance. I’m not sure that longer tubes are going to accomplish your goal.

      As for changing the O2 sensor to compensate for increased scavenging, I’d say no. The increase isn’t likely to be substantial across the entire RPM range…it’s only going to effect things in a certain band. You could replace the O2 sensor to try and get a little boost in a specific range, but it makes far more sense (IMHO) to make this adjustment by tuning the ECM.

      Finally, it’s all but certain that your Honda has some valve overlap. Most engines do.

      Reply
      • Yee Hou
        Apr 16 2013

        Hey Jason,

        I got the idea of longer manifolds increasing low-end torque from a combination of http://www.mazda.com/mazdaspirit/skyactiv/engine/skyactiv-g.html, and a whole lot of other pages which I don’t remember.

        Not to sound like I’m doubting you, but from your understanding what do longer exhaust manifolds do?

        Thanks :)

        Reply
        • Jason
          Apr 16 2013

          Long tubes increase exhaust velocity, but that’s not really a good thing on most engines between idle and 3500 RPM (or so). The reason? Your exhaust system is technically over-sized for your vehicle at these lower RPM ranges. Therefore, increasing the velocity effectively increases the size of your already over-sized exhaust. This means that you lose low-end torque…I’ve seen this happen on truck engines numerous times. Long-tube headers hurt gas engines on the low end.

          Conversely, your exhaust system is typically undersized at the top RPM range. If you throw some long-tube headers on, you’ll get better performance above 4,000 RPM. This is great for adding HP, but again I’m not sure that you’re looking for more HP.

          Now it’s important to understand that engine designers can change head design and valve timing to accommodate a specific header. Mazda may very well have been able to increase low and mid-range performance with long-tube headers, but only because they changed the timing and tune

          Exhaust systems are the last component in a very complex chain. As a general rule, the best thing you can do is purchase a cat-back exhaust system and/or exhaust manifold that’s specifically designed for your vehicle. Once you’ve purchased these things, you can use an after-market tuning system to maximize power.

          In other words, don’t over-think it. Unless you’ve got the tools to measure and model the exhaust stream, you’re spinning your wheels. Just go with the setup recommended by Greddy (or whomever you’re buying your parts from) and call it good. ;-)

          Reply
          • Yee Hou
            Apr 18 2013

            Thanks Jason for all this insight.

            This is very helpful. Cheers!

  27. Chris
    Apr 25 2013

    Just installed a airaid system on my 2011 f250 gas .I get about 2.3 miles per gallon more when the truck is empty.i also pull a trailer that’s about 10000 pounds. When I’m towing it gets about 1.3 mpg better on the highway .

    Reply
  28. Daniel
    Apr 30 2013

    I have the new 2013 Toyota Rav 4 with a 4 cylinder. I want to improve the exhaust system to get a deeper sound, but NOT real loud, also better milage would be nice. What do you recommend…THANKS…

    Reply
    • Jason
      May 9 2013

      Daniel – Sorry, no idea. Hard to get what you’re looking for with a 4cylinder.

      Reply
  29. chubbz
    May 15 2013

    Hi,

    I have a 1998 toyota corolla , rsi shape and was wondering if adding branches and an exhaust system will effect my fuel or rather improve it? all i want is a better performance and sound with out effecting my fuel intake.

    Reply
    • Jason
      May 15 2013

      chubbz – Provided you size an exhaust system upgrade correctly, it will not hurt fuel economy.

      Reply
  30. chubbz
    May 15 2013

    Jason_What do you mean by size is correctly bru? and what about branches added as well ?

    Reply
  31. jon
    May 19 2013

    i have a 93 mustang fully built high compression 306 cold air 73mm maf and tb headers catless exhaust with flowmasters i get 8mpg highway im gona take a guess that there is nothing i can do to improve mgp without loosing power at this point

    Reply
    • Jason
      May 20 2013

      jon – It’s not like swapping out mufflers was going to make your 8mpg Mustang (which sounds awesome, btw) a 20mpg cruiser! ;-)

      Frankly, I don’t think there’s anything you can do to the exhaust in this specific case that would make a noticeable difference. You might look into using a programmer to run in an “economy” mode when you’re not at the track…assuming you can re-adjust back to your tuned mode when it’s time to go fast.

      Reply
  32. Martin Stewart
    Jun 1 2013

    Hi Jason,
    My wifes 2004 Ranger 4.0 L Super Cab 4×4 usually gets 16 to 17 mpg ( read on a Scan Gauge I have installed in it) all of a sudden we are getting 19 mpg. This is a good problem to have. Driving home on a110 mile route where we usually get 17 mpg I got 19.2 mpg again as read on the Scan Gauge and this is heavily loaded as usual. The only thing I can think of that is different is that about 500 miles ago at the start of a 400 mile trip the muffler blew out with a fist sized hole in it. I heard this when she got back from the trip and was planning to have the muffler replaced but after this most recent 110 mile trip maybe I need a less restrictive muffler. Your thoughts?
    Martin

    Reply
    • Jason
      Jun 3 2013

      Martin – Could have been a restriction in the muffler, could be the muffler itself. OEM mufflers – especially as they age – can become clogged with rust and “junk” and underperform.

      Glad to hear you’re getting 20% fuel economy!

      Reply
      • Martin Stewart
        Jun 4 2013

        Do you know what would be the least expensive way to replace that muffler with something that acts as if it has the big hole in it but is quieter?
        Thanks,
        Martin

        Reply
        • Jason
          Jun 4 2013

          Martin – A glass pack muffler costs as little as $20, and while it’s loud, it offers very little restriction. Your local muffler shop probably installs it for $100 or less.

          Reply
  33. Ahmed
    Jun 17 2013

    Hey there I’ve got a vauxhall astra CTDI life 1.3 diesel I was looking to make the car faster as it only reaches 100mph tops what can I do ? Add a turbo exhuast maybe ?

    Reply
    • Jason
      Jun 18 2013

      Ahmed – Sorry to say it, but there’s no replacement for displacement. If you’ve got a little motor, you’re only going to get a small amount of power. My advice is to save your money for a car with a bigger engine.

      Reply
  34. Jun 21 2013

    I have a 2002 Nissan maxima My exhaust is pretty much rusted out what exhaust system do you recommend for my vehicle I want sound ,mpg and performance thanks

    Reply
    • Jason
      Jun 21 2013

      ricky – Any cat-back system that’s designed for your make and model, budget permitting. I’d go with aluminized steel too due to the age of the vehicle.

      Reply
  35. Jun 21 2013

    Forgot a couple things lol 2002 Nissan maxima also an air intake ,and performance chip

    Reply
  36. Pablo
    Jun 26 2013

    I have a 1970 Chevelle sedan with a 350 V8 And I want to put a flowmaster 50 series on is, should I do it

    Reply
    • Jason
      Jun 26 2013

      Pablo – I don’t have any opinion on specific mufflers/setups. In my view they’re all pretty equivalent. What’s important is that you choose the right size and material.

      Reply
  37. jack
    Jun 27 2013

    I have a 2001 lincoln navigator. How can I get some improvements in fuel.

    Reply
    • Jason
      Jun 28 2013

      Jack – Short answer: trade it in.

      Long answer: Driver slower, accelerate as slowly as you can bear, remove any un-needed weight (like gear you’re not using, a 3rd row seat that isn’t being used regularly, etc), and make sure your tire pressure is correct.

      Exhaust system, air intake and/or performance air cleaner, and an engine tuner can help too…but only if you do all of the above.

      Reply
  38. K.S. Norman
    Jul 8 2013

    Jason, I have a 2007 Chevy Tahoe LT3. What would the best muffler to get improved flow, but without the drone and heavy rumble? I am also wondering about a K&N filter (not cold air intake) for it. I have heard mixed stories on the tack spay jacking up the MAS. True? Or is it worth it to put one in?

    Reply
    • Jason
      Jul 8 2013

      K.S. – I don’t have a specific recommendation regarding the muffler, but I will say that Borla systems tend to be a little better than the others in terms of drone/rumble.

      Only it’s all subjective.

      As for the K&N filters screwing up Mass Air Flow (MAF) sensors, it’s 97% exaggeration. New K&N filters have a small amount of oil on the cotton-gauze coating, the purpose of which is to catch particulates. The oil is perfectly applied at the factory – there’s no chance that excess oil will get sucked up into the engine and coat the MAF sensor.

      However, if you clean the filter yourself and re-apply the oil too liberally, you can have problems. Some MAF sensors are incredibly sensitive to this type of contamination. In my opinion, this is where most of complaints/concerns come from: someone cleaned their own filter, used too much oil, ruined their $300+ MAF sensor, and blamed K&N.

      Therefore, my advice is to clean your K&N filter sparingly (once every 50k miles), and to follow K&N’s cleaning instructions to the letter. If you do that, you’ll be perfectly happy with a K&N filter (they improve throttle response and improve fuel economy).

      Reply
      • David
        Jul 26 2013

        I have a 2005 Suburban with 33 inch all terrain tires 5.3L, 150,000 miles getting 13 mpg…If it were yours and you wanted to keep for at least 3 more years what would YOU do to it.??? i might pull a trailer or camper once a year, but better MPG is my goal.

        Reply
        • Jason
          Jul 28 2013

          David – Tires can make a big difference in fuel economy, especially large off-road tires with aggressive tread.

          Frankly, I’m not sure that you’ll be able to do much to get great mileage out of a Suburban. However, if it was me, I would think about less aggressive tread on my tires, make sure I had an after-market air filter or air intake, and invest in a programmer/tuner that had a fuel saving mode. Those changes will boost fuel economy without negatively impacting long-term wear and tear.

          Reply
  39. sam
    Jul 22 2013

    hey jason,
    im about to put a custom made cat back on my 03 Mitsubishi Triton 3.0 v6 will i recive much more power and torque that i will notice it 4wd?

    Reply
    • Jason
      Jul 22 2013

      Sam – Let me repeat that back to you: You’re installing a completely custom system and you want to know how this custom system that I’ve never seen will impact performance. Correct?

      Obviously, I have no idea. :-)

      Reply
  40. Larry D
    Jul 23 2013

    I have a 2009 toyota yaris sedan, i have installed an AFE cold air intake (dry filter), new tires, amsoil 5w30 and amsoil transmission fluid. getting 48.9 MPG right now driving speed limit. question is in you opinion will, a header pipe, and/or a cat-back exhaust actually be worth the $$ to get more MPG. Thanks Jason.

    Reply
    • Jason
      Jul 23 2013

      Larry – Nice job! 49mpg is impressive in any vehicle.

      While I think a header and tuned cat-back exhaust system might help you boost fuel economy a bit (1-3%), and eventually pay for itself, I don’t think you’re going to find these products on the after-market. Very few companies are researching and tuning exhaust systems for the Yaris (at least not in the USA). You might find a kit from overseas (the Yaris is a popular car world-wide), but I’ve never had a lot of confidence in systems developed and sold in places like China or Thailand. It’s not that these countries don’t produce quality products, it’s that I don’t think they’re using a strict R&D process.

      So, the answer to your question is “probably,” but it’s a moot point as there’s likely nothing you can buy that fits the bill.

      Reply
  41. jonat
    Sep 14 2013

    Good day. I just bought a surplus from japan a 2004 honda fit and i plan to change its original muffler into hks silent-power muffler. Does it affect its gas economy?

    Reply
  42. venancio
    Oct 15 2013

    Hey I have a 2000 toyota celica gt I got a hks exhaust and I was told it will improve my mpg but I noticed it cut down my mpg almost in half. My car used to last my 2 weeks driving 30-35 miles every day now it just lasts me 1 week. Any suggestions what can help? Maybe add a cold air intake? Or should I switch back to stock ?
    -thank you

    Reply
    • Jason
      Oct 15 2013

      venancio – You’re not the first person to say that an after-market exhaust system has hurt fuel economy, but I’ll tell you that it’s probably you that’s changed rather than the car. It’s natural to get into the gas more once you have an exhaust system, at least if you like the way it sounds. :-)

      If you don’t think that’s the problem, I’d suggest making sure that your exhaust system wasn’t damaged (specifically, the oxygen sensors and catalytic converters) during the upgrade, and that your engine computer wasn’t reset…sometimes shops disconnect the battery, which forces your engine to “re-program” and waste some fuel for a while.

      Reply
  43. Chris thorn
    Nov 8 2013

    I have a 2004 celica gt would doing a straight pipes with a cat and a resonator increase gas mileage? Or would cutting the muffler cause a decrease in mpg and power?

    Reply
    • Jason
      Nov 13 2013

      Chris – Straigh pipes and/or cutting a muffler off may or may not boost fuel economy. I would guess that it won’t help much either way…which is why I suggest buying a performance muffler over going with no muffler at all. The vehicle is designed to work with a certain amount of exhaust backpressure at various RPMs – if you change that pressure at your cruising RPM, you can reduce scavenging and/or increase backpressure, and that can hurt gas mileage.

      Besides, a performance muffler is cheap and will give you a great (yet legal) sign.

      Reply
  44. Hugo
    Nov 14 2013

    I got a 05 rsx, after i swap my exhaust and header, it cost me more on fuel. It could went up to 500km per tank, now i can only go around 450 or less. Last tank only went for 444.

    I just don’t got it.

    Reply
    • Jason
      Nov 14 2013

      Hugo – Could be the colder weather, could be that you’re driving more aggressively, could be that the engine is still adjusting to the new add-ons. I’d guess colder weather (and a cold weather fuel mix) based on the time of year (and assuming you’re in the Northern hemisphere).

      Reply
  45. CJ
    Nov 15 2013

    Hi Jason,
    This page is an awesome resource for this subject! Thanks so much (in advance) for your insight and assistance!
    I just picked up a ’10 Mazda CX9, 3.7l Dual exhaust. I discovered that the right side tip and muffler (damaged) are pushed in (backed into something?) so, I am looking at adding aftermarket “N1 style” mufflers. The OEM product is about $250+, while these Ebay A’pexi N1 knockoffs are $40. If I add these freer-flowing mufflers, without changing the remainder of the exhaust system from the cat, can I expect any increase in efficiency? I replaced the stock air filter with a standard (non-CAI) K&N filter and noticed a slight improvement. This is a CARB vehicle with CA emissions. I understand that this change may increase HP, but I’m more interested in MPG than sound or HP. 1-2 mpg over a year will more than pay for these.
    Cheers!

    Reply
    • Jason
      Nov 15 2013

      You probably won’t see much increase in efficiency or performance, but you might see a little (1mpg?).

      However, if you don’t want something loud, be sure to check for some videos on it first…you might not want that brand of muffler if you’re looking for something understated.

      Reply
      • CJ
        Nov 15 2013

        Hah! Yeah, I’ve been trying to find videos for anything similar to my car. However, I figure since I’m leaving both cats and the resonator, there still should be sufficient muffling of the sound.

        Regarding to your reply above, if the entire cat-back system were replaced, ie: 3″ pipe(s) & straighter/mandrel bends and high flow muffler, then I would see an increase? The muffler itself alone is not enough to warrant a significant decrease in back-pressure?
        Happy Friday!

        Reply
        • Jason
          Nov 15 2013

          CJ – The catalytic converters don’t really soak up much sound by themselves, so changing the muffler can make a big difference in sound.

          Also, a 3 inch system is almost certainly overkill for your CX9. A dual 1.75″ or 2″ system is a better fit…go too big and you’ll ruin low-end performance (and fuel economy).

          See http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/

          Reply
  46. peter carson
    Nov 30 2013

    Please correct me if iam wrong. But valve overlap is where the exhaust valve and intake valve are open at the same time,if the exhaust gas pressure is to low caused by the free flow muffler than more intake fuel can be sucked from the cylinder leaving less fuel to burn.Giving less power. I have seen exhaust pipe reduces put on the end of a exhaust system and the pwr.goes up. This might help Austin Stueland who left a comment

    Reply
    • Jason
      Dec 2 2013

      Peter – I think it’s the opposite. The free flowing exhaust has no (or almost no) negative pressure, so the exhaust system isn’t “sucking out” the combusted air and helping to suck in the clean air prior to combustion…thus causing poor performance.

      Reply
  47. Roger
    Dec 13 2013

    I have a 2004 BMW z4 2.5i, I currently have an aFe Dry Filter, Cold Air.Now I always shift at 2k RPM each gear, I try to save as much gas as I can. If I get this “Remus Exhaust” will that better my gas mileage + with my cold air?
    I believe if I buy high end products, I should not be to worried.
    link to the website, im getting it from
    http://www.bimmian.com/Remus-Sport-Exhaust-System-for-BMW-E85-Z4

    Reply
  48. CJ
    Dec 14 2013

    Jason,

    Would adding a removable silencer decrease the efficiency/add more back pressure? How effective (audibly) are silencers when used on high-flowing mufflers and do they detract from the performance?

    PS, I installed the after market N1 on my CX-9. It is louder in lower RPMs, esp inside the cab. I have already noticed an increase of about 2-3 MPGs based on previous readings. It does feel a little easier to drive. However, since it’s my wife’s car, it’s a little annoying to her, being a bit loud. Once you hit a steady speed, it’s almost unnoticeable compared to stock.

    Thanks for your time!

    Reply
    • CJ
      Dec 14 2013

      I should edit/amend that previous. It’s louder at lower speeds, while accelerating esp inside the cab. The higher the RPM, the less noticeable it becomes.

      Reply
    • Jason
      Dec 16 2013

      CJ – Probably wouldn’t have much of an impact.

      Reply
  49. Justin
    Dec 25 2013

    I have a 99 grand am se. 4 cyl. I drive about 30 miles to work everyday. I want to put a new muffler/exhaust on my car. I want to try to get better gas mileage but also have a better sound. It is worth makin a switch on my exhaust? If so will I be getting more or less mpg?

    Reply
    • Jason
      Jan 7 2014

      Justin – Most of the time, changing your exhaust system has minimal impact on fuel economy. 1-2 mpg, tops. That’s not a lot on a vehicle that already gets decent mileage.

      Thus, I’d probably focus my attention in other areas – specifically, driving with more emphasis on fuel conservation – as that will get you more impact.

      Reply
  50. James Ennis
    Jan 13 2014

    Since installing headers/dual exhaust on my 2010 5.7 Dodge Hemi 1500 truck, my engine light is on and indicates an O2 sensor problem.As long as the warning light remains on, the MDS feature and remote starter will not work.Should I replace the sensors?

    Reply
    • Jason
      Jan 13 2014

      James – It may be that you need to replace the sensor(s), but I’d check to make sure something wasn’t disconnected or damaged during install. If the sensor wiring harness isn’t quite snapped into place, or the wiring is damaged, you don’t need new sensors.

      How are the headers working out? Did you do a before and after dyno run?

      Reply
  51. David McAnee
    Feb 18 2014

    Will Toyota void warranty on a new 2013 Corolla if I change
    He muffler for a high performance muffler.

    Thanks

    Dave

    Reply
    • Jason
      Feb 18 2014

      No. First, because changing the muffler has no meaningful effect on the mechanical components of your vehicle. Second, it’s illegal for any manufacturer to void any warranty just because someone chooses to install a non-factory part.

      If, however, the muffler causes damage to the vehicle somehow (because it was installed incorrectly, it’s the wrong size, etc.), that won’t be warrant-able. But that is extremely rare.

      Reply
  52. jacob balthazor
    Mar 31 2014

    i have a 2000 kia sportage automatic 4 cylinder. if i were to add a thrush cherry bomb glasspack muffler onto it, would it decrease my gas mileage? would it make it sound like a truck or weird sound. Would it be bad for a fuel injected car.

    Reply
    • Jason
      Apr 1 2014

      jacob – Generally, adding a glasspack to a 4-banger sounds bad. It’s the “fart can” sound that a lot of people seem to hate. As for effecting mileage, it probably won’t push things too much either way.

      Unless you’ve got a turbocharged 4-cylinder, or you’re really going for the “sport import” sound, I’d suggest leaving your exhaust system alone. It’s only worth messing with an exhaust when you’re going to get power or cool sound. You’ll get neither with a naturally aspirated 4 cylinder.

      Reply
  53. Martin
    Apr 16 2014

    Hi Jason! I have a 2006 Honda Fit 1.3L and i want to improve my fuel consumption. Is it advisable for me to install new 4-2-1 headers and muffler? i want to get better fuel efficiency. Thanks!

    Reply
    • Jason
      Apr 17 2014

      Martin – My advice is to leave the exhaust manifold alone. The fit is already very fuel efficient, due in no small part to some careful exhaust manifold design. Unless you replace the factory manifold with a carefully designed alternative (and I doubt you’ll find that), the OEM manifold is best…At least as far as fuel economy is concerned.

      As for the muffler, you’ll be lucky to see any improvement. The exhaust isn’t really holding that vehicle back.

      Reply
      • Martin
        Apr 17 2014

        Thanks for your reply. What if i change the header up to the tailpipe to add power? would it improve my fuel consumption? My fit as of now is just doing 10-11km/L. i want to improve the fuel consumption.

        Reply
  54. david legaspi
    May 30 2014

    Hi Jason, Im thinking about replacing my stock Air Intake and Exhaust from my 2011 Toyota Tacoma V6 4×4 Pick-up with a TRD Cold Air Intake and Cat Back. Doing this, will it improve the HP and fuel efficiency? I hear both sides that its either a waste of money and can harm the engine, too its worth the buy and will improve the vehicles performance . Need your help to decide whats best.

    Dave

    Reply
    • Jason
      Jun 3 2014

      Dave – Harm your engine? No. Anyone who says that is either a dealership employee or absurdly paranoid. Some people argue that cotton gauze air filters let more particulates into the motor (and cause wear), but I have yet to see anyone prove that. So, like I said, no reason to worry about engine damage. At all. :)

      As for “waste of money,” you’re going to spend $500+ on an intake and exhaust (maybe twice that if you go TRD), and you’ll get maybe another 10-15hp, maybe another 10-15 lb-ft of torque, and (if you drive conservatively) another 1-2 mpg. To be completely honest, the ROI is poor. You can buy a lot of gas for $1,000, and the extra power won’t make a huge difference in most situations.

      However, if you’re looking for some additional fun, the sound of an aggressive exhaust and intake system has a value. I personally have no problem with spending my money that way, but I can see why some argue it’s a waste of money…

      Basically, it’s only a waste if you derive no pleasure from the sound or the extra power. :)

      Reply
  55. Chris Martin
    Jun 16 2014

    i recently got a 2010 Hyundai Genesis 4.6. while it is both comfortable and powerful, it could do with better mpg. how much would just cutting the mufflers off and adding straight sections of pipe increase or decrease my fuel efficiency?

    Reply
    • Jason
      Jun 17 2014

      Chris – Straight pipes rarely boost performance or fuel economy, at least not on a relatively unmodified street car. I would recommend a set of performance mufflers if you’re looking for sound, and if you’re looking for better gas mileage, I’d probably look at an after-market air filter and an engine tuner…exhaust doesn’t make a huge difference in fuel economy.

      Reply
  56. Robert
    Jun 18 2014

    I have a 2014 Toyota Tundra with a 5.7 liter V8 and wondered what is the best exhaust system for my truck. Don’t want anything to loud, but maybe hums. Any suggestions?

    Reply
    • Jason
      Jun 19 2014

      Robert – TRD’s system is probably the best option if you want something that adds some noise (and a little power) without ruining your commute with drone. I’d go that route if noise is a concern.

      A Borla kit is the other option.

      Reply
  57. BigDogg
    Jul 4 2014

    My ’07 Ford Taurus SE must have been really restricted. Ford said it makes 12 city 25 highway stock with the 3.0 V6. I replaced the cats, resonator, and muffler with high performance units and it runs 31mph at 65.

    Reply
  58. Robert
    Jul 7 2014

    Can someone help a Navy Vet ? Have a 2006 Toyota Rav 4 Sport. Muffler started deteriorating on the seams so I switched had the original stock muffler[ 32" x 14"] taken out and installed with a generic muffler that was about 2/3 [22" x 10"] the original size. Will this greatly affect the mpg? Would appreciate any feedback.

    Reply
    • Robert
      Jul 7 2014

      Forgot to include that it does seem that I am NOT getting better gas mileage, and actually spending more on gas. Could this be true?

      Reply
      • Matt
        Aug 5 2014

        Definitely possible. The smaller system will be more restrictive which can reduce the efficiency of the engine.

        Reply
  59. CJ
    Jul 8 2014

    Hey Jason,

    I’ve noticed you recommend *tuners* and *chips* fairly regularly to increase performance AND MPGs, while maintaining a frugal budget. Which ECU mods, tuners, chips etc would you say offer the best ROI?
    Do chips void warranties or harm the engine?

    Thanks again!

    ’10 CX9 3.7L – K&N, N1 Dual exhaust
    ’07 R56 Mini Cooper S – CAI/Short Ram

    Reply
    • Matt
      Aug 5 2014

      Chips don’t generally void the warranty. But, if something goes wrong and it can in any way be traced to the chip, the warranty won’t apply. Don’t expect to spend less than $300 on a chip if you want it to be any good. Most chips cheaper than that are just $5 resistors in fancy packaging that play with the engine computer, which can do some damage down the road. My recommendation, if you’re looking to get the right stuff for your vehicle, take it to a local tuner shop.

      Reply
  60. BigDogg
    Jul 8 2014

    Never heard of a tuner voiding a warranty. Did hear of a chip voiding the warranty because you actually modified the computer with an aftermarket chip.

    Reply
  61. Reggie
    Aug 2 2014

    Hi changed the catalytic converter on my Toyota camry 1997 v6 I realized a slight loud sound. Is it going to affect my speed and fuel consumption? Need an advice

    Reply
    • Jason
      Aug 3 2014

      Reggie – I’m not sure what you’re asking, but if you change your catalytic converter, it should only improve performance. If it doesn’t, it’s probably a good idea to check the oxygen sensors and connectors.

      Reply
  62. Gerry
    Aug 3 2014

    I have a 2011 Subaru Legacy 2.5i. I just did an axle-back swap from stock to a DC Sport muffler. Im wondering would this swap improve my acceleration? It seems to feel improved most when im driving on the highway. Could it be an improvement or just placebo? Thanks in advance!

    Reply
    • Jason
      Aug 3 2014

      Gerry – A lot of people notice improved throttle response, and it may be that you notice the improved performance on the highway. If you drive the same route every day, and you tend to notice these things, than I’d say you’re probably picking up on the increase.

      Reply
  63. Roger Arranguez
    Aug 12 2014

    I have a 2014.5 Camry SE Hybrid. I am converting the single exhaust to dual because it comes with the dual precut. I am actually doing this just for the looks. Anyway, is it better to install (I already bought the OEM muffler from toyota) it as a dummy/fake just attach to the existing system without cutting holes or really make it as a working exhaust. Any helpful advice is highly appreciated. Thanks

    Reply
    • Jason
      Aug 12 2014

      Roger – Hybrid exhaust systems are very carefully designed to be as efficient as possible from the factory. Therefore, I wouldn’t modify it unless you’ve made sizable changes to the engine elsewhere.

      Any change could negatively impact fuel economy and performance, so I’d just “fake” it and call it good. :)

      Reply
  64. David
    Aug 26 2014

    I have a 95 Chevy k1500 with a 5.7L V8, no cold air intake or anything but what the factory put in it and I get 23 mpg.. my exhaust was rusted so I took it off up to the catalytic converter and now I get 25mpg, I can go 530 miles on a $100.00

    Reply
    • a different David
      Aug 27 2014

      pardon my french , but no stinking way do i beleive a 1995 K1500 factory set up or not will NOT get 25 mpg, gotta see the video of filling up, drive 25 miles and fill up again and it only hold 1 gallon for me to believe, baby it for the 25 miles down hill and it still wont get 25 mpg, and as far as 100$ lasting 530 miles , are you buying gas for less than everyone else??? at $3.25 per gallon 100$ will get you 30.77 gallons, . 530 miles on 30 gallons is only 17 mpg. definitely more believable but my 2005 factory set up and in town driven only gets 12 mpg here lately. and before you ask yes i do have the tires properly inflated…LOL

      Reply

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