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better mpg?

This is a discussion on better mpg? within the Exhaust forums, part of the Performance category; im thinking of getting dual exhaust. has anyone noticed better mpg wth duals versus stock or single?...

  1. #1
    Registered User chevy2thelevee's Avatar
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    better mpg?


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    im thinking of getting dual exhaust. has anyone noticed better mpg wth duals versus stock or single?
    In order to be cummin you have to be strokin', in order to be strokin, you have to be Like A Rock

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    big blazen bigk20chevy's Avatar
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    Re: better mpg?

    i noticed a little but not much maybe 1-2 mpg with a full exhuast headers everything
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    Registered User hicksjordan92's Avatar
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    Re: better mpg?

    Sometimes u can lose power and performance with the exhaust cause on the newer trucks backpressure is very important to to make the truck run correctly but as far as gas milage it probabely wouldnt change it enough to matter.

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    Registered User SierraDan's Avatar
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    Re: better mpg?

    Just make sure to keep the pies sized correctly, large enough to flow well but small enough to keep velocity up. By your avatar pic (guessing that's yours) i'd guess it's a 5.3 in which case I would go 2.25" to 2.5" duals, no larger. Until you get to 400hp or more, 3" duals aren't necessary. You also can retain mileage and power with a 3" single exhaust, nothing wrong with that. I like the look of duals but I don't think true duals are needed on a pickup that's not going racing so i'm a fan of 3" single splitting to 2.5" duals, that's what my truck has and I love it, cheaper and easier to do that true duals. I may go true duals when I rebuild the motor and use headers because they do sound different than single but maybe not.

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    Registered User chevy2thelevee's Avatar
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    Re: better mpg?

    your close its a 4.8. i was thinking of doing 2.5 pipes with a magnaflow turned out 90 degrees

    Quote Originally Posted by SierraDan View Post
    Just make sure to keep the pies sized correctly, large enough to flow well but small enough to keep velocity up. By your avatar pic (guessing that's yours) i'd guess it's a 5.3 in which case I would go 2.25" to 2.5" duals, no larger. Until you get to 400hp or more, 3" duals aren't necessary. You also can retain mileage and power with a 3" single exhaust, nothing wrong with that. I like the look of duals but I don't think true duals are needed on a pickup that's not going racing so i'm a fan of 3" single splitting to 2.5" duals, that's what my truck has and I love it, cheaper and easier to do that true duals. I may go true duals when I rebuild the motor and use headers because they do sound different than single but maybe not.
    In order to be cummin you have to be strokin', in order to be strokin, you have to be Like A Rock

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    Registered User Low97tahoE's Avatar
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    Re: better mpg?

    i don't know how loud you want it, but i would definately suggest a 14" case round magnaflow....my cousin has it on a 5.3, and its fairly mellow at idle, but when u step on it, it sounds like it's saying don't **** with me, magnaflow on a LS based motor is definately the way to go....now if you get headers you'll probably want the 18" 4x9 oval case magnaflow, cuz the headers make that round case real raspy...but thats just my .02

    well since i just realized ur going with duals, i would get a 3 in single in 2.5" dual out 14" 4x9 oval case
    Last edited by Low97tahoE; 05-05-2010 at 08:59 PM.
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    8 year olds dude ChevyPanther72's Avatar
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    Re: better mpg?

    i got a si/do with 24in glasspack, i like it alot. its not loud enough for my likeing but its good for now. if you dont want it to be to loud then i would do that.

    oh and as for mpg, i did get about a 1-1.5 increase
    Last edited by ChevyPanther72; 05-06-2010 at 07:13 AM.
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    Registered User Midwest Militia's Avatar
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    Re: better mpg?

    If you do duals you may get alittle better gas mileage but nothing super...but your torque might go down hill...I had a SI/DO Flowmaster with 2.5 piping and got like 1-1.5 mph better but my torque suffered. I pulled that apart and went with a 3" glasspack and 3" straight piping all the way back and now I get about the same mph but I have alot better torque.


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