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  1. #1
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    Default Exhaust sizing help

    While I'm off for college I'm looking to have exhaust work done to my truck. I was thinking one pipe back from the y pipe into a muffler and out two straight out the back. What would be the better deal?
    Prices I found were:
    Custom 1: $400 choice of muffler,tips, and 3" pipes
    Custom 2: $350 (ish) choice of muffler,tips, and 3.5" or 4" if wanted 3" like I want he will have to order new tips.
    Kit: From Truck exhaust kits.com; $260 choice of muffler, tips, 2.5" (would weld together)

    I read on a previous post that someone recommended 2.5" for dual exhaust. Could someone explain why you would want to go from a stock 2.75" to dual 2.5"
    Objects in mirror are losing

    2003 Chevy Silverado Z71, 5.3L, K&N 57 series, 2.5'' Flowmaster Super 10 series dual exhaust , Corvette Servo, McNew Automotive Dyno tune, SS gauge cluster, Extang Trifecta Tonneau, Pacesetter shorty headers, Goodmark cowl hood, Sony Xplod speakers, Kenwood DDX-470 exhaust tips, 16" Ultra Badlands polished wheels, Pirelli Scorpion ATR .

  2. #2
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    Default

    Anybody with any help or thought?

  3. #3
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    Kyle, I have side exhaust so I didn't have .02 cents to reply to full length exhaust, but I like the Gibsons you were telling the newbie about on the other thread. Less weight, & no turning your bumper blue with exh residue
    1988 Chevy C-3500 2wd (no pic)
    350 c.i. 5.7 L Stock Block, 4 Bolt Mains
    L-31 Vortec Heads, Edelbrock Cam & Intake,
    Holley 650, Flowtech Headers, Magnaflow exh.
    Jet Trans 700R4, B&M Ratchet, 4:10 gears,
    3" susp. lift kit "shadetree"
    No rev limiter, No speed limiter lol


  4. #4

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    Each time I've had custom true duals put on my trucks I've always ran 2.5'' inch pipe. If you go bigger than 3'' on a gas your gonna slowly lose performance and sound. You need to have a little back pressure. The dual exhaust allows for more airflow so if you go with slightly smaller pipe it will balance out. Just my $.02 from experience!

    2006 Duramax LBZ
    Edge Evo
    4'' Diamond eye to 6'' tip
    16'' ion alloy, 33'' fierce attitudes
    Lots of work left to do!

  5. #5
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    Ok guys well thanks! I always heard bigger was better but too big is bad but thanks guys, I mean it.

  6. #6

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    Yeah its pretty much true most of the time! I was never a big believer in back pressure because why would restricting airflow make an engine run better? So one day I took my muffler off my R6 out of curiosity and it sounded good! So I left it off till one day when I put it back on. When i went to ride it I had a whole lot more power! That difference was crazy! I'm sure with a new tune for the mufflerless exhaust would help it out but I was still surprised!

  7. #7
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    Wow never would have thought. Im still thinking about this kit. $270
    http://www.truckexhaustkits.com/prod...haust-Kit.html

  8. #8
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    Quote Originally Posted by ntbush83 View Post
    Yeah its pretty much true most of the time! I was never a big believer in back pressure because why would restricting airflow make an engine run better? So one day I took my muffler off my R6 out of curiosity and it sounded good! So I left it off till one day when I put it back on. When i went to ride it I had a whole lot more power! That difference was crazy! I'm sure with a new tune for the mufflerless exhaust would help it out but I was still surprised!
    You're right Nathan, but what never gets explained clearly is what is actually happening, with or without the backpressure. People always say you "need some backpressure" but they don't explain why, cuz they don't understand it.
    The faster or slower the exhaust flows, just moves the torque/HP up or down in the RPM range. Most of us drive in the lower RPM ranges so having mufflers on (& more back pressure) gives us more torque in the lower RPM range where we feel it all the time. Guys who drive in the upper RPM range more often, do better without mufflers cuz they want the torque/hp up there.

  9. #9
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    Ok so you all think 2.5" is the best size all around for the exhaust im talking about.

  10. #10

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    Yes 2.5" will be plenty for your truck and even if you do get a cams/heads/intake also. My 79 TA had a 400 big block Pontiac and I ran shorties (for clearance with a man tran), true dual 2.5" pipe with forceaflow 2 chamber mufflers. The car sounded/ran great. Those knock off flowmasters are good quaiity and sound just as good!

    2000 GMC Sierra 1500 Z71
    Stock 5.3L
    High Flow Filter
    Dual Exhaust
    KC Driving Lights behind Grille
    2011 17" GMC takeoffs
    Nerf Bars
    Toolbox

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