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Anyone Have True Dual Exhaust?

Discussion in '2nd Gen. Tacomas (2005-2015)' started by smd762, Apr 10, 2012.

  1. Apr 10, 2012 at 7:38 PM
    #1
    smd762

    smd762 [OP] Member

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    I'm sure this had been discussed before but does anyone have a true dual exhaust on their 2005-2010 Access Cab 4.0?
     
  2. Apr 10, 2012 at 9:34 PM
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    badger

    badger Well-Known Member

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    By true duals do you mean separate all the way back? Not a good idea. If you did run two pipes you would need a balance pipe between them and the placement of that pipe would have to be at the right location to tune for the exhaust pulses. The 4.0 doesn't have anywhere near the displacement to require dual pipes anyway. Most any attempt to build such a system would end up hurting performance. That's why people like URD who know what they are doing, and have the resources, run a Y pipe and single exhaust.

    You could always run an extra dummy pipe out the back if you really like that muscle car look :D
     
  3. Apr 11, 2012 at 7:50 AM
    #3
    smd762

    smd762 [OP] Member

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    Nah no dummy pipe for me. I was just wondering why there aren't any dual exhaust being sold for the truck, and that answers it. Thank I appreciate it. I'll be looking for a new exhaust soon and it won't be true dual now lol
     
  4. Apr 11, 2012 at 7:54 AM
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    jprovence

    jprovence Well-Known Member

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    It would hurt torque down low, but you would get more higher end power.
     
  5. May 22, 2012 at 8:21 PM
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    BlueTaco07

    BlueTaco07 Super Mod!

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    Im true dualing mine this weekend.
     
  6. May 22, 2012 at 9:23 PM
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    badger

    badger Well-Known Member

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    Even the URD single pipe loses a little low end torque and gains it back higher up. That's pretty good because most "high performance" exhausts lose it low and never do gain anything back. Going straight duals in a driveway retrofit isn't going to gain anything anywhere. It's a total loss. The tiny gains posted by even the URD would never be felt unless you are racing, where every 1/100th second counts.
     
  7. May 23, 2012 at 6:44 AM
    #7
    Lurkin

    Lurkin Well-Known Member

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    Not totally true, without some qualifiers. A true dual system with the proper pipe size and an X/H pipe will retain the exhaust gas velocity and shared pulses that will minimize low rpm scavenging and improve the high rpm breathing some. It all depends on the pipe size though and where you want to optimize your power range. Pipe routing also becomes a big issue (equal length pipes, cats, resonators, mufflers), normally why a good single works out better although even a good single will only gain a few HP way up top.
     
  8. May 23, 2012 at 6:55 AM
    #8
    Lurkin

    Lurkin Well-Known Member

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    Ahh, very true, and I wouldn't do it to mine, but blanket statements when it's not understood what someone is trying to do just perpetuates lotso myths. There are gains to be had, but whether they are worth it or not is totally up to the "someone" doing them. I'm just trying to pass on the facts and let 'em decide if it's worth it to them.

    FYI, I've tried a custom air intake and an AFE, along with a TRD exhaust. I'm now back to the stock intake, with an AFE drop in and the stock exhaust. Kind of like style, very personally subjective.
     
  9. May 23, 2012 at 8:42 AM
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    badger

    badger Well-Known Member

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    Myths? The "true dual system" he is talking about is two separate pipes. With the H pipe you can tune for the exhaust pulses, yes, but the exact placement and configuration of that pipe as well as the pipe sizes are critical to doing that. It would require extensive dyno work to develop. Then you still have the fact that we are talking about a 4 liter engine. The tuned dual exhausts work well with big V8s because they develop almost twice the exhaust volume. Even assuming you could avoid all the pitfalls, you wouldn't gain anything over a good single system unless (maybe) you are building a dedicated drag racer that runs at nothing but full throttle.

    The problem is that everything with the exhaust that increases flow at high RPM also reduces scavenging at low RPM. The reduced scavenging hurts cylinder evacuation, and so low end power suffers.
     
  10. May 23, 2012 at 9:00 AM
    #10
    Lurkin

    Lurkin Well-Known Member

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    Fully agree with everything you've said. Like I said above, I would not consider doing this myself as all mods are trade-offs. "What are you trying to optimize for?" is the question that has to be answered first.

    The myth part is that there are no gains to be had. There are gains, but is it worth it? Totally depends on what you are trying to do with the truck and the $$$ you want to spend. Since the OP didn't state whether he was wanting to optimize as a daily driver or as a racer-boy, you can't assume that this is not something he wants to pursue.
     
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