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Single or Duel Exhaust ??

Discussion in 'The Garage' started by Z3PR, Jul 24, 2003.

  1. Z3PR

    Z3PR Banned

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    I've always went with duel exhaust, Just like it better, can't say why, just do. ( I Plan on Thorley Tri-Y's into 2.5" pipes with 40 series Flowmasters, and dumping the exhaust infront of the rear tires "Duel Exhaust" ) What do you run, and why ???
     
  2. TruckNutzDude

    TruckNutzDude 1/2 ton status

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    I'll be running a Flowmaster 3" cat-back system. Single exit in stock location w/ a 50 series muffler. I'm going with this kit because I don't like to go deaf when I'm driving on the highway (which is what happens w/ 40 series) and because it's the only bolt on kit flomaster makes for my blazer (p/n 17161) /forums/images/graemlins/grin.gif As you know flomaster's are the most crush proof mufflers out there and add the most torque, in my opinion, but you knew that already! /forums/images/graemlins/ignore.gif
     
  3. fortcollinsram

    fortcollinsram 1/2 ton status

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    Thorley headers, dual 3" with Flowmaster 50's....Why? BECAUSE IT WAS FREE (except for the headers /forums/images/graemlins/tongue.gif)

    Well that is what I will have by the end of this weekend...

    Now I have Thorley Tri-Y's with dual 2-1/4", that is b/c It was on my trucl when I bought it (again except for the thorleys)

    Personally with a SBC, I like a single 3"...With BBC, Dual 2-1/2" to 3"

    Just my personal favorite...

    Chris
     
  4. Twiz

    Twiz 1/2 ton status

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    Exhaust

    Exhaust isn't simply "expelling used A/F". It's part of a system. From the wing nut on the air cleaner to the tip of the tail pipe, it's a system.

    All too often, the power from a well devoloped exhaust system isn't realized to it's full potential. Ofcource, the more radical the power plant, the more important the exhaust system becomes. But, even a mild engine can benifit from a well enginered exhaust system.

    1 - (Free-flowing exhaust) - Up to 50% of the power "re-consumed" by the engine, is due to exhaust pumping losses (the piston haveing to push exhaust gasses out of the engine). This also, consums fuel, which will effect the milage.
    * This doesn't mean that a 150 hp engine is actualy a 300 hp engine, less the pumping losses.*

    2 - (Pressure Wave Tuneing) - A tuned exhaust system can create a much higher pressure difference (IE, vacume) during valve over-lap, than the downward traveling piston during the intake stroke (!).


    In extream, WOT (Wide Open Throttle) raceing applications, it's fairly easy. Buy a set of "race headers" (useualy, too big, and too short), adjust the collector length ("old-schoolers", would draw a line down the colletor extension, and cut it where the line melted off.)

    For "us" as PT (Part Throttle) enthusiasts, we have it a bit more diffacult. Engine power out-put will be controlled by the throttle. Makeing praticaly any modification relitivly, useless. That doesn't mean, we can't be rewarded with increased fuel economy and power by modifing the exhaust system - it simply means that our intended goal differes from what is typlicaly avalible from After Market suppliers.


    More to follow........
     
  5. Twiz

    Twiz 1/2 ton status

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    [ QUOTE ]
    1 - Free-flowing exhaust

    [/ QUOTE ]
     
  6. Twiz

    Twiz 1/2 ton status

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    [ QUOTE ]
    2 - Pressure Wave Tuneing

    [/ QUOTE ]
     
  7. rigdonhome

    rigdonhome 1/2 ton status

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    In GENERAL:

    True duals will sound nicer than a single pipe or duals with a crossover.

    The longer the exhaust is and the more bends it has, the nicer it will sound. (Big Block Caddy with about 50' of 2.5" pipes coming all the way out the back was the sweetest sounding exhaust system I've ever had!!!)

    For performance, a single exhaust system that flows the same amount of exhaust volume will perform better, but not sound as good. It will have more of a deep rumble like a lumber truck. Just depends on what you consider 'sounds nice'...

    If you do the math (and no it's not this simple but for street apps it is close enough...) a single 3" pipe will flow more exhaust than two 2" pipes. Two 2.25" pipes flow slightly more than a single 3" pipe. (Just going by cross-sectional area, although a single pipe has less surface friction (perimeter) than dual pipes...)

    Also realize that the exhaust cools (and therefore takes up less volume) as it gets farther from the engine, so you could easily have smaller pipe behind the mufflers without causing much of a restriction.

    I currently have:
    1978 Malibu with mild 350, 1-5/8" primary headers into 3" collectors, then 2.5" duals all the way out the back. Rumbles like a truck, but is about as 'freeflowing' as anything I've ever had. This car is much more 'Go' than 'Show' so I built the exhaust for function rather than sound.

    1977 K5 Blazer. Mild 350 with stock exhaust manifolds and 2.25" duals. Sounds awesome but is a little loud to ride in as a daily driver.

    1992 G20 Conversion Van. Stock TBI 350 with 2.25" downpipes that Y into a 3" single pipe, all the way back to a 3" inlet Flowmaster with two 2" outlets. It has a meaty rumble at idle, is quiet at part-throttle, but sounds like true duals when you give it hell. Probably my favorite of all my exhaust systems right now.

    1995 LT1 Z28. 'Stock' exhaust is either 3" or 3.5" single pipe all the way back to a muffler that splits into two 2" pipes. It must flow good from the factory because the Cat-Back aftermarket systems only get you like 15hp... This is the nicest sounding 'factory' exhaust system I've ever heard. It doesn't really sound like true duals to me, but it has a nice meaty rumble when you get on it, but is quiet enough to drive daily without having to shout at your passenger.

    Overall I'd say true duals with a crossover or 'H' pipe in between them is the best compromise between sound and performance. The 'H' pipe will quiet the system down a little, but you'll still basically have the sound of duals.

    I think I just gave like 5 different opinions. Hope that helps to confuse the issue.

    Sal
     
  8. gravdigr

    gravdigr 1/2 ton status

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    I thought the H pipe also equalized pressure between the pipes which affected performance somehow...

    I will be running a slightly modified 350 sbc with hooker headers, 1 5/8" primaries 3" collector dumping into dual 2.5" pipes with a crossover. Why am I doing this? Just because. It is far more difficult than running a stock setup. If we ever get emissions testing here I'd be screwed. But headers and duals are cool. I like the sound and I like the image. No one is impressed by a single exhaust, or by a fake dual exhaust (Y pipe after the muffler). But people love headers and true duals.
     

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