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     These articles were intended to help explain some questions and help educate performance enthusiasts.  My hope is that readers can find something useful and apply this to good use.  Please enjoy these writings. 

Comments
  1. Rick says:

    Man what great articles!

  2. here says:

    I love reading an article that can make people think.
    Also, thanks for allowing for me to comment!

  3. Dave B says:

    I read the article on the twin scroll turbo. My immediate thoughts were as far as design on the exhaust manifold were; for the length do you design for torque or horsepower or settle for an average, second what is the velocity of the gasses to optimize length for cleaner entrance into turbo with reference to both pulses and scavenging and do you also design for these factors at an average? Obviously in extreme competition cases such as sled pulls or 1/4 mile or road racing tuning for peak numbers will always be at the highest values.

    • Thanks Dave. Exhaust design can vary with application. How the engine will be used 90% of its life should dictate the build. So here’s the “I’m sorry to be so vague” answer…exhaust design should be to maximize the efficiency of the chosen turbo for the application. Meaning pipe length and diameter, as you may know, effect the response of the turbo. Now for the second part, since mass airflow is the determining factor of power, air pressure at the inducer of the compressor wheel effect this air mass. To this end, this is why turbo systems set up for track will utilize the vehicles aero to provide pressure at the wheel. Not very conducive for street.

      • Dave B1 says:

        That’s helpful info. I am an engineer tech and use catia so I was playing around with the fea side of it. With the length of the tubes energy is lost if you can either keep the energy from dissipating (not the optimum solution unless you have some sort of ceramic ti turbine) more of it is transfered to the turbine where that energy can be utilized more efficiently. I know a little about thermal dynamics but not enough to really be able to do what I am trying to do which is for optimum conditions have the right length tubes whereby the exhaust gases provide scavenging but not bottle neck which ultimately leads to the logical conclusion that tapered tubes of the correct length provide the optimum need at whatever rpm dependant on end use of course. This is all theory but I’ve been trying to find a little more on the subject to see if my fea studies are close to real world #’s, tanks for your input and help. On Jan 26, 2016 10:50 AM, “performancespecialties” wrote:

        > performancespecialties commented: “Thanks Dave. Exhaust design can vary > with application. How the engine will be used 90% of its life should > dictate the build. So here’s the “I’m sorry to be so vague” > answer…exhaust design should be to maximize the efficiency of the chosen > turbo for t” >

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