Calling engineer types - exhaust technology

Discussion in 'General' started by HPPT, Apr 14, 2022.

  1. metricdevilmoto

    metricdevilmoto Just forking around

    Mass inerters or J dampers.
    27 likes this.
  2. metricdevilmoto

    metricdevilmoto Just forking around

    How much weight needs to be added?
  3. HPPT

    HPPT !!!

    9 kg.

    p.s. The job is done. I'm just trying to satisfy my own curiosity.
  4. fastfreddie

    fastfreddie Midnight Oil Garage

    Akrapovic and lead weights around the steering stem and swingarm pivot is the answer. ;)
  5. HPPT

    HPPT !!!

    They are part of the problem: their shit is too light. :)
  6. fastfreddie

    fastfreddie Midnight Oil Garage

    And you find fault with that? :confused:
  7. HPPT

    HPPT !!!

    It wasn't a problem until this year when the FIM said to put 9 kg on the bike.
  8. 27

    27 Well-Known Member

    What’s old is new again... my first car... 68 Pontiac Firebird 400 convertible has the fluid filled mass dampers in each corner of the car...

    probably weigh about 50 lbs each, so whatever is in them must be the density of liquid lead or something as the volume looks to be under 2 gal.

    All the F body convertibles had them I think. I wonder what handling characteristic flaw caused them to need those?
  9. 27

    27 Well-Known Member

    Where did they put it? Which bike was it?
  10. cBJr

    cBJr Well-Known Member

    As exhaust gasses cool down inside the exhaust, they become more dense. This creates a greater load the engine has to push out.

    Steel conducts heat greater than titanium, so it cools down more and loses more power.

    Edit: I'm still in the "negligible actual difference" camp, but that's the simple theory I'd go with.
    HPPT likes this.
  11. 27

    27 Well-Known Member

    Hey Mike... any breakthrough on the shock linkage?

    I’m sure not but just checking...
  12. D-Zum

    D-Zum Alex’s Ohvale Maintenance & Transport Service

    I’d be more interested in the whole dyno curve than concerning myself with 1 hp more at peak.

    Does the Ti exhaust affect the overall curve better than stainless?
    fastfreddie likes this.
  13. sharkattack

    sharkattack I didn't choose the Thug Life; it chose me.

    Hell, I gained 5 HP just by adding some go-fast stickers to my bike. I don’t screw around with measly 1 HP gains; I go all in on my quest for more powah!
  14. Mongo

    Mongo Administrator

    Racing stripes on cars and bikes is another 5%
    Steeltoe likes this.
  15. metricdevilmoto

    metricdevilmoto Just forking around

    For most race applications, they are used to cancel a specific resonant frequency on the sprung mass that is inherent to the chassis without changing suspension characteristics.
    27 likes this.
  16. metricdevilmoto

    metricdevilmoto Just forking around

    Nope. Replaced and out there in the wild racing.
    27 likes this.
  17. HPPT

    HPPT !!!

    Frame, around and under the battery.

    Same R6 as first post. :Poke:
    27 likes this.
  18. Trainwreck

    Trainwreck I could give a heck

    You're thinking of Inconel. Indy Car, Formula 1, WRC, and a lot of MAX Effort Hill Climb/Time attack cars use it. Has really good resistance to fatigue cracking from heat, most of the time 0.020" wall or smaller is used (I've heard of NA cars using something wild like 0.010-0.015 or something ) WRC cars are prolly the most abusive to their manifolds, with basically sending massive explosions down the runners to keep the turbo online during off throttle/transient throttle.

    Other than weight savings and structural integrity with heat/vibrations Inconel and Titanium don't really have a whole lot over good stainless. The weight savings being the biggest thing. Some have argued that harmonic frequency stuff and blah blah blah may contribute to the exotic alloys being superior, but you're maybe getting 0.5-1% gains with this and only in certain rpm ranges more than likely.

    The smoothness in the bends comes from the manufacturing process, not the material itself.

    Also, FWIW to those who may be interested... Inconel is the one of the most frustrating things I've ever welded in my whole ass life. With most metals, even Ti, you have a pretty good sense of how well your doing based on how the puddle is moving around and maintaining shape. Inconel is very sluggish and is pretty slow to react to your torch movements.

    Again, it is in my opinion that other than weight and fatigue resilience, there are no "extra" benefits to using exotics over SS. If so, you'd see a hell of a lot more of them in classes where they don't care. especially in stuff like drag racing, and where they'll spend dumb amounts of money to save .5lb. Hell, the turbo radial cars run aluminum down pipes on their 1500-3000hp engines.. lol

    A 1hp difference is more than likely the resolution of the Dynometers repeatability. ESPECIALLY if its a chassis dyno, and not an engine dyno.

    Source: Me... I've built a lot of forced induction and exhaust systems over the years.. everything from import drag cars, V8 stuff, and time attack cars.
    Last edited: Apr 14, 2022
    G 97, 27 and HPPT like this.
  19. G 97

    G 97 Garth

    Yes but does heat create or impose any hindrance of flow to begin with? So even if certain metals can dissipate heat at a higher/quicker level, does it actually increase exhaust flow?
    27 likes this.
  20. G 97

    G 97 Garth

    There would have to be a substantial change in temperature for this to have any significant effect. A change that I wouldn’t think would occur under full load or an engine under racing conditions.
    Last edited: Apr 14, 2022

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