flywheel horse and rear wheel

Discussion in 'Mopar Performance Issues' started by Marcohotrod, Dec 29, 2017.

  1. Marcohotrod

    Marcohotrod Well-Known Member

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    there is a lot of horsechit out there about how much is lost to the drivetrain. Can anyone please tell us about actual engines tested on the dyno and then on a chassis dyno. and please add how on the engine dyno it was run with or without air filter, fan, mufflers, alternator, water pump, power steering, etc. thank u
     
  2. mzak88

    mzak88 Well-Known Member

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    mine was done without air cleaner, no alternator. Electric water pump.
     
  3. Pascamp

    Pascamp Well-Known Member

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    What specifically are you looking for. The most accurate comparisons you're going to get are going to be newer vehicles. Factory net ratings are dead nuts, so that's one part of the equation. Then find guys who did baseline runs on chassis dynos, and used the same Dyno after mods. Anything involving gross hp, different dynos, ect would be an apples to oranges comparison.
     
  4. RustyRatRod

    RustyRatRod Just another dumbass. FABO Gold Member Technical Editor

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    Not bein a smartass so please don't take it that way.......but why does it matter? I mean, if you actually had much control over it, that would be one thing. You are limited however, to what type transmission and drive line you use. That's pretty much it. In other words, you're kinda stuck with what ya got.
     
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    • fishmens67

      fishmens67 Well-Known Member

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      yea a lot of horse dung for sure. most of the 500 -550 Hp 408 strokers must lose 150 through the drivetrain because 1/4 mile mph #'s say so. lol a lot of happy dyno's out there.
       
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      • Demonic

        Demonic Well-Known Member

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        Even if you did a comparison, a dyno is just a gauge. So if you ran your engine in a dyno then ran the car with installed engine on a chassis dyno, they're still different gauges. You'll get a rough idea of the chassis loss, but one could be happy, different weather, etc, etc.
         
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        • BrianT

          BrianT Let's go! FABO Gold Member

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          I have the info you're looking for but like was said before there's so many variables that you can't do a real comparison.

          My 408 made 497hp/519tq on an engine dyno with no air cleaner, mufflers or accessories. The same engine in my car with air cleaner, exhaust with mufflers but no tail pipes and an alternator made 407hp/407tq. That's with a 727 and a Dana 60 rear end. That's 18 percent parasitic loss and about what we were expecting. Hope this helps.
           
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          • TF360

            TF360 Well-Known Member

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            Here's kind of a cool comparison. In 1971 the 225 slant six was rated at 145 hp. Then in 72 when they changed the way they rated the HP (net) it went to 110. Same set up.
             
          • Marcohotrod

            Marcohotrod Well-Known Member

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            Thanks BrianT-that is what I am looking for. I am curious to learn and cut through the crap that some "experts" spout about how much less power is made on a chassis dyno compared to an engine dyno. like "chassis is 25% less than flywheel". I know it is not that simple. depends on tranny and rear endand fluids used and more. and I don't like engine dyno testing done for the big bragging number-no air filter, no mufflers, etc. I have not dyno tested my chit, I do it at the Epping 1/4 mile
             
          • 68dodge

            68dodge Well-Known Member

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            Just for more more info. I lost about 100 HP between the motor and chassis dyno. Motor dyno no air cleaner, electrical water pump, headers. Car has all electric pumps, electric fans and alternator.
             
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            • moper

              moper FABO Gold Member FABO Gold Member

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              That will be hard because the dynos are all individually calibrated. When I was involved in a chassis dyno shop we used 18% for automatic, 15% for manual cars. IN most cases this was backed up by owner provided info but you never knew if the engine dyno was happy or sad... The places using higher figures may believe they are right, and the engine dyno being compared to is off - any they may be right, or full of crap... I tend to think chassis dynos when calibrated right are more "real", because they include all the power limiting factors that engine dynos don't. The intent of engine dynos is usually to safely break in a new engine, and provide a number for the owner or bragging rights for the shop or owner.
              That's why the informed enthusiast will say it's a tool and the numbers are guides only, not gospel.
               
            • yellow rose

              yellow rose Doctor of Thinkology.

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              Same numbers I used. Although some of the later stuff with 6 speed autos and such eat a bit more than 18%. So we went 20% on that stuff.
               
            • 440dartsport

              440dartsport Well-Known Member

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              I’ve dynoed a few combos. The first one was a 500” stroker that made 763hp at the flywheel And 579hp at the wheels. That was through a 4 speed and Dana 60. The second combo was a 572 in the same car that made 943hp at the flywheel and 640 at the wheel through a TH400 and 5500 stall converter. There was no alternator on the engine Dyno tests but we did back to back tests and the alternator only lost a few hp. There was also exhaust on the car on both chassis Dyno’s.
               
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              • IQ52

                IQ52 Well-Known Member

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                694 HP engine dyno, 554 RWHP
                848 HP engine dyno, 696 RWHP
                Both running 833 4-spds
                 
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                • famous bob

                  famous bob mopar misfit

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                  Methinks that`s too much !!
                   
                • famous bob

                  famous bob mopar misfit

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                  DAM ! I REGRESS !