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    • Mustang versus Dynojet dyno results courtesy of a VAC Motorsports built E92 M3 S65 V8

      All dynos are not created equal. One 'rule of thumb' so to speak on automotive forums is that the Mustang dyno reads lower than the Dynojet. In most cases, that is absolutely true. Take this E92 M3 modified by VAC Motorsports for instance. The car has an Active Autowerke tune, Fabspeed cat bypass, Fabspeed X-pipe, and Fabspeed mufflers. What does it put out on VAC's Mutang Dyno? 334 horsepower to the wheels. And on a Dynojet? 390 wheel horsepower in STD correction.


      That's a spread of 56 wheel horsepower for the same car with the same mods, significant. Just changing the correction on the Dynojet to SAE changes the numbers to 378 horsepower to the wheel. 12 horses less than in STD correction on the same dynojet and 44 horsepower more than on the Mustang dyno. The next time one is comparing dyno results remember that the numbers can very based on the dyno, conditions, and correction and the same car and show very different numbers due to this.

      Additionally, the Mustang Dyno does not always read low. This is commonly cited but AMS showed recently how Mustang numbers can be manipulated rather easily. Dyno numbers are just part of a picture but more often than not used for bragging rights. One thing is certain, it's easier to skew dyno numbers than a timeslip.

      Power mods:
      Active Autowerke Software
      Fabspeed primary catbypass
      Fabspeed non-resonated x-pipe
      Fabspeed MaxFlo mufflers

      VAC Mustang:
      334hp 247tq

      Dynojet SAE:
      378hp 272tq

      Dynojet STD:
      390hp 280tq






      This article was originally published in forum thread: S65 n/a Dyno Results - Mustang vs. Dynojet started by Mike@VAC View original post
      Comments 24 Comments
      1. benzy89's Avatar
        benzy89 -
        Just more evidence supporting the fact that you should try to always get numbers from the same dyno & focus on the gains made. Sick of people saying "your numbers are no good because they're not off a DynoJet".

        Mike -- Now that you guys have put out more info on the VAC S65 stroker builds, is this customer looking into it? Def seems more appropriate building a stroker than bolting on a s/c for a dedicated track car.
      1. inlineS54B32's Avatar
        inlineS54B32 -
        I think mustang dynos are garbage for this very reason. A horsepower is a horsepower is a horsepower... The company should be removed from this earth. Oh, lets calculate a horsepower differently and start a dynamometer company.

        I am kidding of course, but not kidding at the same time. For the reason they read low I have posted about, but because of that they suck for 99% of the cases.
      1. BrenM3's Avatar
        BrenM3 -
        ^ Not sure you understand the difference of load-based versus interia based dynos and how they calculate horsepower.

        For tuning a vehicle a Mustang dyno or load cell based system (Mainline, Maha, Dyno Dynamics, Dynapack) will allow the tuner to do much much more. It is the preferred machine for MANY successful companies. I love when people try to do steady-state or from scratch standalone tuning on a older dynojet dyno and then the car drives like total garbage on the street. The newer load cell based dynojets still don't do everything the Mustang can do either.
      1. Mike@VAC's Avatar
        Mike@VAC -
        We own a Dynapack (the golden standard) and Mustang AWD. Load based is preferable for tuning.
      1. BrenM3's Avatar
        BrenM3 -
        You own the tool best tuning tools out there my friends Click here to enlarge^
      1. MisterEm's Avatar
        MisterEm -
        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        I think mustang dynos are garbage for this very reason. .
        I respectfully disagree. Although the mustang dynos do not produce the hero dyno sheets we all want our Mom's to place proudly on the fridge - the Mustang dyno cannot be beat for tuning (partial load especially) and driveability.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by benzy89 Click here to enlarge
        Just more evidence supporting the fact that you should try to always get numbers from the same dyno & focus on the gains made. Sick of people saying "your numbers are no good because they're not off a DynoJet".

        Mike -- Now that you guys have put out more info on the VAC S65 stroker builds, is this customer looking into it? Def seems more appropriate building a stroker than bolting on a s/c for a dedicated track car.
        It's just that a dynojet has the largest base of reference so it's most convenient if you want to the paper comparison.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BrenM3 Click here to enlarge
        ^ Not sure you understand the difference of load-based versus interia based dynos and how they calculate horsepower.

        For tuning a vehicle a Mustang dyno or load cell based system (Mainline, Maha, Dyno Dynamics, Dynapack) will allow the tuner to do much much more. It is the preferred machine for MANY successful companies. I love when people try to do steady-state or from scratch standalone tuning on a older dynojet dyno and then the car drives like total garbage on the street. The newer load cell based dynojets still don't do everything the Mustang can do either.
        But the numbers are higher Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by MisterEm Click here to enlarge
        I respectfully disagree. Although the mustang dynos do not produce the hero dyno sheets we all want our Mom's to place proudly on the fridge - the Mustang dyno cannot be beat for tuning (partial load especially) and driveability.
        Tuners love them but from what I understand the highest quality load based dyno for tuning is the dyno dynamics due to the options. The tuners should be able to shed more light.
      1. inlineS54B32's Avatar
        inlineS54B32 -
        Click here to enlarge Originally Posted by BrenM3 Click here to enlarge
        ^ Not sure you understand the difference of load-based versus interia based dynos and how they calculate horsepower.

        For tuning a vehicle a Mustang dyno or load cell based system (Mainline, Maha, Dyno Dynamics, Dynapack) will allow the tuner to do much much more. It is the preferred machine for MANY successful companies. I love when people try to do steady-state or from scratch standalone tuning on a older dynojet dyno and then the car drives like total garbage on the street. The newer load cell based dynojets still don't do everything the Mustang can do either.

        I understand completely. However, they shouldn't call their rating a horsepower if it's not one is all I mean. From a purely mathematical/physics perspective, this shouldn't differ from machine to machine in a perfect world. That's all I mean. I understand fully the diferences - I have posted about this before... It makes things very confusing when you cannot say - my car makes X HP when it means nothing unless you quantify X with "on this dyno at this location". Again, a perfect world. Just because a mustang dyno is using eddy currents and one uses a fixed mass drum doesn't make the definition of a HP any different.

        However, I completely get your point - they may be more helpful than another dyno when looking at how the car will react in the real world. I am just talking about SAE rated HP though - I feel this shouldn't change...
      1. BrenM3's Avatar
        BrenM3 -
        Read the story of how the dynojet rating of HP was started back when they were created and you will see how drastically unscientific it was.

        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        I understand completely. However, they shouldn't call their rating a horsepower if it's not one is all I mean. From a purely mathematical/physics perspective, this shouldn't differ from machine to machine in a perfect world. That's all I mean. I understand fully the diferences - I have posted about this before... It makes things very confusing when you cannot say - my car makes X HP when it means nothing unless you quantify X with "on this dyno at this location". Again, a perfect world. Just because a mustang dyno is using eddy currents and one uses a fixed mass drum doesn't make the definition of a HP any different.

        However, I completely get your point - they may be more helpful than another dyno when looking at how the car will react in the real world. I am just talking about SAE rated HP though - I feel this shouldn't change...
      1. BrenM3's Avatar
        BrenM3 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Tuners love them but from what I understand the highest quality load based dyno for tuning is the dyno dynamics due to the options. The tuners should be able to shed more light.
        My experience is the opposite, while a quality machine I found significant variation from day to day (same stock car going up or down 30hp with no changes) with a Dynamics. I didn't install it or setup the config file in all fairness though. I find Mustangs amazing though. It will be our next purchase.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BrenM3 Click here to enlarge
        Read the story of how the dynojet rating of HP was started back when they were created and you will see how drastically unscientific it was.
        Yep and the 15% drivetrain loss number was essentially just created by them.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by BrenM3 Click here to enlarge
        My experience is the opposite, while a quality machine I found significant variation from day to day (same stock car going up or down 30hp with no changes) with a Dynamics. I didn't install it or setup the config file in all fairness though. I find Mustangs amazing though. It will be our next purchase.
        You prefer the Mustang to the Dynapack?
      1. z3speed4me's Avatar
        z3speed4me -
        Who cares about HP; show me a trap speed, that's all I care about.
      1. BrenM3's Avatar
        BrenM3 -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        You prefer the Mustang to the Dynapack?
        They both can do things the others can't but as far as WOT tuning, I like the Dynapack the best. Ideally both can be used depending on the application.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by z3speed4me Click here to enlarge
        Who cares about HP; show me a trap speed, that's all I care about.
        I'd like to know what my WHP is for my trap speed. I like to have both not one or the other .
      1. maxnix's Avatar
        maxnix -
        Click here to enlarge Originally Posted by inlineS54B32 Click here to enlarge
        A horsepower is a horsepower is a horsepower...

        For the reason they read low I have posted about, but because of that they suck for 99% of the cases.
        Actually, HP is a calculated number at a particular RPM based on the torque at that RPM.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by maxnix Click here to enlarge
        Actually, HP is a calculated number at a particular RPM based on the torque at that RPM.
        He knows that and wasn't saying differently...
      1. inlineS54B32's Avatar
        inlineS54B32 -
        Click here to enlarge Originally Posted by maxnix Click here to enlarge
        Actually, HP is a calculated number at a particular RPM based on the torque at that RPM.
        ? What?

        Did I say something otherwise?

        Edit - didn't see above post