• Nov 23rd 2011 at 6:01PM
  • 20
Unless you happen to own a dyno, accurately keeping track of which modifications benefit your vehicle may be a seat-of-the-pants operation. AEM is hoping to change that for people who are serious about wringing the absolute most out of their vehicle with the unfortunately-named Dyno-Shaft.

While the product may sound like a bizarre fetish film, it has the potential to revolutionize tuning for those of us who don't have access to high-dollar engine evaluation equipment. The Dyno-Shaft uses grade-strain gauges to measure horsepower and torque at transmission output shaft, so AEM maintains that the system's readings aren't impacted by variables that typically skew accelerometer readings.

AEM says that the the data broadcast device for the system is non-contact, doesn't use slip rings and needs no batteries, all of which are good things. Buyers simply install the supplied slip-yoke as well as a drive-shaft speed sensor and get going. Data is transmitted via a CAN-bus communications network to a data logger or an AEM engine management system. Prices start at $1,160.96 for cast-iron slip yolk applications, and AEM says that each Dyno-Shaft is specifically calibrated for your application. Chrome moly yolks are also available for higher-horsepower applications. We desperately want to play with one of these to see how accurate it is compared to a traditional full dyno setup.

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    • 1 Second Ago
      • 3 Years Ago
      For a company that caters primarily to the FWD car crowd, it seems odd that they'd introduce a product that can't be used on one.
      Ralph Waldo Emerson
      • 3 Years Ago
      So Autoblog wants to "play with" a dyno-shaft.... Tehehe! :)
      • 3 Years Ago
      Slip yolk??? Slip YOKE!!! Yolk: the yellow and principal substance of an egg, as distinguished from the white. Yoke: a part, especially one of relatively thick cross section, that secures two or more components so that they move together. Come on autoblog, this is an automotive site, I expect more from you!!
      • 3 Years Ago
      "We desperately want to play with one of these to see how accurate it is compared to a traditional full dyno setup." This statement gave me pause as it seems even between "traditional full dyno setups" you will get substantially different numbers. I guess the bar is set low.
      • 3 Years Ago
      I remember seeing these at SEMA. I'm a bit skeptical at the accuracy of the product, and definitely not looking forward to those folks who love to throw figures at you getting their hands on these (seriously, unless I ask, I don't care what your car is putting out). That said, while I'm sure many tuners will stick to their to-the-wheels dyno machines, this is a very elegant idea for those who want to tune but are out of range for using a dyno.
      Philip Gray
      • 3 Years Ago
      Yeah, nothing can go wrong here!
      • 3 Years Ago
      Its seems cool if its acturate but $1,160 is a lot of dyno runs.
      • 3 Years Ago
      Sounds good on paper... I used to be really into tuner cars, would have loved this at the time.
      • 3 Years Ago
      Sorry if I'm not perverted, autoblog, but it didn't seem unfortunately named for me until you pointed it out. With that said, this little thing seems pretty cool if it actually works well!
      • 3 Years Ago
        • 3 Years Ago
        I wouldn't right out call it a waste of money depending on two things - 1. This thing actually works and isn't a source of instant high RPM death and 2. The project / engine in question has a carb or aftermarket EFI which can be reprogrammed / retaught after each mod. If those are true, then this is a GREAT gift to builders everywhere!
          • 3 Years Ago
          I'd imagine this being mainly for project cars. It'd be complete overkill to use one to see how much HP/TQ your corvette is putting down if you just threw a hot cam and a reflash on it. Also, that disclaimer is fairly standard for aftermarket parts. It just means they can't be held liable if you install it wrong and damage something, or if incorrect installation leads to a failure that causes injury.
        • 3 Years Ago
        The software HP/Torque calculations are derived from the BSFC and calculated fuel flow, and those are derived from the measured air flow. Provided your BSFC numbers are dead accurate, and all your various injector and MAF/VE Table settings are perfect, it'll get you a number that's within the ballpark, but can still be off by quite a bit.
      Devin Christiansen
      • 3 Years Ago
      Time to grab my cement blocks and jack.
      Godless Commie
      • 3 Years Ago
      Zach Bowman does not know the difference between a "yoke" and a "yolk". Lulz.
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