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The Driveshaft Dyno:
The Tuner’s New Best Friend?

November 5, 2011 by Matt

AEM Dyno-Shaft Dynoshaft Driveshaft Dyno Yoke Slip Ring SEMA

As noted on the Edmunds Best New Product overview of the annual Specialty Equipment Market Association (SEMA) show, among a host of other tuner-related websites, one of the coolest and longest-overdue innovations on display was the AEM Dyno-Shaft on-car dynamometer.

A two-part device basically consisting of sensors installed at opposite ends of a RWD car’s driveshaft, the Dyno-Shaft measures driveshaft load to accurately determine engine horsepower and torque in any given situation. In contrast to the “ideal laboratory” environment of a conventional, external dynamometer, AEM’s product can calculate real world power output during highway pulls, dragstrip launches—anywhere. It stands to really allow the tuner to optimize his vehicle for the entire operational envelope. The Dyno-Shaft won’t work for FWD or AWD cars, isn’t cheap—around a grand—and requires some custom fabrication to fit, but anyone who’s worked out the kinks of an engine swap or massive upgrade will tell you dyno time adds up quickly, and can be only marginally profitable if all your ducks aren’t in a row before you roll onto the rig. If I had a build I was really serious about, I’d strongly consider it.

Filed under: Miscellaneous, News, Technical, Tinkering


  1. John D says:

    That looks like it would be a good alternative for a small shop that can’t afford to purchase a rolling dyno. Hooking it up could be a bit of labor, but I’m sure some enterprising soul could come up with an economical way to do so for a wide variety of cars… If they could make it work it sure would pay for itself in a hurry.

    • Matt says:

      If it had been available at the time, would you have considered it for your ’69?

      As I understand it, it requires a custom driveshaft and has to be basically built into the car, so I don’t think it’s the sort of thing a shop could just have on hand and switch from car to car. I could be misunderstanding that part, though.

  2. John D says:

    If I were going to constantly be tuning/fiddling with a car on a continual basis (or plan on having multiple projects over the years) it may make sense. But I’m the kind of guy who, once he gets a good tune, isn’t going to be messing around with it a whole lot. So I probably would not have gotten one for the Camaro.

    I don’t know much about it, but I bet someone could figure out a way to use one device for multiple cars…I don’t really have the info to know for sure. But if that is possible, it could allow smaller shops to offer a dyno service that would have been too much to afford with traditional dynomometers.

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