Chassis Dynamometer Service

The ability to increase the power output of the engine of the vehicle is only valid if said increase can be utilized in a safe and reliable manner on the street or on the track.  First and foremost, the engine must be managed through modifications of the factory ECU or installation of an aftermarket ECU.  Secondarily, even the best ECU can grenade an engine with the wrong settings on the fuel and ignition.  It is therefore imperative that the engine be loaded in a manner which allows ample time at given load-RPM points in the fuel and ignition mapping to allow the tuner to optimize these settings.  Oprimize does not just mean from a power production standpoint, but also from a safety and transient response standpoint.  The only viable way to properly tune the engine in is with the use of a chassis dynamometer and also some touch-up work on the street (usually the driveability only).

We have an in-house loading dynamometer which allows for the engine and driveline of the vehicle to be loaded in a safe and effective manner.  Our Land and Sea pod chassis dyno setup allows the user to remove the wheel and the tire from the equation.  Once mounted to the chassis dyno, the engine can be loaded.  Loaded means point holding at any given RPM and/or sweep testing at a predetermined rate of sweep.  In addidition to this, various driving simulatiuons can also be run during testing.  This machine is setup for serious tuning and research and development, not for doing sweep tests to acheive a dyno sheet for bragging rights.  The multi-channel data acquisition system allows full data logging of inputs.  These can range from single cylinder EGTs to manifold pressure and the like.

The machine works by using a large Eddy Current Absorber which is modulated through PWM methods to acheive the desired load curve.  There is no water cooling required and except for extremely high HP cars, the dyno can generally lock and hold more that your engine can make for any duration of time without overheating.  Force is measured by way of a calibrated S-beam load cell which is a fixed distance from the center of rotation.  Speed of the hub is measured and compared to the engine's speed and a resultant HP number is calculated.  Tire pressure doesn't mean anything in this equation.

Consider the benefits of this type of tuning aid as compared to a rolling-road dynamometer:

  • Orders of magnitude safer, as the vehicle cannot go anywhere even in the nearly impossible scenario that it falls off the machine.  There are no straps to break or other safety concerns
  • Ability to load and hold a given RPM point, regardless of load input value (assuming within limits of machine)
  • Tire damage is not possible and there is no risk of buring up a tire on the machine due to over strapping or excessive loading of the tire under extreme power levels
  • Sweep testing with variable sweep rate.  Unlike an inertia only dyno where the rate of sweep is determined by the power of the vehicle, this machine can set the sweep rate, regardless of the power of the vehicle (again within the limits of the machine).  Want to run from 2,000-8000 RPM in 30 seconds?  No problem.  Want to blast from 6,000-8,000 RPM in 5 seconds?  No problem.  
  • Ability to fully load your turbo car and data-log temperatures, pressures, etc.

Once you have had the luxury of hooking up and tuning on this type of machine you will not want to convert back to a standard inertia style machine.  We had a user come to us to do a couple of hits on this machine, swearing his fuel maps were "perfect".  After pulling the car on about a 15 second sweep pull with him applying the load, the car was emitting a lot of black smoke and barely able to pull through.  He swore his fuel maps were perfect and that the machine was overloading the car.  The fact of the matter is the car had been tuned on the street and the maps were off...way off.  Understand that the dyno only holds the RPM set point it is told to load.  The load is applied by the engine...and if the mapping is off it will be very apparent on this type of machine.  The same issue was never found on the street or an inertia pull because the duration under the same load was minimal.  Inertia machines are great for strapping down and getting a quick power number but make no mistake they are a poor (at best) tuning dyno.  People often look at this machine and discount it by stating there is no way it can possibly perform like a roller inertia machine.  The problem isn't the machine, but rather a lack of understanding as to how each machine works.  In short they're right...it doesn't perform like an inertia machine, but rather performs better and more safely.

The chassis dyno is capabable of holding roughly 750 ft-lbs continuous (lock and hold) for up to around 30 seconds.  Lower torque levels can be held much longer.  Time your next inertia sweep and see how long it takes.  For most moderate RPM engines, this translates to close to 1000 RWHP.  We are currently setup for RWD and FWD vehicles with the following hub patterns:

  • 4X100mm (VW)
  • 4X108mm (Ford, Porsche)
  • 4X114.3mm (Ford)
  • 5X100mm
  • 5X114.3mm (Ford)
  • 5X110mm (BMW)
  • 5X112mm (Audi, VW)
  • 5X120mm (Mercedes Benz)
  • 5X130mm (Porsche :)

Our machine is available to rent on an hourly, daily or weekly rate by appointment only.  Rates are listed below:

  1. Initial Hookup and 1 Hour of Pulls: $150.00 (as many pulls as you want to make!)
  2. Hourly Rate up to 3 Hours: $100.00 per hour
  3. Hourly Rate from 4-8 Hours: $75.00 per hour
  4. Full day rate (assumes more than 1 full day): $500.00 per day

Stop tuning on machines that cost you an arm and a leg and don't properly load the engine.  If you're still tuning on the street consider you can get a more effective tune by renting our machine without risking losing your driver's license or jail time to get those last few high load-RPM cells in your fuel maps. 

© 2011 Kuhn Performance Technologies.