The Packard Proving Grounds is in possession of a unique artifact of Detroit history, one that was a common sight at the Proving Grounds. This artifact – which is called the Packard Towing Dynamometer – was based on a production 1928 Packard 526 Sedan that was subsequently modified by engineers at the Proving Grounds. The Towing Dynamometer served as a rolling automotive test bed and was used extensively on the high-speed test track from the late 1920s through the decade of the 1930s. We are fortunate that it has survived and pleased to be its caretaker.

At the Proving Grounds the engineers at Packard set out to test the durability of Packard automobiles. One way to accomplish this goal was to drive a Packard on the test track for days on end – 10,000 miles in10 days – and then bring the car into the garage and tear it down completely. By measuring the size and tolerances of moving parts and by looking for indications of wear, they could see how the components stood up to the endurance test. Given Packard’s devotion to engineering excellence and durability, any part that showed excessive wear would need to be redesigned or made of a new material.

An endurance run on a high-speed track tells one story. But what about increasing the load on the car under test? Could increasing the drag on the car also increase the likelihood for wear? Well, that was the purpose of the Packard Towing Dynamometer.

The Towing Dynamometer was designed to apply any type of drag load to the car being tested. The load could be increased or decreased by the engineer sitting in the dynamometer car being tested. Most likely the car included tools and meters to measure the load generated. Perhaps the engineer would write notes about the load and the duration into a notebook. Perhaps data was automatically captured on a roll of paper in an instrument built for that purpose.

In the period film titled “How Packard Proved a Packard, Part I and Part II,” Packard demonstrates how the 7th series cars were being tested at the Proving Grounds. Near the end of Part I, we are treated to the sight of the Packard Towing Dynamometer hard at work on the test track. Not only do we get to see the exterior of the car but the film shows a portion of the dashboard and gauges. In the film we can see two gauges clearly and part of a third gauge. The gauges are marked like speedometers from 0 to 100, and there is a small switch and a dashboard lamp. Fortunately the Towing Dynamometer still has this dashboard complete with a set of gauges.

Given its historical importance, the Proving Grounds has decided to restore the Packard Towing Dynamometer and we need your help. We are looking for additional photographs of the car from the 1920s and 1930s – especially photographs of the engine. Any stories about the car and how it was used at the Proving Grounds would be valuable. Information on instruments or meters that might have been used at the Proving Grounds and with the Towing Dynamometer are important to us. It is our aim to restore this piece of Detroit automotive history as accurately as possible and we need this information to guide our restoration.

Funds for this project are being provided by people who donate to the Packard Motor Car Foundation. The PMCF is the foundation that oversees and restores the Packard Proving Grounds. We welcome your generous donations to help us complete this important project – a piece of Proving Grounds history that holds a place of distinction in Detroit automotive history. When you send your donation to the PMCF, please write “Dynamo” in the subject line so we can acknowledge your donation.

The Packard Motor Car Foundation, 49965 Van Dyke Ave., Shelby Township, MI 48317. You can also go to our website at or call (586) 739-4800.