Engine Dynamometer Testing Well Worth the Investment

A visit to Boucher’s Automotive for a closer look into dyno testing.

Many racers and car enthusiasts love having a number associated with what their engine makes for horsepower. Running one’s engine on a dynamometer is beneficial in many more ways than just having a number to throw around while bench racing. Boucher’s Automotive Machine in Rowley, MA has a state of the art dynamometer facility in house so we headed over there in an effort to get a better understanding of the advantages of running an engine on the dyno before installing in it a car.

The dynamometer installed at Boucher’s is a “custom” Stuska Dynamometer capable of handling engines making up to 1500 horsepower. The term “custom” is thrown in the mix because Boucher’s builds horsepower in all shapes and forms including Big Block Chevies, Buicks, Straight Six’s, and Fuel Injected Hemis to name just a few. Therefore, the dyno needed the capabilities of running any of those combinations and many customized designs were implemented by owner Tom Boucher and his engineering consultant Vic Santos. Tom emphasized that he wanted lab conditions to make the dyno as repeatable as possible in an effort to find every bit of horsepower available for any given combination. Santos was able to design a system that does just that, as horsepower improvements as little as 1-2HP can be identified with every change.

Many people do not take advantage of the opportunity of running an engine on a dynamometer due to the financial investment. We asked Tom what some of the pros and cons were for a session of dyno testing. His first response, as expected, was that an individual gets to know how much horsepower an engine actually makes. For a racer, this is great because one will have an expectation for elapsed times and speeds before even going down the track. If the car seems to be off pace from the HP and Torque figures, then the driver knows its time to work on the chassis or other driveline components. After a dyno session, there is no second guessing the performance of the engine. This is just the beginning of the benefits. With the provided torque curves, a racer can have a converter built specifically to one’s engine combination, maximizing performance at the track. For the stick shift cars, gear ratios and can be pre-determined so the appropriate RPM band can be achieved. Preliminary tuning can be done on the dyno to get a carburetor or fuel map close and save some time at the track. Tom does note that tuning is only approximate as an actual run down the track can not be simulated so final “tweaking” will be needed once at the race track. Other adjustments such as ignition timing, cam timing, and valve lash can all be evaluated in a very controlled environment to see where maximum performance is reached. There is no second guessing track conditions, shift points, wind direction, or weather changes when trying to assess the performance of a change.

For any customer, breaking in a new engine is a huge advantage to do on a dyno over doing it in the car. Breaking in a cam is trivial as variables such as RPM, water temperature, and load can be readily controlled. With every engine monitored under severe scrutiny, if there is any type of problem, it can be diagnosed quickly and easily thus saving time and money. If an offseason change was made, it can be evaluated effectively before spending the time to put the engine in the car and waiting for appropriate weather to go racing. If the change is not for the better, the racer can make corrections and appropriate adjustments without losing any of the valuable racing season.

Tom also clarified that no two dynamometers are the same. Comparing horsepower from two different dynos can never be considered the only gauge of engine performance. Inlet conditions, dynamometer acceleration rates, weather conditions, and strain gauges are all analyzed slightly differently from facility to facility. The best recommendation Tom would give is to complete a dyno session at the end of the season before a rebuild. After improvements are made during the rebuild, placing the engine back on the same dynamometer will give an accurate evaluation in the improvement in power and what one can expect to see at the track. Every car fanatic should take full advantage of a dynamometer test session by contacting Boucher’s Automotive at 978-948-7343 to schedule an appointment.


Website By Mike Sawyer Motorsports