Once again, our company pioneers in the field of tuning and brings to Greece the leading load dynamometer DR4-B2 of Dyno Revolt.

The DR4-B2 dynamometer is equipped with two electrodynamic brakes and has fully connected front and rear rollers, offering solutions even for our most demanding customers, as it fully simulates road conditions.

With 4000Nm of braking torque controlled by the innovative and ultra-fast interface, they guarantee the correct load of even the most powerful cars with appropriate measurements that provide accurate and repeatable results in every measurement.

Let's take the things from the beginning.

What is a load dynamometer?

At the moment the main types of dynamometers are two. Inertia dynamometers and load dynamometers.

An inertia dynamometer has a very heavy cylinder(s) and a speed measuring system. The car is measured at full throttle. The more power the car has the faster it can accelerate the heavy roller. Knowing the inertia of the cylinder and the acceleration, it is a simple mathematical calculation to determine the approximate engine power.

A cargo dynamometer has very light cylinders. It also has a speed measurement system. In addition, they have an electromagnetic retarder that applies a load to the rollers. This load is adjustable and can operate at constant speed as well as during acceleration. The dynamometer operator can vary the load from almost zero to very large. Knowing the inertia of the cylinders, the acceleration and the load applied by the retarder, it is a more complex calculation to get the power.

What are the main differences between inertia dynamometers and load dynamometers.

A) Steady State Tuning - Steady state tuning is the pinnacle of the load dynamometer. Because the load dynamometer has electromagnetic brakes to prevent the cylinders from accelerating, it can accurately vary how much load is placed on the car's engine. When the dyno is putting as much load on the engine as the engine is performing, the cylinders will stop accelerating and maintain a constant speed. That is, it can keep a car at 50% throttle and 2,500 rpm to investigate a failure that occurs under these conditions.

Because the motor is not accelerating, we call it steady state. During this time, the dynamometer measures the load between the brake and the car and outputs an active power figure. This is very useful for reprogramming because we can monitor the power gains or losses in real time to make many different measurements over a wide range of rpm and throttle opening. When the mapping is complete, the engine will have optimal ignition timing and fuel delivery throughout its operating range from idle to maximum power.
With an inertia dynamo there is no way to stop the cylinders from accelerating and therefore no way to maintain a steady state.

B) More accurate measurement - Because inertia dynamometers use a heavy mass to simulate the inertia of the car being tested, it is difficult to monitor small changes in power. The large mass of the cylinders results in very small changes in cylinder speed that the inertial dynamometer sensors have difficulty picking up. If the sensor and computer do not see the change in cylinder speed, the dyno graph will not show a drop in power. However, a load dynamometer uses cylinders with very little mass and measures power directly instead of calculating it. Rapid power drops will be picked up by the load sensor and displayed on the graph. This is very useful for finding problems and making sure your engine is working properly.

C) Load can be controlled - With inertia dynamometers the load applied to the engine as it accelerates is based on the inertia of the dynamometer cylinders. This inertia is set by the mass of the cylinders and cannot be changed. The inertia of the dynamometer cylinders directly determines how fast the car's engine will accelerate in each gear. Ideally, this inertia would be equal to the inertia of the car under test, but this is rarely the case. The idle will almost always be higher or lower than the car's idle and as a result the engine accelerates faster or slower than on the road. This can have an impact on how the engine is tuned and how accurate the dyno is in real world conditions. Because a load dynamometer

it is able to actively vary the load on the cylinders, it can change the acceleration rate as the operator wants. Realistic vehicle-specific loads can be used, or loads can be used that simulate hill driving.

D) Trouble Diagnosis - This feature goes back to the ability to control the load and set steady state. A load dynamometer is able to simulate road conditions in a safe environment while allowing the technician to monitor the car and its engine. A idle dynamometer is unable to accurately simulate all but a few road conditions, making it much more difficult to diagnose problems.

Does this mean that full throttle reprogramming is possible on an idle dyno, but a load dyno is required to reprogram the full range of an engine?

Wide open throttle mapping is possible on an idle dynamometer in a limited way. For example, let's consider measuring two cars with the same 150 HP engine. One car weighs 2,000 kg, the second weighs 3,000 kg. On the road the heavier car will accelerate much more slowly than the lighter car.
On an idle dynamometer both cars will accelerate at the same rate.
On a load dynamometer, the programmer can choose the rate (or let the software calculate the rate)
Acceleration rate affects not only the engine's fuel requirements etc, but combustion chamber temperatures vary significantly with acceleration and time under load. These variations require different matching values.

It's also worth mentioning that DynoRevolt's DR4-B2 dynamometer is fully synchronized. In other words, it has full synchronization on the front and rear rollers as standard. This means that the front and rear rollers rotate at exactly the same speed (hence the so-called "synchronization"). Such linked-axis functionality is usually offered as an option by other dyno manufacturers or not available at all.
The question is: is this timing important for today's cars?
The answer is simple - yes. There are many modern cars that, even when they have one driveshaft, monitor the second for speed – and measuring them on an out-of-sync dynamo shaft not only causes an ABS fault, but also a loss of power or strange traction control behavior. In many cars, even if you turn off traction control, it is not completely turned off – some functions remain, making a perfect power measurement impossible.
For 4x4 cars, the problem of measuring them without the front to rear axle connection comes from the active power management – many so-called 4wd cars are 2wd with the second axle occasionally connected to an electromagnetic clutch. Only timing belts make it possible to test such cars on a dyno (especially with a Haldex clutch or similar).

Not all dynamometers are created equal. In Greece, the dynamometers that exist are either outdated devices, or their users choose never to upgrade them. At Raceroms we could never choose such a device. Our customers are our driving force and we always want the best for them. For this reason alone we have chosen to buy only new and innovative devices, and we will always do the same.

Thank you,

Raceroms

The dyno is only available on our shop In Thessaloniki.

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