Limited revenues and Ministry of Transport.

[Anhartic]

I observed some time ago that my vehicle (OM642, 231 horsepower) does not exceed 3000 RPM in neutral. Initially suspecting a malfunction or limp mode despite the absence of an engine management light, I conducted research and discovered that this behavior is typical for my engine and is functioning as intended. It rebounds off the governor when engaged and in motion. This prompted me to contemplate the MOT, which I have scheduled for this Thursday. The diesel MOT includes revving the engine to the limits a maximum of 12 times for emissions and smoke testing. However, it is likely that my automobile is providing a distorted result owing to the restricted revolutions while stationary. Is this component part of the emissions manipulation program or only a mechanism to save the engine from over revving and potential damage? I was formerly a tester, and upon reviewing the current handbook, it is evident that it addresses a prevalent issue, stating that "if the engine revs are limited by design or software, it should be tested as presented." It seems rather deceptive, since it would undoubtedly emit more pollutants near the redline than at a modest 3000 rpm. Any observations?

[Strongspoi]

It is intentionally engineered to prevent revving over the specified engine speed in neutral to minimize the danger of damage. As a certified MOT tester, you are likely aware of instances when unrestricted diesel engines have failed catastrophically during the smoke test.

[Anhartic]

I have not had a testing license since the late 1990s, and that examination began in 1994. To my knowledge, there were no software limitations on derivatives at that time, just the governor. Several individuals involved in tuning, who had elevated governors, expressed dissatisfaction with the alterations at that time. I recall having a few snap belts. A warning was sent about the belt's impending replacement owing to mileage; yet, he persisted on testing it since he need the vehicle. "SNAP!" Vehicles with malfunctioning or removed limiters are often evident from the first rev, resulting in an immediate and significant failure. This is inequitable, since my automobile will not undergo a comprehensive assessment at its limit, perhaps emitting excessive smoke at 4000 RPM without detection at the testing facility.It does not, by the way!

[BuffUpdate]

I consistently do an Italian tune-up on our vehicles on route to the examination.

[Notef]

There was never a problem during the testing of my OM642, therefore I presume this has been considered?

There are few driving scenarios in which one would surpass 3000 rpm in a 3-liter V6 diesel engine. 🤔

[Lemmand]

I believe that diesel engines are subjected to various testing protocols nowadays.

[Anhartic]

I agree; it is beneficial for assisting me in passing the examination. However, it is rather deceptive to do the test at 3000 RPM whereas my ALFA was required to perform the same test at about 5000 RPM. This is only a topic for discussion.

[Cassole]

It is not really a cheat, since petrol engines consistently operate at greater revolutions than diesel engines. Examine the engine in the Honda 2000, which reached a maximum of 9000 rpm. 😱

[Anhartic]

However, they are not subjected to emissions testing at maximum revolutions, unlike diesel engines.

[Cassole]

Likely due to the differing production methods of the investigated combustion products?

The testing station will not be affected by the 3000 rpm restriction.