High idle speeds waste fuel, cause extra wear and tear on your engine, and can be unsafe as well. If your foot should slip off the brake as the engine revs, it could cause your vehicle to lurch forward, putting other drivers and even pedestrians at risk.
Running an engine at idle causes twice the wear on internal parts com- pared to driving at highway speeds. Idling will increase maintenance cost and shorten the life of the engine. Myth: Diesel engine idling does not waste much fuel. Fact: Fuel is one of the largest operating expenses in our industry.
Idle the engine at 900 RPM to 1200 RPM.
This ensures the oil has sufficient pressure to reach the top of the heads in the engine.
Diesels cannot run at high RPMs due to low fuel burn rate, whereas gasoline engines can. Because the redline of diesel engines is lower, the parameters of the engine are typically optimized for running at these lower RPMs.
Over the course of a year, a long-haul truck could idle for about 1,800 hours, using nearly 1,500 gallons of diesel, which is $5.82 per gallon in the US as of June 2022. For one heavy truck, the cost of idle fuel waste averages about $8,730. Idling a heavy-duty truck consumes about 0.8 gallon of fuel per hour.
In order to start a diesel engine and keep it running in cold weather, you must make sure you allow plenty of time for your engine to warm up. If you do not let your engine warm up before driving, you will make it work harder than necessary, which will lead to problems later on.
It turns out diesel motors are very hard to start in cold weather, so to avoid the down time and cost waiting for a mechanic to come out to start your rig, the drivers would not shut down the engine.
After all, when redlined, an engine can sound like it's about to blow. However, there's no need to worry. Redlining will not damage an engine or cause it to explode, no matter how cruelly you treat it. Therefore, revving the engine to its maximum speed several times a week is not a problem.
Over-revving can cause damage to your valve train by causing a valve to stay open for too long – this leads to valve float. Valve float occurs when a valve is stuck in between open and closed. This will cause an immediate loss of power.
High RPM – Idle speed is measured in revolutions per minute (RPM). For most 2 liter and below sized engines the vehicles, the standard idle speed should be around 750 RPM (when the engine is warm). If your car's RPM is above 900 with a warm engine while idling, it is likely using too much fuel.
Idling a heavy-duty truck consumes about 0.8 gallon of fuel per hour. Even when diesel costs as little as $2.50 a gallon, fuel for one 10-hour rest period will cost $20. Typically, a long-haul truck idles about 1,800 hours per year, using about 1,500 gallons of diesel.
One of the most common diesel truck problems is letting dust, dirt, and grime build-up on your engine. This will make it easy for contaminants to get into your system and cause damage. As mentioned above, make sure the three main systems, oil, air, and fuel, are kept clean and inspected.
Diesels have better idling characteristics than gasoline engines and can idle four times as long on the same amount of fuel. Cold weather starts for diesel engines require fuel additive assistance or block heaters, either of which could damage the engine.
Idling wastes fuel – and money. Vehicles get ZERO miles-per-gallon while idling. Larger vehicles tend to waste more fuel than smaller ones. Idling can also cause greater engine wear-and-tear over time, resulting in higher maintenance costs.
Diesel engines never rev as high as petrol engines due to the fact that the piston has to travel further for its full rotation, while a petrol engine uses its shorter stroke to move the piston in quicker bursts, meaning the engine speed can be faster.
As a consequence of a higher compression ratio (longer stroke and turbocharger), diesel engines produce more torque which means you get more acceleration off the line.
It depends on what is meant by “high” rpm. There is a red line on the tachometer. Using this range of engine speed is wearing on the engine and may break something if used habitually and especially if the rpm is held there. Highway driving in the proper gear is actually good for the engine in terms of “cleaning” it.
It is simply much more expensive to make high reving Turbo petrols. Need much better balanced rotating components, lighter & stronger internals. NA engines may rev to much higher rpms but they aren't making much torque at those RPMs, high horsepower is simply coming from more revs( hence more bangs per minute).
When not in motion, the vehicle should ideally stay between 600-1000 RPM. However, if you're idling in cold weather conditions, the RPM may jump higher in order to keep the engine running. If you notice that the car is idling at higher RPMs, it could be because of reasons like: Fuse in the Idle Air Control (IAC) motor.
It's also just as important to let your diesel cool off before you shut it down. A turbo timer will do this automatically for you, because if it gets shut off too soon, oil will overheat, break down, and destroy turbo bearings.
And finally, don't shut down your engine without letting it idle for 5 to 10 minutes to cool down. Diesel Exhaust Fluid injectors need to be cooled down to extend their life. As well, turbocharger bearings depend on engine lubricant for cooling and that flow stops when the engine is shut off.
To summarize, all engines with a cooling system need a cool down after long sustained full load. This means everyone towing or running fully loaded. Once you shut the engine off, the engine cooling system will continue to get hotter before it cools down.