What rpm is it idling at? 25% Load at idle in park is about 10% higher than it should be, which would point to an issue with the MAF/tune.
Torque, simply, is the ability of a vehicle to perform work — specifically, the twisting force applied by the crankshaft. Horsepower is how rapidly the vehicle can perform that work. Because there is generally a limit on how fast you can spin an engine, having higher torque allows for greater horsepower at lower rpms.
Consider a car engine running at constant speed. That is, the crankshaft of the engine rotates at constant angular velocity while each piston moves back-and-forth in its cylinder according to the rules of simple harmonic motion.
Maintaining higher RPM not only increases the temperature of the engine but also degrades the quality of the engine oil and which results in frequent oil changes. Also, the life of the engine deteriorates when it is continuously abused by the driver by red lining it in the shorter gears.
All Answers (7) usually, they have an optimum point in the middle. after that point, in a constant load which means that fuel quantity and air remain constant, an increase in speed of piston doesn't let fuel burn completely (decrease of time). so it causes a decrease in torque.
More pedal sends more fuel in engine. When more fuel burns, more gases are produced. More gases push the piston harder, making the RPM go higher.
If you increase the torque you increase the speed UNLESS you increase the load. The important thing to remember is that with electric motors there is a back-EMF (a motor is a generator too) which increases with speed and that limits the effective voltage and thereby the current and thereby the torque.
The medium speed four-stroke engine (250 – 1200 rev/min) is used for the auxiliaries such as alternators and also for main propulsion with a gearbox. A four-stroke diesel engine resembles a gasoline engine as it works on the four-stroke cycle, that is: admission, compression, power and exhaust.
For example, a piston in an automobile engine which has a stroke of 90 mm will have a mean speed at 3000 rpm of 2 * (90 / 1000) * 3000 / 60 = 9 m/s.
Car engine rpm increases as you press the accelerator, as does power — at least to a point. An engine doesn't necessarily produce its maximum power at its highest rpm. Engine specifications typically present the peak horsepower figure followed by the rpm at which it occurs, such as 252 hp at 5,600 rpm.
You can simplify the formula with a little math trick. Divide the numerator and denominator in this equation by 2, and you'll get the same answer. In other words, multiply the stroke by the RPM, then divide by 6. With this simpler formula, we'll calculate the mean piston speed with the stroke increased to 4.500 inch.
Diesel engines works with 14 to 24 compression ratio while gasoline engines at 7 to 9.5 CR. This difference appears in the high pressure rates of combustion inside the combustion chamber.
That's 3,480 fpm so the commonly accepted limit of 3,500 fpm is pretty safe. Start revving those cast pistons to 7,000 rpm and you'll be knocking the skirts off of them in short order. Forged pistons can take the abuse so you're good up to about 5,500 fpm and more, especially in short bursts such as drag racing.
Low speed diesel engines like the MAN S80ME-C7 have achieved an overall energy conversion efficiency of 54.4%, which is the highest conversion of fuel into power by any single-cycle internal or external combustion engine.
That means in a four stroke engine the shaft rotates twice (two revolutions) for every four stroke cycle, which means one power stoke for every two revolutions of the crank. So, if the crank is turning 1000 times per minute, that would be 500 power strokes (firing of the spark plug) on each cylinder in that one minute.
Max RPM is the limit that the engine can take before severe damage. Running at or near max RPM for extended periods will drastically reduce engine life. Engines are usually more efficient at lower RPM as well. So early shifting etc will increase your gas milage.
"it does between 2,000 and 2,100 rpm at 60 mph. Then at 70 mph, it's doing close to 2,500 prm.
The idle speed should feel consistent without skipping or slipping. In most of today's cars, an idle speed of 600 to 1000 RPMs is average. If your car is idling rough, though, it won't feel smooth. The RPMs will jump up and down, for example, or they'll fall below 600 RPM (or whatever is typical for your vehicle).
The engine will operate at idle and the rpm will indicate between 800 and 1000 rpm. RPMs are the revolutions per minuite that your engine turns. For a zero reading your engine must not be running. Most engines idle at between 600 to 900 RPM.
The most likely cause is that your clutch is slipping. Either because the mechanism isn't working properly (rare but possible) or the clutch is worn (very likely). Have you checked your transmission oil level? Low oil level could cause your symptoms.
I would say anything up to 9000 rpm should be fine. That's why they call it redline. If 7750 was its safe limit then that would be the redline. Now 10000rpm might be considered as unsafe.
Get bigger tires. Get a differential gear set with a lower ratio, and/or get a overdrive transmission or bolt on system. These are a the options to lower your revs at top speed, but know this. If you don't know what you are doing, it can get expensive fast, and you might move your rpms out of your optimal powerband.
