What can cause a high rpm
High RPMs in the cold is a result of combustion taking place in the engine. Your car is able to start because gasoline and air are coming together to form a spark. ... As soon as the vehicle turns on, the RPM goes back to normal, but that initial bump in RPM speed can take some drivers by surprise.Faulty Idle Air Control Valve (ICV): Some cars are equipped with an idle air control valve to maintain idle speed. ... Malfunctioning Throttle: A malfunctioning throttle system can cause both a high or low idle as well as an engine stall. A dirty air intake or cracked air intake tube is often the culprit.While extremely low rpm and high loads will damage your transmission right away, sustained high rpm may damage it over the long run. High rpm means more wear on the bearings and oil seals, and quicker transmission fluid breakdown.In case if it is a turbocharged, very high rpm would defiantly raise the inlet air temperature which might lead to early ignition inside the cylinders (if inter-coolers are not present) and might severely damage the engine. So considering all factors you can rev up to 75- 80% of your rev counter's maximum limit.Higher revolutions per minute equate to more fuel burnt in the same amount of time and more power produced. Because of this, most consider higher RPMs racing RPMs. Running at lower RPMs equates to higher torque and thus lower horsepower, while making higher RPM power outputs less torque and higher top horsepower.In general, the faster the RPM, the more power is generated, within a range of engine speeds. Some engines produce most of their torque at a very low RPM and then fall off as they get higher, such as diesel motors or large V8 engines in passenger cars.