</font><font color="blue" class="small">( This is why NASCAR engines turn such incredible RPMs. The faster the engine turns, the more power it can make.
One thing to always remember is that it is torque that breaks parts, not RPM.
Another thing to remember is that most horsepower claims are marketing untruths.)</font>
I agree and disagree both. I agree that engine speed will make more power assuming the valve timing is specific to the range of speeds you want to make that power in. I assume you meant that though.
What I disagree with, is that torque breaks parts. I've seen the opposite, in that engine speed puts more wear on parts. Granted. for the typical diesel engine, which never sees engine speeds anywhere near what a gas engine ungergoes, your statement is correct. For a gas engine though, increasing engine speed increases side loading (due to radial forces at the rod journals) of the rotating assembly by the square of the crankshaft speed. Torque puts more torsional loading on the crank, rather than radial loading, which is designed to take that torsional stress. The higher engine speed requires more oil pressure to keep rod and main bearings alive, and the additional shaft speed causes valvatrain deficiencies to become more noticable. Based on my own experience, a 600 hp / 460 ft-lb, naturally aspirated, 333 CID Ford engine had much more wear than a 940 hp / 950 ft-lb turbocharged 306 CID Ford engine, upon inspection after dissassembly. The NA engine made power from 4500 RPM through 7500 RPM, while the turbocharged engine made power from 3000 RPM through 6000 RPM. The NA engine had alot more wear on the rod journal bearings and the main bearings than the turbocharged engine. It also had alot more wear on the thrust bearing, but that may be more clutch related than speed related. The rotating assemblies were both high quality, but the NA engine had all lightweight billet components, while the turbo engine just had run of the mill heavy duty forged parts. I guess I'm getting off subject here, but I am of the opinion that higher speeds kill engines faster than just alot of torque. Granted, for a diesel running less than 3000 RPM, it's pretty moot point, engine speeds that low won't hurt enything.
One thing to always remember is that it is torque that breaks parts, not RPM.
Another thing to remember is that most horsepower claims are marketing untruths.)</font>
I agree and disagree both. I agree that engine speed will make more power assuming the valve timing is specific to the range of speeds you want to make that power in. I assume you meant that though.
What I disagree with, is that torque breaks parts. I've seen the opposite, in that engine speed puts more wear on parts. Granted. for the typical diesel engine, which never sees engine speeds anywhere near what a gas engine ungergoes, your statement is correct. For a gas engine though, increasing engine speed increases side loading (due to radial forces at the rod journals) of the rotating assembly by the square of the crankshaft speed. Torque puts more torsional loading on the crank, rather than radial loading, which is designed to take that torsional stress. The higher engine speed requires more oil pressure to keep rod and main bearings alive, and the additional shaft speed causes valvatrain deficiencies to become more noticable. Based on my own experience, a 600 hp / 460 ft-lb, naturally aspirated, 333 CID Ford engine had much more wear than a 940 hp / 950 ft-lb turbocharged 306 CID Ford engine, upon inspection after dissassembly. The NA engine made power from 4500 RPM through 7500 RPM, while the turbocharged engine made power from 3000 RPM through 6000 RPM. The NA engine had alot more wear on the rod journal bearings and the main bearings than the turbocharged engine. It also had alot more wear on the thrust bearing, but that may be more clutch related than speed related. The rotating assemblies were both high quality, but the NA engine had all lightweight billet components, while the turbo engine just had run of the mill heavy duty forged parts. I guess I'm getting off subject here, but I am of the opinion that higher speeds kill engines faster than just alot of torque. Granted, for a diesel running less than 3000 RPM, it's pretty moot point, engine speeds that low won't hurt enything.
