Saltydawg
Well-known member
DiamondSCattleCo":vc97qst9 said:norriscathy":vc97qst9 said:Does this mean the diesel has more pulling power from a dead stop but with more horsepower the gas as the advantage at higher speeds?
Kinda, sorta, but not really HP is a function of torque. In effect its the amount of work you can theoretically do over time, as long as the load you are asking it to carry doesn't exceed the amount of torque available. So, your V10, with its higher HP should be able to accelerate faster, when its running at higher RPM, as long as there is enough available torque to allow acceleration. In other words, when loads are lighter, or the truck is empty.
Rod
Torque can be measured at the crankshaft of an engine. You can hook a scale to the output shaft of an engine and physically measure how hard its pulling...this is torque.
Horsepower is a computed number. It is a measure of the ammount of work done over a period of time...more hp = more work done.
Horsepower = torque * rpm/5252
From the formula you can see that the higher an engine rev's the more horsepower it will make...provided the torque numbers stay the same.
The biggest difference between diesel engines and gas engines is the compression ratios used in the motors.
Gas engines typically run a 8:1 - 10:1 compression ratio.
Diesels run 17:1 - 21:1.
Diesel engines "squish" the fuel mixture more so when it lights off you get a bigger bang. More power per pound of fuel being burnt...which is why diesels give better mpg when compared to similar powered gas motors.
The tradeoff is that in order to handle these higher compression ratios the deisel engine parts need to be physically more robust...they are heavier and bigger.
Because of this extra weight, throughout basically every engine component, the diesel cannot run at the high rpm's a gas motor can.
Gas motors can run at very high rpm's, and make gobs of horsepower, but this leads to poor fuel economy and lots of engine wear.
This is the biggest reason why Diesel engines last so much longer. The parts are built heavier from the start and they run at a much lower rpm.
Gas motors are perfectly capable of towing anything a diesel can given similar sized motors....its just the gas motor will get less fuel economy and wear out faster because it needs to run at a higher rpm level.
Occasional towing a gas motor is fine and it also allows you to accelerate a lot faster when you arent loaded. Nicer for daily driving IMO.
For heavy towing and just plain durability...you can't beat a well made diesel.