mkirsch wrote:
The problem with looking purely at MPG is that you totally ignore the extra up-front cost of a diesel, which, despite what many claim, you will *NOT* get back when you go to sell/trade the truck. You will get a *FRACTION* of that amount back. Plus diesel is generally more expensive than premium gasoline.
That up-front money can go in the bank and buy a lot of gasoline over the life of the truck.
It will take a LOT of miles to just break even on gas vs. diesel based on MPG alone.
Actually that discussion was just had in another thread. Given the 50% difference in fuel economy, even if a diesel engine's only advantage was MPG, the $8,000 option would pay for itself in something like 50,000 miles. Of course the diesel also has much more power than a gasoline engine and the engine will last much longer, so mpg is not the only advantage.
I have seen that the debates between gas and diesel here get ugly so I don't want to get too deep into it, but I do want to make one point. For vehicles subject to heavy use, the market has pretty much spoken. Commercial vehicles that are as heavy as our trucks are with campers attached are almost universally diesel. I have seen UPS and FedEx employ some gas trucks recently, but those are the exception rather than the rule. If there was any superiority--in maintenance cost, fuel cost, purchase cost, etc., I would think that commercial vehicles would use gasoline. But they don't. This is true even for vehicles used only for local delivery or use (think tow trucks or couriers) or long haul. All use diesel.
Gas engines are simpler, light weight, and certainly capable of doing the job, but diesels are more durable, efficient, and powerful. That's why they are the near-universal choice in this weight range, and if anything, that's more true today than it has ever been, despite the insane changes to emissions in 2007.
restlessways wrote:
This is not exactly true. "Power" is the rate at which work is performed. "Torque" is the measurement of turning force. Power is a product of the torque that the motor generates. It is path dependent. Without torque, you have no power.
Torque is still not a measurement of power, and torque is still useless without applying a rate to it. Generating force isn't the same as performing work.
If you read carefully, I don't disagree with anything you've said except that it is absolutely true that torque is not a measurement of power. It's no different than saying that volts are not a measurement of electrical power. Torque is related to power, as is voltage is to electrical power. But torque is not a measurement of power.
