I don't mean to come across like an idiot, but can someone please explain what *torque* is? I have a general idea, but I am not a mechanic and it seems every truck commercial on TV, and programs dedicated to trucks there is a lot of emphasis put on torque. If someone can explain it in layman's terms I sure would appreciate it.

Thanks,

Rich

 

http://vettenet.org/torquehp.html

It's a good primer.

 

OK, so what's the advantage of low end torque? I notice that Chevy says "more horsepower than Ford" with no mention of torque so there must be trade offs. My guess is that off the line torque wins but over distance horsepower wins. Would be nice to know all the trade offs, milage, red line, compression ratio, reliability. Any gear heads out there with more info?

 

In laymans terms torque can be defined as when a man wakes up in the morning trying to use the restroom and hit the toilet he has to bend over to hit the water

 

Torque basically indicates how fast you can accelerate, while horsepower indicates how fast you can go. "Low-end torque" means a significant amount of the torque is available at lower rpms. This is good for pulling a trailer, for leaving a stoplight, ripping out stumps, etc. If the torque peak is up higher then accelerating from 50 - 70 mph would be better. Changing the way the engine breathes, through valve timing and intake and exhaust design, computer programming, etc, can change the torque vs rpm curve. Horsepower is fun to advertise, but it really doesn't come into play until the horsepower required to push the vehicle through the air is higher than the available horsepower of the engine at that rpm - once you hit that point, that's your top speed. Interestingly, a lot of vehicles with overhead cam engines are often set up for higher horsepower, which means their torque peak is at higher rpms - just what you don't usually want with a truck. Hope that helps!

 

Low end torque (i.e. more power at lower rpm) means efficient, useable power. The 2004 5.4L F150 hits peak torque at between 1,900 and 2,000 rpm. The F150 in overdrive at highway speed is cruising very close to this rpm. Therefore, at highway speed, in overdrive you basically have the full torque of the engine available to move large loads down the road.

I tow around 8,400 lbs regularly with mine, frequently in overdrive.

If the torque peaked at say 3,500-5,500 rpm like some engines, then you would have only a percentage of your engines power available at cruising speed. Therefore, you may have to tow at a higher rpm in a lower gear to take advantage of more of your engines power. It's likely that this would result in poorer fuel economy and more engine wear.

If your looking for a truck to tow large loads with, look for one with lots of torque that peaks low or better yet at the rpm you will normally drive at.

If you want to drag race, look for a truck with pleanty of horsepower and a torque curve that peaks at about the same rpm as the horsepower does.

 

Torque is a measure of the twisting motion of a shaft. You are applying torque when you tighten a lug nut with a wrench. The English unit of measure of torque is pound-feet. If you move your hand out on the wrench handle one foot from the center of the lug nut and you apply one pound of force on the handle, you are applying one pound-foot of torque on the lug nut. Power is defined as work per unit time or in this case, the amount of torque applied in a specific amount of time. The formula for horsepower is; HP=torque X RPM/5252. For example, if an engine is putting out 300 lb-ft at 2000 RPM, it is generating about 114 HP. To put it simply, high torque is good for pulling and high HP is good for acceleration.