What is horsepower and torque and how do they relate to a car being fast or a truck having a towing capacity?
In: Engineering
The HP and torque numbers don’t matter for speed and towing as much as vehicle weight, transmission & final gearing, brakes, and, suspension set up. My V-8 car, my 4 cylinder car, and a big rig truck all have about 200hp.
My V-8 is rated to tow up to 5,000 pounds, the 4 cylinder isn’t rated for towing and it isn’t recommended, and the big rig can tow 45,000 pounds. This requires torque. The V-8 pumps out close to 200 ft pounds of torque, the 4 cyl pumps out 140, and the big rig pumps out closer to 1,200.
The 4 cyl is the fastest out the group, followed by the V-8, then, very far behind is the big rig.
Now for the transmissions. The V-8 has a simple 4 speed automatic, with one gear for overdrive. The 4 cyl has a six speed manual with 2 gears for overdrive. The big rig can have up to 21 or more forward gears, 2 or more reverse gears, and overdrive is based on build specs & final use, plus customer input.
The 4 cyl has a red line that lets it spin up to 8,000 RPM. It has lower final drive ratios than the standard model, and spools up quickly to those speeds. The V-8 has a red line of about 5,000 RPM and is geared for top speed and acceleration. It winds up a bit slower, but it’s no slouch. The big rig is tached out at 3,000 RPM, and accelerates so slow, you can time your shift without using the clutch between shifts.
Engine sizes: The 4 cyl is a whopping 2 liters, the V-8 is 4.6, and the 4 cylinder big rig starts off around 12 liters.
Edit: Hit send too soon.
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