Torque and horsepower

[niky]

What if Car A have diesel engine and Car B have gasoline engine but both have same max Hp and max torque?

Obviously, they have different torque/hp curves to reflect their engine characteristics.

So assuming other things equal (losses, drag, weight, etc),

1. Who will reach 100kph first?
2. Who will reach 1km first?
3. Who will reach 10km first?
4. Who will reach 100km first?

My answer: Car A (diesel) on all counts because it would out-accelerate Car B during first few seconds and its initial lead distance would be maintained by the time they both reach their equal top speeds (remember, same max Hp, same losses, same drag, same weight, same etc).

Whaddya think?

edit: Let me just add equally skilled drivers, say Niky.

If they have identical HP and Torque, and identical gearing, Car B will win.

Why?

Because Car A makes torque and horsepower over a shorter range than Car B. Car A enters the next gear much earlier than Car B, who can delay the time-wasting shift much longer. Car A will have a longer reach through the gears, and will be able to reach 100 km/h at a much lower gear than Car B, and will be able to hit top speed in fewer gearshifts than B.

Of course, both cars are turbocharged. Because a naturally aspirated gasoline engine cannot have the same horsepower and torque as a turbocharged diesel engine.

A turbocharged diesel engine with more torque but the same horsepower as a gasoline engine also has similar problems. They're often as fast as gas engines with the same power (which is contentious, because turbocharged engines almost always make more power than the manufacturer claims), but if you wring out the gasoline engine, you can get better acceleration due to rpm limitations for the diesel. Basically, making between 200-250 hp is great, but if you only make it over 1000 rpm in a diesel, whereas with a gasoline engine, you can make it over a span of 2000-3000 rpms, you can only put that power down for a shorter amount of time in-gear.

But this all depends on gearing, the car, etcetera. There is no direct one-on-one comparison between gas and diesel. The only manufacturer I know that makes performance diesels and gas engines in the same mold, BMW, has a turbodiesel 3.0 that makes 286hp and 580 Nm of torque and a 3.0 gasoline turbo engine that makes 306hp and 400 Nm of torque.

The gasoline version, mind you, is mapped to make less power than it can, not for reasons of engine longevity, but in order not to be faster than the new M3.

Still, the gasoline car can hit 60 mph in 5.8 seconds, as opposed to the diesel's 6.1. (official figures). Torque is great off-the-line, but in racing, you're almost never below the powerband.