More on higher HP vs. higher torque.

[glhs875]

I had my interest sparked from another thread. So I have done alot of math between 2 different power curves, but also similar when seen on a graph other than rpm's, and using in theory by keeping the same car (weight), trans., & tire diameter identical. Traction is no issue, this is in theory.

Engine #1 specs- 400tq @ 3500rpm/ 200HP @ 5250rpm

Engine #2 has rpm's doubled for torque and HP over engine #1 with the torque and HP reversed. 200tq.@ 7000rpm/ 400HP@ 10,500rpm.

From a 1/4 mile calculator a 400HP engine in a 2500lb car could run 10.75 @ 127mph in the 1/4. And the 10,500rpm engine would need a 6.32 final drive with high gear being a 1 to1 ratio on 26" tall tires to cross the line @ 10,500rpm.

Now, with any engine, maximum acceleration occurs at peak torque no matter what the HP is, and also rpm level, with it diminishing at a certain rate if the torque is dropping below peak even if HP is still rising.

From the math I have done, both engines in the same car can have virtually identical aceleration, but the low torque/lower Hp & rpm engine can use a 3.16 final drive vs. the low torque/higher HP & rpm engine needing a 6.32 final drive to arrive at peak power at the finish line. And if both were shifted at peak power into the next gear both would have identical torque available at that point and still with them having different final drive ratios but with the same tran. ratios for each gear. And a difference in acceleration between the 2 could be very easily made if the power curve is altered in anyway and could give either engine an advantage. It is very complicated!!!

In my opinion, I would lean towards the engine that had the most average torque available for each gear being the winner. But I could be wrong.

[GLHSKEN]

Torque wins races on the 1/4 mile.... HP is nice, torque (I'll say USABLE torque) is better. Shifting the torque peak 4-500 rpm on these cars is where it is at..

[turboshadow]

*Quality* power is better than lots of power....

[Greedy]

I have always been a big fan of Torque for the street.
I remember beating up a Civic Si (1.6 DOHC) in my 2.5 TI Spirit the guy was incredibly suprised to say the least.
He was talking to me about his car and told me how much power he had(I can't remember how much)I told him mine probably didn't have that much and He said how did you beat me?Your car is heavier?I told him first of all you have two passenger so my car is not that much heavier if at all, plus you might have 10 hp on me but I have easily 75ftlbs of torque on you at every rpm and my power peak is lower than yours!
He didn't understand,I said in a quartermile how much time do you spend at your power peak (whatever rpm that was)??? He didn't know I said probably less than 3 seconds,so I oversimplified it for him... for 3 seconds you have 10(hp) more power than me for 12 or 13 seconds I have 75(ftlbs) more power than you.
I am not sure if he understood me or not but at least he was cool about it.