Car Question: Relationship Between Engine Size and Horsepower

[duke]

Pacfanweb,

"Disagree. There is NOT always plenty of torque. Having small displacement DOES mean you'll not have as much torque as a larger engine.

The ONLY way to have more torque, is to have more horsepower. They are directly connected. "

True statement only when comparing two engines with all else being equal. But what I was trying to say is even if you have a small BUT high reving engine you can always obtain more torque through gearing (mechanical advantage). Like I said, there is more than one way to get torque for your particular application. Correct me if I am wrong.

 

[notfred]

I didnt read the whole thread, but I'm wondering where you got the idea of a 190hp 4 liter mustang?

Did you mean a 265hp 4.6 liter mustang?

 

[Pacfanweb]

<<True statement only when comparing two engines with all else being equal. But what I was trying to say is even if you have a small BUT high reving engine you can always obtain more torque through gearing (mechanical advantage). Like I said, there is more than one way to get torque for your particular application. Correct me if I am wrong. >>

Duke: Yes, you can multiply the torque by transmission and axle gearing, but this is done on all cars, so it really doesn't help if you have two identical cars with, say the engines I mentioned previously.....the bigger engine will always win, regardless of gearing.
Lower gears (higher numerically) would be much more help to the smaller engine, since its power peak is higher.
Basically, the argument for the larger engine with more torque would be that it doesn't have to work as hard to get the same power, therefore it needs less gear, so it saves wear and tear on internals. The flip side would be that it doesn't bother the smaller engine to rev more since there is less mass churning around in there.

I understand what you're saying, though, and you are correct. You can get more torque multiplication by lower gearing. It can't really make up for cubic inches, but it can make a difference vs. another car with a similar power curve.