I hear everyone talking about AUC that it is the most important. My question is where on the rpm range is it most important? I know that you cant have your cake and eat it too, but wouldnt you want to give up some lowend for some topend to go faster? I have been doing a lot of reading about small duration cams with high lift that keep the lowend but pickup the highend, but at what point do you trade off lowend for topend. Obviouly, when your racing, your not within that 2000-5000 rpm range and the only time that matters is when your driving around. Wouldnt you want to go with a little more duration and lift if you will make more avg power in that 5000+ range?

Thanks
Jeremy

 

Area Under the Curve is important in the rev range you run the engine at WOT. If you launch at 5000, shift at 7000 and the revs never drop below 5000, build torque (and therefore hp) in that range. This won't make much of a daily driver, and it probably won't have a small duration cam. Part-throttle street driving will then become a challenge.

If it has to be multi-purpose, decide how bad its street manners can be, and design the engine accordingly. Yep, this will probably favor the high end. A multi-purpose car (strip and street) often doesn't do either thing well.

My $.02

 

Well said.

A "multi-purpose" car can do both. You need one thing or a combination if that's your bag... displacement, nitrous, force induction.
Lots of cubes can be docile on the street and still tear it up at the track. With nitrous, you can be as bad as you want to be. Same with forced induction, although it's a bit more of a chore getting those cars to turn the times at the track. Pick your poison but for me, cubes are the way to go.

Mike