[Z06] under the curve
Thread Starter
Safety Car
Joined: Dec 2006
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From: NC
2025 Corvette of the Year Finalist - Unmodified
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under the curve
I have heard the term under the curve in reference to dyno numbers and really do not understand . Can anyone explain to me what exactly this means? I need knowledge! 
Thanks
Thanks
Race Director
Joined: Jul 2007
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From: Texas Hill Country
many people (most) and magazines and manufacturers typically (or traditionally) focus on peak power numbers (whatever the highest point of the curve is - ie, 350 HP @6500 RPM).
when people say that looking at what is under the curve is more important they are referring to the fact that it is more important to have good power through the whole RPM range rather than just a good peak number. it makes you faster.
an extreme example would be comparing a little 1.5 liter 4 banger with a HUGE turbo that makes 100 HP until it gets to 10000 RPM when it finally has enough exhaust flow to spool the big turbo and suddenly it makes 650 HP at 10000 RPM. compare that with a built LSX that makes 400 HP at 3500 RPM and 600 at 6500 RPM. which would be faster? which would be better to drive?
If you graph my numerical examples, you will see that the LSX is a bigger overall "mountain" than the turbo 4 which straight lines until it goes straight up.
If you compared the two by peak numbers, you might get the impression that the 4 banger is "faster." however, it will not be.
the idea is that the earlier in the RPM range you can get a bigger number, and the longer through the RPM range you can sustain it, the better.
when people say that looking at what is under the curve is more important they are referring to the fact that it is more important to have good power through the whole RPM range rather than just a good peak number. it makes you faster.
an extreme example would be comparing a little 1.5 liter 4 banger with a HUGE turbo that makes 100 HP until it gets to 10000 RPM when it finally has enough exhaust flow to spool the big turbo and suddenly it makes 650 HP at 10000 RPM. compare that with a built LSX that makes 400 HP at 3500 RPM and 600 at 6500 RPM. which would be faster? which would be better to drive?
If you graph my numerical examples, you will see that the LSX is a bigger overall "mountain" than the turbo 4 which straight lines until it goes straight up.
If you compared the two by peak numbers, you might get the impression that the 4 banger is "faster." however, it will not be.
the idea is that the earlier in the RPM range you can get a bigger number, and the longer through the RPM range you can sustain it, the better.
Racer
Joined: Nov 2002
Posts: 397
Likes: 0
From: Auburn AL
Area under the curve refers to the amount of white space on the paper under the power curve. If you were to calculate the area of the above mentioned LSX and "4 Banger" cars and compare the two you would notice that the "area under the curve" of the LSX is much larger than the one for the "4 Banger"
Hope that helps
Greg
Hope that helps
Greg
Thread Starter
Safety Car
Joined: Dec 2006
Posts: 3,937
Likes: 1,925
From: NC
2025 Corvette of the Year Finalist - Unmodified
2024 C7 of the Year Winner - Unmodified
2023 C7 of the Year Finalist - Unmodified
2019 C6 of Year Finalist (performance mods)
many people (most) and magazines and manufacturers typically (or traditionally) focus on peak power numbers (whatever the highest point of the curve is - ie, 350 HP @6500 RPM).
when people say that looking at what is under the curve is more important they are referring to the fact that it is more important to have good power through the whole RPM range rather than just a good peak number. it makes you faster.
an extreme example would be comparing a little 1.5 liter 4 banger with a HUGE turbo that makes 100 HP until it gets to 10000 RPM when it finally has enough exhaust flow to spool the big turbo and suddenly it makes 650 HP at 10000 RPM. compare that with a built LSX that makes 400 HP at 3500 RPM and 600 at 6500 RPM. which would be faster? which would be better to drive?
If you graph my numerical examples, you will see that the LSX is a bigger overall "mountain" than the turbo 4 which straight lines until it goes straight up.
If you compared the two by peak numbers, you might get the impression that the 4 banger is "faster." however, it will not be.
the idea is that the earlier in the RPM range you can get a bigger number, and the longer through the RPM range you can sustain it, the better.
when people say that looking at what is under the curve is more important they are referring to the fact that it is more important to have good power through the whole RPM range rather than just a good peak number. it makes you faster.
an extreme example would be comparing a little 1.5 liter 4 banger with a HUGE turbo that makes 100 HP until it gets to 10000 RPM when it finally has enough exhaust flow to spool the big turbo and suddenly it makes 650 HP at 10000 RPM. compare that with a built LSX that makes 400 HP at 3500 RPM and 600 at 6500 RPM. which would be faster? which would be better to drive?
If you graph my numerical examples, you will see that the LSX is a bigger overall "mountain" than the turbo 4 which straight lines until it goes straight up.
If you compared the two by peak numbers, you might get the impression that the 4 banger is "faster." however, it will not be.
the idea is that the earlier in the RPM range you can get a bigger number, and the longer through the RPM range you can sustain it, the better.
