Quote:
Originally Posted by ZDan
You shouldn't just go with PEAK power and PEAK torque alone.
The earlier engine sacrifices power and torque throughout the range for a couple of peaks over limited rpm ranges. Likely the new engine's cams have a bit less duration and overlap, hence broader less peaky power curve.
At hp *peak* of 7000rpm, the new 2.4 indeed only makes 11% more power vs. the 2.0 and not 20% more as displacement would suggest, all else equal. And the new 2.4's *peak* torque is only 18% more vs. the old 2.0's *peak* torque (close to but not quite 20%).
However, if you look at power and torque at the old engine's torque dip around 4000rpm, the new engine is making about 38% more power and torque there.
On average you're going to see ~20% more power and torque throughout the powerband. The peaks have been rounded off a bit, but the midrange trough has been massively filled-in. For sure they could have kept the same amount of peakiness and same power/liter, but at the expense of midrange. I would bet that actual overall performance is the same, but without the lull in the midrange.
Here's my plot of rwhp/torque of 2022 (scaled based on the dashboard readout) vs. 2017:
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Yep, too many people focus on peak numbers and ignore the "area under the curve."
That's why racing sanctioning bodies like NASA now base your pw/weight ratio on average power vs peak power.
Guys were looking for specific peak power to weight, and then over-building the engines and tuning them to produce that peak number for a few a much wider powerband vs a quick jump to it at the peak.
Which the made the cars significantly faster. You used to be able to see Miata's, particularly the guys out of 949 Racing, who had cars that made power from 5200-7500 RPMS.