What I'm saying is that HP and aero effects are interrelated. Gen 4 cars had a lot of horsepower, twisted sister bodies intended to produce a lot of downforce and side force with low drag, and operated in an era of emerging aerodynamics expertise in Nascar. That last point about aero sophistication is gone forever and can never happen again, although one can attempt to retrieve sorta kinda similar effects by mandating spec bodies and other components that cannot be altered.
Good skill-based racing requires substantial changes in speed that the driver must manage... braking into corners... searching for the razor's edge to maximize mid-corner speed... accelerating off the corner fighting for grip to get the throttle open a fraction earlier than the other guy. The way to achieve this is plenty of power for robust acceleration, and a scarcity of cornering capability due to aero downforce and side force. That's just my opinion, but it's not a completely uneducated opinion.
The fallacy of the NA18D philosophy is that it takes all that away, and offers a leader with a drag penalty pursued by others who can stay close (no drag penalty on them) but they can't pass because they suffer a downforce penalty from dirty air. Everyone's droning around WFO (or very close to it). Straightaway speeds are low because low HP and high drag. But cornering speeds are high because of the high downforce... there is little to no need to lift. The illusion of close racing.
As
@aunty dive often says, aero effects have always existed and always will, at least until we are racing on Mars. He's right, of course. But I believe aero effects can be mitigated to avoid creating an overwhelming advantage for either the leading car or the pursuing car. If total aerodynamic downforce is low, then the penalty of losing 15% of it due to dirty air will also be a low penalty. Also, if aero drag is low, the drag penalty of being the leader will be lower than if drag is high (and I believe the Next Gen car is very high drag).
I postulate that Next Gen is high drag by observing that fall 2021 test at Charlotte. With the familiar 550 HP, the new car circulated at or close to WFO and was way slower than the year before with the same power... something like 3 seconds slower IIRC. What could cause that, other than high drag? In desperation, Nascar had some teams test radically smaller spoilers for less drag, while other teams tested 670 HP to power through the drag. Finally, Nascar adopted both... smaller spoilers and more horsepower... and still were slower than he year before but by a lesser amount. I don't know why Next Gen was designed with so much more drag. Nascar has never addressed the topic.
So is a very drag-y Next Gen car with 670 HP really a more potent piece than last year's Gen 6 at 550 HP? No, I don't think it is. There is more off-throttle time, and this is absolutely crucial to the improved quality of racing. I think that comes from the lower downforce due to smaller spoiler, rather than from the extra ponies. I'd definitely like to see more power to get away from the momentum racing. More power. Or less drag. Or both.
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