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Originally Posted by 86TOYO2k17
My diy rear seat delete is significantly less noise then stock seat/trunk junk. Rear seat -32lbs then I put 8lbs of sound insulation/cardboard/chloroplast/carpet back in.
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That is cool! But still, -24 lb. or -32 lb. just isn't going to make any difference as far as seat-of-pants feel, and barely any difference in measured acceleration or lap times.
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And yes drag reduction won’t make a huge difference in 0-60 and the 1/4th when trap speeds are around 90mph as aero doesn’t make a noticeable difference until about 60mph and a substantial difference until about 100mph. Aero is Great for better mpg, Hwy pulls, and faster tracks.
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It will affect mpg a lot more than acceleration or lap time performance. Even there the difference will be quite small.
I modded the performance analysis spreadsheet I had made for my FD's Texas Mile run to simulate my stock-drivetrain '17 BRZ. I looked at what the elapsed time and max speed would be after a straight at full throttle after exiting 60mph and 80mph turns:
cD = 0.31: 60mph + 1500ft = 11.97 seconds @ 104.1mph
cD = 0.28: 60mph + 1500ft = 11.95 seconds @ 104.8 mph
10% lower cD => 0.02seconds quicker
cD = 0.31: 80mph + 2300ft = 15.26 seconds @ 120.1 mph
cD = 0.28: 80mph + 2300ft = 15.17 seconds @ 121.2 mph
10% lower cD => 0.09seconds quicker
Optimistically you *might* see as much as a 0.25 second lap time reduction at a faster track like Watkins Glen from a 10% reduction in drag coefficient.
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Also most of the drag reduction for this car also adds downforce.
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Decreasing lift/increasing downforce will influence laptimes much more so than drag coefficient.
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But 0-60 and 1/4 is a horrible way to measure auto 86s acceleration. When almost no one cares about stop light/off the line speed. Think 60-120 is a better comparison for real world applications.
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For 60mph - 120 mph times for 17+ BRZ, I get:
cD 0.31 60-120 = 19.50 seconds
cD 0.28 60-120 = 18.74 seconds
10% lower drag = 0.76 seconds or 0.4% quicker 60-120 mph.
Background: I did performance analysis at an electric vehicle startup in the 2000s/early 2010s. Developed spreadsheet for 500hp FD that predicted its standing mile performance within <1mph, predicted = 184.2mph, actual = 184.8mph