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In another thread I had posted where I took some info provided on this forum and elsewhere and calculated what I think is pretty close the coefficient of lift for the ZR1 with the ZTK package as well as the Stage 1, 2, and 3 aero configurations on the Z06. Just for fun I decided to create a match channel in Pi Toolbox to graphically show the effective downforce over the course of a lap at VIR. Now one big caveat is that I used the same speed trace for all 4 traces and that speed trace was from a lap in the ZR1. In a slower car the speeds would be lower and so would the downforce numbers but this gives you a straight comparison between the aero packages on the C7 widebody. I also inverted the values so downforce is positive and lift is negative. The black line was just there to show you where zero lift is.
Is there any way to quantify the speeds at which the downforce levels were present? In other words, using the down force peak at 12500 feet, what was the speed of the vehicle at that point?
I really wish I had even a scintilla of knowledge on how to properly use the toolbox. Thank you.
I'll post about graph this evening with a speed trace but you're roughly running from 40-170 MPH.
From Road and Track article on ZR1: ...That splitter also lacks the carbon-fiber end caps present on the big-wing car’s. The result is a drag coefficient on the small-wing ZR1 that’s about the same as the Stage 1 Z06’s but with marginal downforce rather than lift.
Wow that I did not know. Now you got me wondering why they put it on the cars. Cool info!
I should clarify. The extra stage 1 aero pieces themselves don't create lift, they reduce lift. My point was that most road cars have lift at speed and so while these parts reduce lift it's still overall positive.
I should clarify. The extra stage 1 aero pieces themselves don't create lift, they reduce lift. My point was that most road cars have lift at speed and so while these parts reduce lift it's still overall positive.
Is there any way to quantify the speeds at which the downforce levels were present? In other words, using the down force peak at 12500 feet, what was the speed of the vehicle at that point?
I really wish I had even a scintilla of knowledge on how to properly use the toolbox. Thank you.
Last edited by Bullet Tooth; 04-25-2019 at 09:28 AM.
Keep in mind, the shape of a car is roughly that of a wing. The air going over the top of the car travels a longer distance than the air under the car(similar to wing on an airplane) and meets again at the rear of the car. This creates a low pressure zone over the top of the car, (lift) so with no other devices to offset that, a Corvette or most other car will have negative downforce as speed increases. This is offset by mechanical grip caused by the gravitational force due to the cars weight and add on aero devices like Splitters, front under reverse wing and BIG A** upside down rear wing.
Last edited by Rinaldo Catria; 04-25-2019 at 09:54 AM.
Is there any way to quantify the speeds at which the downforce levels were present? In other words, using the down force peak at 12500 feet, what was the speed of the vehicle at that point?
I really wish I had even a scintilla of knowledge on how to properly use the toolbox. Thank you.
I'll post about graph this evening with a speed trace but you're roughly running from 40-170 MPH.
This is the kind of stuff that I really enjoy. Just out of curiosity, where did you get your data from? Also any data showing the difference in downforce when changing the angle for the rear ZTK wing?
This is the kind of stuff that I really enjoy. Just out of curiosity, where did you get your data from? Also any data showing the difference in downforce when changing the angle for the rear ZTK wing?
Someone posted on the forum the downforce for the various Z06 aero levels at 150 MPH from a presentation Tadge did at the Bash. Then I took the the "950 lbs of downforce at top speed" claim GM had made repeatedly and the best I could find the top speed for a ZTK car was 202 MPH. From there it's just math
I should clarify. The extra stage 1 aero pieces themselves don't create lift, they reduce lift. My point was that most road cars have lift at speed and so while these parts reduce lift it's still overall positive.
I wonder what the difference between lift is at the point you have a number for, with no aero at all and level 1. In other words how much is the level 1 helping compared to no aero at all? The down force with the high wing is amazing. I also wonder how the GTLM C7R wings compare to the ZR1 high wing.
It's pretty nice, but I think there's too much approximation here. From the calculation above, you seem to be taking squared of the speed ratio to calculate down force at different speeds, but you can't apply that formula on overall lift/down force, but rather on its components (i.e. how the wing down force scales, while how the natural lift sans the wing also scales up, etc.).
Even if you do that, it will still be gross approximation as we don't know the interactions of different air elements.
Anyhow, it'd be less educational, but sticking with wing or a splitter's own performance might be a bit more accurate, and dare I say it, more acceptable : )
04-24-2019, 06:35 PM
[GRAPH] Effects of downforce
