So I just did a pretty good 0 to 60 run in the vette and the car cluster clocked me at 2.9 but the PDR says 3.2. Ill take both lol but which do yall think is the more accurate time?

 

Neither the Dashboard time nor the PDR video are accurate. I have found that they are understated by 0.136 to 0.221 seconds.

I recommend three more accurate timing options:

1. Buy a Dragy DRG70-U for about $159
2. If you have a PC, download the PI Toolbox software and you can calculate a more accurate 0-60 time, but it is a tedious process.
3. Go to a Drag Strip with timers.

The Dashboard and PDR Video displayed times are closer to the 0-60 1-foot rollout times but still not accurate and are almost always understated.

There are 2 types of 0-60 times.

1. A 1-foot Rollout. The 1-foot Rollout times are what is used by Motor Trend and Car and Driver and many drag strips. "Rollout or rollout allowance in North-American drag racing is the difference between actual acceleration time and measured acceleration time. For the published 0 to 60 mph acceleration time in North America, a rolling start is used, beginning 1 foot after the initial standing start position." Basically, the timer does not start until the car has moved 1-foot.
2. 0-60 from the standing start without the 1-foot rollout.

How much are the Dashboard and PDR's Video time off?
I have found statistically that on average you need to add somewhere between 0.144 and 0.221 seconds to the Dashboard time, and somewhere between 0.136 and 0.211 seconds to the PDR Video displayed time to come closer to the actual 0-60 with 1-ft rollout time.

The PI TOOLBOX and COSWORTH TOOLBOX SOFTWARE
The PI Toolbox (download on a PC) or the Cosworth Toolbox software (download on a PC) processes the same PDR Video mp4 file. That file has tons of data in it relating to your car. Oddly the numbers displayed on the PDR video do not match the PI Toolbox numbers that you can calculate through much effort. The Cosworth Toolbox will readily give you the 0-60 time with NO rollout. This number will 0.36 to 0.38 seconds slower than your Dashboard and PDR video displayed times. If you only care about the 0-60 time with NO rollout then you can trust the Cosworth Toolbox provided number. I have confirmed the accuracy of this number multiple times against the PI Toolbox data looking at the run at a detailed level of 1/100th of a second from the time the car moves until it hits 60mph. The Cosworth tool will not determine if you did your run down hill with a greater slope of 1%. You can calculate this using the PI Toolbox software by looking at the altitude data for the1/100th of a second measurement at the start of the Launch to the 60 mph time.

THE DRAGY DRG70-U
To make things easy for you, buy a Dragy for about $159. It validates your times base on being under a 1% slope and when it has acquired enough (> 26) satellites to insure accuracy. I have seen the Dragy give a false or inconsistent slope reported based on multiple runs on that exact same road starting at the exact same spot.

Bottom Line:
If not on a "Drag Strip", I consider a valid, run only if it is confirmed by both the PI Toolbox processed PDR file and the Dragy device. Many will simply rely on the Dragy numbers (and that is fine).

TIPS for good Launches based on my experiences:

1. Run with 2 to 4 gallons of gas in the tank. That will save about 100 lbs. when compared to a full tank.
2. Do the run without a passenger. Keep the weight down.
3. Basically you want low temperature, high barometric temperature, and low humidity and your actual altitude as close to sea level as possible. This helps reduce the Density Altitude (DA) number. The lower the number the better the conditions. "DA is essentially the adjusted elevation at which the car is racing based on atmospheric conditions like temperature, barometric pressure, and humidity. Higher altitudes can have less dense air, which affects a car’s engine performance because there’s less oxygen for fuel combustion."
4. Choose a level road or slope is less than 1%.
5. Make your run with tire temperatures in the normal range, not cool.
6. Some suggest a tire pressure of 28 lbs is good. I had success between 31 and 32psi with warmed tires.
7. Do your Launch in Sport mode. Many have found this to provide the best for low tire spin.
8. If you consistently experience tire spin, then find another location with a better road surface. The surface will depend a bit on your tires (Summer vs 4 season).
9. Stop the PRD and Restart your PDR just before your launch. (15 seconds or less before). Stop the PRD right after your run. This is important if processing the PDR's mp4 file in a software tool. This provides the best access to data numbers related to the actual run. Fuel level, Car measurements relating to current Tires, Outside temperatures, Intake temp., Coolant temp, Oil Temp, G-Forces, etc. If you have multiple launches in the same PDR file, then it will only report the fastest 0-60 (No Rollout) time in the Cosworth Toolbox software.

Here is a run in a C8 HTC non-Z51 Stingray running 4-season tires and rated at 3.0 seconds by Car and Driver. The Launch was with two passengers and a half of tank of gas. Additional stats on the launch are presented in the YouTube description of the video. I believe I mixed up the Dragy screenshot with another previous launch, so they are off by 0.01 seconds for the 1-ft rollout. The two runs were almost identical.

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Here is another Launch with the driver only. All timers with a 1-foot rollout from various sources are 3.0 and lower. Oddly the Dashboard timer is the highest on this run, when on average it is always lower. Again I feel these are good numbers for C8 Non-Z51 Stingray Hard Top.

 

Awesome and thanks. I was on about 1/2 tank gas with warm tires and used launch control so Im pretty happy with a 3.0 ish run, which is awesome. Still much faster than my C7. I do this just for fun and its my daily driver so just having some fun in it.

 

What's involved in this that makes it a tedious process?

 

Unlike the Dragy, the PI Toolbox does not outright give you the timings for 0-30mph, 0-60 1-ft, 0-60mph, or a 60ft time.
You have to step through the data for the run for every 1/100th of a second to determine the following:

1. Determine the time since you started the PRD and the last moment in the run where Speed and Distance are zero. (The Start Time of the run). The next 1/100th moment the distance and time will be above zero
2. Step through each 1/100th sec until the moment before the distance reaches 1 foot.
   1. At that moment in time, Record the elapsed time,
   2. record the distance (prior to the 1-foot).
   3. Step one more 1/100th and record the distance that is greater than 1 foot.
   4. Use a calculation to determine the exact moment (time) of the 1-foot distance based on step 2.2 and Step 2.3.
3. Repeat similar steps to get the 0-30 mph moment as follows
   1. Record the time just prior to hitting 30mph
   2. Record the distance just prior to hitting 30mph
   3. Step to the next 1/100th as you just past the 30mph mark.
   4. Record the distance
   5. Use a calculation to determine the exact moment in time that 30mph was hit. (Sometime greater than what was recorded in step 3.1 and the next 1/100th of a second.
4. For other measurement like the 60 foot time, or time to 0-60mph and 0-60mph with 1-ft rollout, Repeat the same process in in step 3 but for those moments.

I use a spreadsheet to do the calculations to determine exact moments that are a fraction of 1/100th of a second (1/1000th) for the above process.

Alternatively, I could try to figure out how the PDR Video file stores its raw data in the mp4 file and attempt to write a program to process the data and do the calculations for timings as I am doing manually.

The Cosworth Tool does accurately calculate the 0-60 (without a 1-ft rollout), but that is it. I know it is accurate because it matches up with my numbers for 0-60 to within a 1/1000 of a second calculated from my process with the PI Toolbox. Cosworth does round up or down since it only displays the number with 2 decimals. Note both the Cosworth Toolbox and the PI Toolbox are both owned by Cosworth Electronics, Ltd.

I am not sure if there is a paid Pro version of the Cosworth or PI tools that could provide the numbers. The other thing is that I feel that both the Cosworth toolbox and PI Toolbox takes time to understand and to setup to the point where you can step through the run for each 1/100th of a second.

My whole point about discussing these tools is to let someone know it is possible to better determine 0-60 times. There are other benefits of using the PI Toolbox to determine your exact Fuel level and specific tire measurement and Intake measurement. As stated earlier in my previous post that it is best to stop the PRD prior to doing the Launch and restart it as you are stopped and before you start the launch. This makes it easier to find the starting point and does not mix multiple launches in the same PDR file.

Based on the above, I will repeat my comment that it is easier to just pay the $159 or so for a Dragy DRG70-U that can be customized to record all of the above and more and save you time.

I will disclose that I am new to "Launches" and just want to share my knowledge gained in the last few months. I have reached out on forums to get details about this topic before with little specific feedback so I am trying to help others who may care about 0-60 times and what can be obtained from the PI Toolbox and Cosworth Toolbox.
Anyone who want's even more details about those tools message me and I can share my setup of the PI tool since it is not very intuitive to do what I am doing. The tools are more geared toward analyzing track events and repeated lap analysis.