TwizzleStix. Just ordered Cobb Stage 1 for 2020 SCrew. How do you get sub 5aecond time in 0-60?
The right tune and launch technique. Sport mode, Adv Track OFF, 4Auto, Rear diff locked, brake-boost build to final at WOT for ~ 1 sec, release brake, hold on and keep it pointed straight...
No wheel spin allowed, so make sure the tires are clean and hot. I usually drive several miles at highway speeds (in 4Auto) to get everything up to temp, so there's minimum fluid drag.
If you're using a non GPS-based device, ANY wheel spin is counted as forward motion and shortens the time, so ZERO wheel spin is a must for accurate time. I also recommend running the truck at 60 mph and compare to a GPS navigation device (like Garmin, etc.) to make sure the speedo is accurate as well. You can adjust the tire size with the AP to calibrate the speedo.
A GPS device like the Draggy doesn't care, it measures the actual time in motion vs the actual speed. The Draggy can apply the 1 foot rollout subtraction as well for pretty accurate (less than 1/10 difference) drag strip times.
The OEM setup reads faster than actual, so the 0-60 time will show to be several tenths quicker than actual until you get the speedo accurate. If you do the diameter calculation for the OEM tire 315/70x17, it is 34.36". The actual effective "rolling" diameter is ~32.9". The rolling diameter is less than calculated because the rolling is affected by the sidewall sag (weight on tire) and the tire pressure.
I've found for my particular setup that 32.9" results in the most accurate speedo readings that match both Garmin and Draggy results. All things being equal, increasing the tire diameter value results in increasing the indicated speed, whereas decreasing the tire diameter value results in decreasing the indicated speed.
Note that there are several folks running sub-5 second times on here, but I can't comment on their measurements, setup, or technique.
