Just got my 1st sub 1.9, 60'.
Well, I've been trying to figure it out for the last 5 years and still don't know. My best launches have been where I just rest my foot on the gas pedal and don't push it until I let out the clutch. And I'm not too hard on the clutch either. Pre-reving the engine for an aggressive launch has always given me excessive wheelspin which results in high 60' times, ie. 2.2 to 2.6 secs. I finally popped off a 1.872 using that technique last weekend on my 13.05 run and have no idea what I did right. I've slowly whittled it down from the 2.1's and 2.0's over the last several months into the 1.9's on almost every run now. Now that I can burnout and heat the M/T's better maybe I can be more aggressive but on street tires avoid hammering down until the car is moving good or you'll spin and axle tromp. Preventing wheelspin should give you your best launches.