Sorry for the double post, but here is a good example of how important the on-board computers are, as well as having the ability to graph it out visually. On this particular day, we only got one time shot, so it was exceptionally hard to dial the car. Ben was on a streak of red lights, so I decided to back the idle down a bit to slow the car's reaction - yet have him leave on the same spot on the tree.
This computer allows you to overlay two runs to compare, the red line is rpm. Notice the lower starting point on the left with one of the red lines, it was lower than I wanted it to be - but once he lites the top bulb I can't touch the car. These 12.90 carbs can vary their idle a lot, thus he left at ~3650 rpm vs the prior run of ~4000 rpm. The car slowed by 1.5 tenths, and his .014 light was not enough to compensate the other car's .130 lite. This is the hair pulling cycle of 12.90, but I could not blame the entire deterioration on the starting line rpm.
When perplexed, ask the driver! Ben states that he might have lifted or pedaled - normally this is good when you tree the other driver, but he would not have known that yet. So, why? He wasn't sure what he did.... I'm befuddled, there was no wind, no tire spin, engine didn't break up.... I pull the laptop outta the truck, download the runs to the drive and upload them - to find this!:
Notice where one of the red lines drops off significantly sooner than the other. Ben was right, he did lift - unconsciencously, as he was looking around for the other car! Good stuff to know, can't argue the data. [img]<<GRAEMLIN_URL>>/wink.gif[/img]
Another point, this kid has sure grown in a little over a year! The car is up on the stand in the most recent pic, so you have to add about 4 inches!
