Rollout at SGMP

Rollins_2241 · 03-08-2011, 04:03 PM

Downtrack doesn't matter, it's the crown and position of the groove at the starting line.

NHRA sets the beam height the same everywhere (1 + 9/16" I think.) and tests it with a 22" front tire template so that the "on paper" rollout of about 11" is established. Exactly how they do that is better explained by Jeff Foster.

But that doesn't account for where your car is in a real time trial. You should stage "in the groove" but the groove is not the same distance from the infrareds at each track, nor is it the same throughout a weekend. None of this matters if the track is perfectly level relative to the beams, but most tracks are built with varying degrees of "crown" for drainage.

The bottom line is that where you stage "east to west" as well as "north to south" when staging can have an impact on rollout and reaction time, and it is impossible to standardize conditions totally from track to track. And of course, we haven't even talked about the human element.

03-08-2011, 04:03 PM	#5
Rollins_2241 Member Join Date: Nov 2007 Location: Tallahassee, FL Posts: 170 Likes: 0 Liked 0 Times in 0 Posts	Re: Rollout at SGMP Downtrack doesn't matter, it's the crown and position of the groove at the starting line. NHRA sets the beam height the same everywhere (1 + 9/16" I think.) and tests it with a 22" front tire template so that the "on paper" rollout of about 11" is established. Exactly how they do that is better explained by Jeff Foster. But that doesn't account for where your car is in a real time trial. You should stage "in the groove" but the groove is not the same distance from the infrareds at each track, nor is it the same throughout a weekend. None of this matters if the track is perfectly level relative to the beams, but most tracks are built with varying degrees of "crown" for drainage. The bottom line is that where you stage "east to west" as well as "north to south" when staging can have an impact on rollout and reaction time, and it is impossible to standardize conditions totally from track to track. And of course, we haven't even talked about the human element.