Quote:
Originally Posted by onfireX5
I've raced for 46 years on NHRA, IHRA and non sanctioned tracks.Never on one that was perfectly level in elevation. The NHRA spec to be certified as an NHRA track, and must be proven with an engineer level, etc process is +1% to -1%. Within that range , NHRA will cert the track. Bristol, for example is almost +1% uphill. Rockingham is down less than 1. After slope, proceed to the accuracy of the track testing equipment and more importantly , set up location. Some have more rollout than others to give better ET's . Some move the timing beams a bit to shorten the track. One track I unloaded at, I knew something was wrong with my car. It was running 0.30 quicker and 5mph slower off the trailer. That big of a jump worried me and I started to load back up. Track starter came over ....discussion....oh, we have the end beams moved in for this race....track is shorter....so, it's all relative . Some tracks go downhill and back uphill...
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The question isn't whether some sanctioned Strips are uphill/downhill slope. That's a given across global terrain.
But, what those tracks do have are near perfect slope accuracy and precision 'within their set grade', even if the exact value is unknown, which cannot be debated. Unless a track does a reconstruction or major track surface revision, those values are set (notwithstanding earthquake etc terrain upheavals which may alter the grade).
And ability to verify results is also key. For example, you indicated Rockingham has a negative slope. Even within the constraints of GoogleEarth's altitude accuracy and precision data, I can see that Rockingham Dragway in NC has an almost due West orientation of ~268.96 degrees, and the altitudes indicate start at 434ft, 1/8mile at 428ft, and 1/4mile at 420ft. So indeed about -1% give or take. And Bristol TN Dragway which you mention is almost 1% uphill - yes, easy to confirm by GoogleEarth which shows altitudes as 1479ft start, 1/8mile at 1482 and 1/4mile at 1491ft (and a near true NE orientation of 43.29 degrees).
All easily verifiable, not subject to change within 2" over the next 25 years unless a resurfacing project or major landshift occurs.
Completely different situation in which Submitter A shows he/she did a run using a satellite measurement system starting at an unknown location, on an ill-defined surface (although not all preps are the same at tracks, one should agree that it is more defined than an unknown surface run anywhere across the globe). Unless it is known that someone performed the run at 'Main St & E. Maple St, starting by the streetlight next to the Post Office, running 'x' direction, and that it is known to be level...'. And I still wouldn't have any idea of the surface composition. So how can I use that performance data to compare to mine?
I own Dragy, and I use Dragy, and I appreciate what it offers, and at a sanctioned Strip I am comfortable using it's value to replace an errant or missing data point, but I'm not ready to equate such data as reference.