The NHRA SRAC is seeking input from active Comp competitors regarding a possible change to the current altitude correction factoring system
January 31, 2009 by Curator
Filed under Division IV News
The NHRA Sportsman Rules Committee is seeking input from active Competition Eliminator competitors regarding a possible change to the current altitude correction factoring system.
The SRAC Competition Committee had requested NHRA review the altitude correction factoring format used in Competition eliminator. The current altitude factoring system dates back to the early 60’s and was based on tables in aircraft engine manuals that described power loss of engines at altitude. The system has been modified a couple of times since, but never took into account changing engine and driveline combinations to adapt to various track elevations.
Following an extensive review and analysis of runs at altitude factored tracks during the 2007 and 2008 seasons a new Altitude Performance Ratio is being evaluated for implementation. Factors such as engine/cylinder head port sizes/valve sizes, barometer and moisture content will continue to have different effects on the performance of different class combinations.
Racers may submit their comments to rpark@nhra.com by February 9, 2009. Your name and Comp Eliminator Competition Number is required to be included with your comments.
Below is a “draft” of proposed changes to the factoring system: This review is intended only for Competition Eliminator.
| Track (elevation) | Factor | Performance Ratio Calculation |
| Denver (5800’) | 1.0633 x Sea Level Index – .06 seconds | |
| Half-factor | (1.0633 +1) x .5 x Sea Level Index -.03 seconds | |
| Fallon (4000’) | 1.0404 x Sea Level Index – .04 seconds | |
| Half-factor | (1.0404 +1) x .5 x Sea Level Index -.02 seconds | |
| Acton (3700’) | 1.0367 x Sea Level Index – .04 seconds | |
| Half-factor | (1.0367 +1) x .5 x Sea Level Index -.02 seconds | |
| Tucson (3000’) | 1.0281 x Sea Level Index – .04 seconds | |
| Half-factor | (1.0281 +1) x .5 x Sea Level Index -.02 seconds | |
| Boise (2700’) | 1.0245 x Sea Level Index – .03 seconds | |
| Half-factor | (1.0245 +1) x .5 x Sea Level Index -.02 seconds | |
| Las Vegas (2100’) | 1.0173 x Sea Level Index – .03 seconds | |
| Half-factor | (1.0173 +1) x .52 x Sea Level Index -.02 seconds | |
| Great Bend (1900’) | 1.0149 x Sea Level Index – .03 seconds | |
| Half-factor | (1.0149 +1) x .5 x Sea Level Index -.02 seconds |
Supercharged, turbocharged, or nitrous-oxide Comp Eliminator vehicles (i.e. AA/A, AA/AM, AA/AT, BB/A, BB/AM, BB/AT, CC/A, CC/AT, DD/AT, AA/AF, BB/AF, H/D, and I/D) use half factor.
