JSG1901 Posted November 20, 2014 Share Posted November 20, 2014 Proposed change Change from a a fixed dyno variance to a percentage based difference. Reason The error in a dyno due to calibration, etc. is unlikely to be a fixed number across the entire range of measurement. If the weight of the drum, friction factors, load cell calibration, etc are off, the calculations done by the dyno software will multiplicative in error not additive. By changing to a percentage of error, it should be more accurate to the actual variance experienced by the range of cars. Looking at the typical HP ranges for GTS1 through GTS5 cars, a 4 hp variance is as much as 2.5% and as little as 0.9% of a declared number. With the fixed 4 hp, drivers at the lower RPM ranges might be incented to push the limit whereas a driver with a high HP car needs to have a larger cushion. Proposed wording To allow a small safety margin for dyno variance, the peak HP number (or average of peak HP/TQ for those cars it applies to) will be multiplied by 0.98 (number up for discussion). However, if a car does not meet the minimum weight listed on the certification sheet, the forgiveness cannot be used to arrive at a compliant number. Link to comment Share on other sites More sharing options...
flink Posted November 20, 2014 Share Posted November 20, 2014 Yes, that makes perfect sense. We should do the same with the various power-to-weight penalties as well. Penalizing a sequential tranny with 0.2 lbs/hp is a 1% penalty in GTS1 and a 2.7% penalty in GTS5, which doesn't make sense. It too should be a percentage. Link to comment Share on other sites More sharing options...
MPower6er Posted November 20, 2014 Share Posted November 20, 2014 I think this is a reasonable proposal; would support. Link to comment Share on other sites More sharing options...
Brad Waite Posted November 20, 2014 Share Posted November 20, 2014 I vote YES Link to comment Share on other sites More sharing options...
jvanhouten Posted November 20, 2014 Share Posted November 20, 2014 agreed. Link to comment Share on other sites More sharing options...
scottbm3 Posted November 20, 2014 Share Posted November 20, 2014 Would like to know how we come up with the percentage number, but that said I'm fine with it. -Scott B. Link to comment Share on other sites More sharing options...
cash7c3 Posted November 21, 2014 Share Posted November 21, 2014 For. Link to comment Share on other sites More sharing options...
J Smith Posted November 22, 2014 Share Posted November 22, 2014 Yes. This make sense! And I think using the .98 as the factor is pretty darn close, but I may like .985 better to keep things a little tighter. Link to comment Share on other sites More sharing options...
CARVAL Motorsports Posted November 22, 2014 Share Posted November 22, 2014 Is this correct: declared 100hp - 102 good on dyno 200hp - 204 good 300hp - 306 good 400hp - 408 good 500hp - 510 good I fear that the lower hp cars could fail at the dyno disproportionately to the higher hp cars. Food for thought. Link to comment Share on other sites More sharing options...
peter*g Posted November 22, 2014 Share Posted November 22, 2014 I agree, although I wonder why we would allow any more than 1%. Link to comment Share on other sites More sharing options...
Greg Smith Posted November 26, 2014 Share Posted November 26, 2014 For. Link to comment Share on other sites More sharing options...
Luke P. Posted November 26, 2014 Share Posted November 26, 2014 For. Link to comment Share on other sites More sharing options...
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