brkntrxn Posted December 26, 2010 Share Posted December 26, 2010 (edited) After not finding any definitive answers (at least that I plainly understood) in the following sources, I am going to post up my thoughts/question in a new thread: TT Rules: http://www.nasaproracing.com/rules/time_trial_rules.pdf Various threads I searched: posting.php?mode=quote&f=2&t=36686&p=270519 viewtopic.php?f=2&t=30832&hilit=limit+tta+hp%2Fwt viewtopic.php?f=2&t=31334&hilit=limit+tta+hp%2Fwt viewtopic.php?f=2&t=32145&hilit=limit+tta+hp%2Fwt viewtopic.php?f=2&t=35820&hilit=limit+tta+hp%2Fwt viewtopic.php?f=2&t=37240&hilit=limit+tta+hp%2Fwt viewtopic.php?f=2&t=37795&hilit=limit+tta+hp%2Fwt viewtopic.php?f=2&t=38419&hilit=limit+tta+hp%2Fwt viewtopic.php?f=2&t=38401&hilit=limit+tta+hp%2Fwt ..... Plus I get .4 for running 275s, but have to add back .1 due to the lighter min comp weight. So.... at the end of the day I can be at 8.4:1. 3118/361 = 8.64. Max power at min comp weight is 370 so I've got some margin for error there. Furthermore I'm 230lbs, figure 240-250 w/ my helmet and gear on. So my 2840lb car = 3085 w/ me in it, and figure it could hold another 8 gallons of fuel to be full 8 @ 6.6 per = 53. So 3085 + 53 = 3138 when full of fuel which is legal.... I just have to keep it full of fuel. I will probably add 20-30lbs to give myself some margin. .... base weight for a C5 Z06 is 3118 and the car is TTA* I built the car around being able to run A6s so the points are as follows: TTA* - 7 pts A6s - 13 - 4 (for being 275s) = 9 pts T1 swaybars - 2 pts ATI super damper - 1 pt ------------------------------------- Total = 19 pts Min comp weight is 3118, but I have to take .1 back due to the overall low weight based on the TTA-TTF tables which are different than the TTS/TTU/TTR tables. So again I get .4 back for my small tires but give back .1 so I get a net .3 which lets me run 8.4:1 vs. 8.7:1. It's all legit the way it's setup. Why can't this example be in the TT Rules? The examples given in Appendix C do not illustrate how a car can be under the class hp/wt limit and still be legal. The setup described above (running smaller tires than the class size) is a very common situation for the top C5Z06 cars running TTA. In layman's terms in a simplistic example disregarding variance buffers, it shows that a C5Z06 with 19 or less points can run a 275 tire at minimum weight of 3118lbs and have 371rwhp on a DynoJet and stay in TTA. Here is the math 8.7 - .4 + .1 = 8.4 and then 3118 / 8.4 = 371rwhp After pulling some weight out of my car this winter, I can be at minimum TTA C5Z06 weight running on fumes. I have spent a LOT of hours pouring over the TT rules and searching this forum to figure out my horsepower limit prior to getting a tune in January. Unless I am seriously wrong (and Brian's example is also incorrect), I am going to aim for 365rwhp and use fuel to keep me around 3130lbs and have an 8.57 hp/wt ratio. Any input? -Kevin (spending all this money to run for 3rd place) Edit: to correct numbers per Greg's post Edited December 26, 2010 by Guest Quote Link to comment Share on other sites More sharing options...
kbrew8991 Posted December 26, 2010 Share Posted December 26, 2010 people are quoting hp/weight in different ways so that's where the confusion comes from. What matters at the end of the day is the ADJUSTED hp/weight (I shall dub this AHW). The adjustments for one car that put it at 8.70 AHW might be such that its actual hp/weight is much lower than 8.70. Still legal per the adjustments to get to AHW which is what matters. Another car's adjustments might be such that it's actual hp/weight is much higher than 8.70 but when you convert it over to AHW its right at the limit. Quote Link to comment Share on other sites More sharing options...
National Staff Greg G. Posted December 26, 2010 National Staff Share Posted December 26, 2010 Your final numbers are correct, but where you put 8.3:1, you meant 8.4:1. 8.7-.4 +.1 = 8.4:1 Quote Link to comment Share on other sites More sharing options...
brkntrxn Posted December 26, 2010 Author Share Posted December 26, 2010 Greg, Thanks. I corrected the original post and I appreciate your quick confirmation. Ken, I agree the confusion (for me anyway) comes from the way the numbers are interpreted and posted. Math is math and it depends on the specific variable the person is seeking. Most people seem to look at it in this direction and I guess this was causing my uncertainty. For my car, if I have weight of 3130lbs and horsepower of 371, then I would have a hp/wt ratio of 8.43. Add .4 for running 275 tires and I am at 8.83. Then subtract .1 for being between 3100 and 3150lbs and my final ratio is at 8.73 (legal). -Kevin Quote Link to comment Share on other sites More sharing options...
drivinhardz06 Posted December 27, 2010 Share Posted December 27, 2010 For my car, if I have weight of 3130lbs and horsepower of 371, then I would have a hp/wt ratio of 8.43. Add .4 for running 275 tires and I am at 8.83. Then subtract .1 for being between 3100 and 3150lbs and my final ratio is at 8.73 (legal). it's fun finding the sweet spot. 21+ more lbs added to the rear will help your F/R split (ie, 3151+ lb), and give you .05 back on the adjustment (more power). always fun playing with the sandbox parameters NASA gives you to see what's fastest. when you try something and go the wrong direction, it's obvious (see CMP Nov for exhibit one) lol Quote Link to comment Share on other sites More sharing options...
MSP608 Posted December 28, 2010 Share Posted December 28, 2010 What did you do different in November? Quote Link to comment Share on other sites More sharing options...
drivinhardz06 Posted December 28, 2010 Share Posted December 28, 2010 What did you do different in November? got beat like a drum Quote Link to comment Share on other sites More sharing options...
boomn29 Posted January 31, 2011 Share Posted January 31, 2011 Greg, Thanks. I corrected the original post and I appreciate your quick confirmation. For my car, if I have weight of 3130lbs and horsepower of 371, then I would have a hp/wt ratio of 8.43. Add .4 for running 275 tires and I am at 8.83. Then subtract .1 for being between 3100 and 3150lbs and my final ratio is at 8.73 (legal). -Kevin I believe some of the numbers changes for 2011? I was doing some calcs with the new 2011 tables and using this thread as a reference. For this example I'm getting: 3130/371 = 8.437 + .4 (275 tires) - .15 (weight) = 8.687 --> NOT legal The -.15 is for begin between 3100 and 3149 lbs. Quote Link to comment Share on other sites More sharing options...
MSP608 Posted February 1, 2011 Share Posted February 1, 2011 I think you're reading it wrong. It says... Competition Weight: Equal to or Less than: meaning 3150 lbs down to 3101, you adjust 0.1 Quote Link to comment Share on other sites More sharing options...
National Staff Greg G. Posted February 1, 2011 National Staff Share Posted February 1, 2011 right Quote Link to comment Share on other sites More sharing options...
boomn29 Posted February 1, 2011 Share Posted February 1, 2011 I think you're reading it wrong. It says... Competition Weight: Equal to or Less than: meaning 3150 lbs down to 3101, you adjust 0.1 right Thx. Maybe it's a left-brain; right-brain thing but those statements have never made sense to me. I do like on the TTS/R/U form, they have the actual ranges listed out. That eliminates any confusion or interpretation for sure: - 3150-3051 lbs -0.05 - 3050-2951 lbs -0.1 - 2950-2851 lbs -0.15 Quote Link to comment Share on other sites More sharing options...
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