Subject	Here are some performance equations that might >>>
Posted by	ZUL8TR on January 20, 2004 at 12:19 PM
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In Reply To	Which is better? 1 horse or two horses? posted by AshsZ on January 19, 2004 at 11:25 PM
Message	clarify the use of HP, gearing and 1/4 mile ET and MPH. I found these formulas in a performance article (don't remember the source) some years back. I know all cars are different and there are many variables as noted in the posts above but the factors in front of the equations (from track experience)supposidly take most of that into account and the equations do provide an interesting relation for the most easily obtained parameters like weight, horse power, RPM and gear ratio. Have fun with the results on your own set ups. For 1/4 mile performance: ET = 5.825 x cube root(W/Hp) MPH= 234 / cube root (W/Hp) Combining these equations: ET = 1363/MPH W = weight Hp = Horse power To achieve these ET and MPH values the following overall gear ratio (OGR) is needed to operate the engine at the desired Hp point of the power curve. When I was heavely envolved with 1/4 mile drags we always shot for a little bit higher RPM than the peak Hp RPM for the engine at the end of the 1/4 mile run in final gear of the tranny (not the overdrive gear but the 1:1 tranny gear, 4th in our cars). OGR = D x RPM/(N x MPH) D = Tire diameter (at rest I presume) RPM = engine revolutions per minute ( I guess the torque equation could be replaced here to eliminate RPM and get torque in the equation) N = 340 for manual tranny and 335 for auto tranny (factors from track experience). ZUL8TR in Orlando,FL
Follow Ups	Which is better? 1 horse or two horses? - AshsZ 23:25:09 01/19/04 you think too much Ash, you need to get laid :) (n/m) - hey GotBo0st 23:28:57 01/19/04 Holy shit...im going to bed...*over the head it went* :p (n/m) - michaelkih 23:31:14 01/19/04 Why don't you answer my question below about - MikeH(Twin GT35BB Incon Z) 23:38:46 01/19/04 The difference would be like a drop into the ocean. - AshsZ 23:44:56 01/19/04 Hmm.. Passing thought: If you were to put the MAS element - AshsZ 23:55:45 01/19/04 How's the speed-density thing going? (n/m) - Kenny 00:26:01 01/20/04 Its still just an idea in mind... We made 811RWHP - AshsZ 00:46:43 01/20/04 What method did you use to calculate that? (n/m) - therin (Plum) 09:01:55 01/20/04 Yep - SAHTT 23:43:40 01/19/04 Thanks for the bed-time story. It was a good. (n/m) - bb0ys (Bean-town) 23:49:43 01/19/04 Interesting. Note the proper unit for torque is lb-ft. - SooperZ95 23:55:33 01/19/04 pound foot sounds painful. (n/m) - AshsZ 23:56:54 01/19/04 ditto (n/m) - Scotts94z32 10:30:13 01/20/04 I have a concern: - ALSODAIS 23:56:44 01/19/04 In the water pail example, they both are raising the same - AshsZ 00:06:14 01/20/04 I see: You are referring to the HP at a certain velocity - ALSODAIS 00:21:05 01/20/04 Exachery. And if car #2 were running at 6000RPM and 500TQ, - AshsZ 00:42:40 01/20/04 Hey ash do you play chess???? - rave 00:09:22 01/20/04 Gearing & torque multiplication effects.... - hickersb1 00:13:29 01/20/04 That is true-you are trading off torque for more RPM at the - AshsZ 00:39:11 01/20/04 We're saying the same thing except --> - hickersb1 09:51:11 01/20/04 I see what you mean. It goes without saying that if you - AshsZ 12:19:36 01/20/04 So what your saying is... - liverdamage 00:44:21 01/20/04 gotta modify your statement slightly... - JokerF_15 01:41:39 01/20/04 i am now on the road to ultamate enlightenment (sp) (n/m) - Z_animal 00:45:53 01/20/04 I just realized how stupid i am, thanks - AJ6630 01:20:21 01/20/04 Your a brain ash but you drink to much coffee....... :0 (n/m) - ChrisZNA (Sacto, CA) 01:43:51 01/20/04 God, I love this forum! Good work Ash! ;-) (n/m) - MarTTy4653 02:13:44 01/20/04 The equation "Tq = Hp*5252/rpm" has limited usability - Tredmil 03:28:18 01/20/04 What a hum dum about nothing - Carlos Ramirez 06:56:28 01/20/04 my 2cents here: if you would like to explain to a layman - JC_NS 09:33:32 01/20/04 :) - Rickytl 10:12:19 01/20/04 Theory and reality sometimes differ though. (My rebuttal) - Marshall 10:33:07 01/20/04 Re: Theory and reality sometimes differ though. (My rebuttal) (n/m) - krd 11:35:00 01/20/04 Here are some performance equations that might >>> - ZUL8TR 12:19:14 01/20/04 Everything you said makes sense, but - NytWolf 12:23:29 01/20/04 now for a real experiment... - TagZ 15:07:47 01/20/04
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