[apk919]

Originally Posted by Bleu Omdurman

Hey guys,

This post is directed at those that track their cars often and have made a couple of changes to the car, and noted the difference, if any.

As I posted in the "another physics question" thread, I am building a decision model to aid in picking the optimal modifcation set, given a certain budget. It uses Microsoft Solver. The objective function is to minimize lap time. In other words, modifications are decided upon based on their effect on laptime as a function of cost.

Three of my decision variables that effect laptime are:

1) Required lbs lost to drop 1 second of laptime.
2) Required HP gain to drop 1 second of laptime.
3) Required lbs of downforce to drop 1 second of laptime.

Clearly, what track you are minimizing laptime on, is important. That is why the three above are variables and not constants.

Here is a recommended format for your reply.

BWR S/C +53 hp, 1 second gain at Leguna Seca
CF Diffuser, -10lbs weight, +5lbs downforce, 8 tenths at Sebring

anything helps.

BTW, the numbers I am using now are 100 lbs/sec weight, 15hp/sec, 20lbs/sec downforce

Sounds like an interesting project; I've written software models for other fields, never for a car. Actually started in HS writing a mathematical model for the performance envelope of an F-14.

Which brings me to a question: are you adding in the effect of increased aero drag with the increased aero downforce? Also, are you taking into consideration that aero lift/drag has a square law relationship with speed?