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+--- Thread: New PPF Formula? (/showthread.php?tid=3242)
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- arena - 05-08-2012
Hi guys, it's your fearless leader here, Jon.
I've been working on the PPF formula today that we have been using for the past few seasons. It's a very complex formula that is designed to equalize the performance of all the different cars, that we got from the Maverick PCA region. The problem is, that this equation is built into a Microsoft excell spreadsheet that hasn't been updated since 2006, and that region doesn't even use this anymore since they scrapped it for a simmilar system a few years ago. We have been entering information in for newer cars, but it is unreliable because I don't know what the actual formula is. If there is anyone here that knows excell spreadsheets really really well, by all means, give me a shout and help me out.
I would like to propose we use a different system that works as follows:
Grip + Weight + Power = Performance
In a nutshell, vehicle grip, weight and power all combine together to give you the performance of a vehicle. So for the purpose of car equaliztion:
Your cars Grip + Your cars Weight + Your cars Power = AVG of the 3
DIVIDED BY
AVG Grip + AVG Weight + AVG Power = AVG of the 3
I'm using the following information in the calculation:
Front Tire Size, Rear Tire Size, Tire hardness (UTQG), Weight, Power
I realize that there are a lot of other pieces to the performance puzzle, but if you try to account for everything it gets VERY difficult to understand and account for. I feel like this is a very simple formula that will accomplish what it was set out to do. For example, lets look at two people from the last race:
Derek Fasano ran a 51.498 overall, and Trevor ran a 54.183. However, Jonathan has a beautiful new 911 GT3 with fat tires and 435 horsepower, which has a pretty serious performance advantage over Trevors (also beautiful) 1990 C4, that has skinnier tires and less power.
Applying the formula, Derek Fasano's PPF is 1.20, which essentially means his car is 20% faster than the average Porsche, While Trevor's is .918 or 18% slower than the average Porsche entered. By multiplying this against thier times we get:
Derek Fasano: 51.498 x 1.20 = 58.6 Adjusted handicapp time
Trevor Naidoo: 54.183 x .918 = 49.73 Adjusted handicapp time
So when you consider that Derek was in his first AX in a car that he has barely driven before AND he knocked over a cone on his fastest run (incurring a two second penalty), this looks to be a pretty good example of how the driver's actually performed considering that Trevor is the wiley AX veteran to knows how to get the most out of his car.
What does everyone think? Feedback?
- arena - 05-08-2012
Just an FYI, in my inital calculations John Bichnevicius is coming out with the best adjusted handicapp time
hock:hock:hock:
- arena - 05-08-2012
Anyone thing I should add "vehichle age" into the equation? it obviously couldn't carry much weight in the formula, but it may help equalize out some of the modern suspension technology...etc.
- RickRJF - 05-08-2012
Hello there. New member here with plenty of excel experience. I'd be happy to take a look at the spreadsheet and assist where I can.
Thanks!
Rick
- Vytenis - 05-08-2012
If handicapping cars was easy, they'd have girl/boy scouts doing it.
Previous years' RTR participants'data show less than 12% difference in PPF across the spectrum of cars, tires, modifications, etc.
SCCA PAX has approx. 7% difference from SS through HS (stock) classes, which covers everything from Corvettes to Ford Fiestas. SCCA does not take tire grip into account in most classes.
I agree that HP, weight, grip, and possibly car age will factor into predicted performance. How this is quantified, I'm not sure. The SCCA PAX and definitely old Maverick region PPF are derived from a large data set.
"V"
- arena - 05-08-2012
RickRJF wrote:
Quote:Hello there. New member here with plenty of excel experience. I'd be happy to take a look at the spreadsheet and assist where I can.Awesome! PM me with your email address, and I'll forward you a copy.
Thanks!
Rick
- trevornaidoo - 05-08-2012
V had a good spreadsheet last year for determining our PPF. My suggestion is to look at that spreadsheet, the PAX formula and add grip, age to the formula.
fyi, I still haven't figured out how to get the most out of my car. After those spins on sunday, I think the car was getting the better of me.
- arena - 05-08-2012
Vytenis wrote:
Quote:If handicapping cars was easy, they'd have girl/boy scouts doing it.
Previous years' RTR participants'data show less than 12% difference in PPF across the spectrum of cars, tires, modifications, etc.
SCCA PAX has approx. 7% difference from SS through HS (stock) classes, which covers everything from Corvettes to Ford Fiestas. SCCA does not take tire grip into account in most classes.
I agree that HP, weight, grip, and possibly car age will factor into predicted performance. How this is quantified, I'm not sure. The SCCA PAX and definitely old Maverick region PPF are derived from a large data set.
"V"
Essentially, I have averaged all of our participants tire widths, compounds, vehichle weight and horespowers. Then for each person I calculate what % above or below the average thier car is in each of those categories.
So my car:
F tire= 6.3% larger than average
R tire= 6.3% larger than average
Compound = 19% sticker than average
Weight = 2.5% heavier than average
Power = 11% more powerful than average
So I take all that, correct for the different standard deviations, correct so that the three measurements of width and tire compound count for 1/3 of the final number and average out the rest and get my PPF = 1.033 or 3.3% faster than the average car.
Simple, right?
- RickRJF - 05-10-2012
arena wrote:
Quote:RickRJF wrote:PM SentQuote:Hello there. New member here with plenty of excel experience. I'd be happy to take a look at the spreadsheet and assist where I can.Awesome! PM me with your email address, and I'll forward you a copy.
Thanks!
Rick
- CarreraSupercharged - 05-10-2012
arena wrote:
Quote:Hi guys, it's your fearless leader here, Jon.
I've been working on the PPF formula today that we have been using for the past few seasons. It's a very complex formula that is designed to equalize the performance of all the different cars, that we got from the Maverick PCA region. The problem is, that this equation is built into a Microsoft excell spreadsheet that hasn't been updated since 2006, and that region doesn't even use this anymore since they scrapped it for a simmilar system a few years ago. We have been entering information in for newer cars, but it is unreliable because I don't know what the actual formula is. If there is anyone here that knows excell spreadsheets really really well, by all means, give me a shout and help me out.
I would like to propose we use a different system that works as follows:
Grip + Weight + Power = Performance
In a nutshell, vehicle grip, weight and power all combine together to give you the performance of a vehicle. So for the purpose of car equaliztion:
Your cars Grip + Your cars Weight + Your cars Power = AVG of the 3
DIVIDED BY
AVG Grip + AVG Weight + AVG Power = AVG of the 3
I'm using the following information in the calculation:
Front Tire Size, Rear Tire Size, Tire hardness (UTQG), Weight, Power
What does everyone think? Feedback?
So your system allote the same weight for each component : 1/3 for weight of car, 1/3 for grip of the tires, and 1/3 for power. Which in reality, for autocross, handling is the most performance enhaning mechanism. This mostly comes from suspension and tires, and a great deal of the weight of the car plays in this equation. Although much less can be attributed to the horsepower of a car when comes to autocrossing. ( A good example is Chuck and Nick's car light weight and low hp). But to dedicate the sme ratio for HP, Grip, and weight, is a mistake in my opinion.
This system disproportionatly advantage the cars that sits on the extrem range of each component.
May I ask why do we have to re-invent the wheel,....especially after the season has already started...:?