Question About Determining Performance Index

[OrdainedBasher]

This has been on my mind lately, more so now seeing the threads debating the new Ford GT LM’s performance index.

I seem to recall reading that Forza uses a test track to determine the PI value of the cars. This was months ago and I can’t find the link now, unfortunately.

Does anyone know if that is the case? If so, has anyone ever seen the layout of this track? If I’m totally wrong, does anyone know all the details of how it is determined?

[IceMan_PJN]

I don’t think it’s nearly as simple as that. PI can’t just be a factor of what they got from a test track because a car’s performance and PI aren’t a fixed value. There’s a heap of possible upgrade combinations that will affect performance and consequently PI. If a given car has a total of 60 different available upgrades, not even counting the different rims, and those can largely be mixed and matched in thousands of possible combinations, I doubt someone ran thousands of test track runs just on that one car to come up with PI ratings for thousands of potential upgrade combinations. Then do that with each of the several-hundred other cars.

[ManteoMax]

FAQ thread pinned at the top of the forum:

@ManteoMax

FM6 FAQ: Cars

How is a car’s Performance Index (PI) calculated? How realistic are the driving characteristics?

@JONK1969

Forza uses a classification and “Performance Index” scoring system to fairly balance cars across the game. This PI system refers to a ranking number based on a car’s best lap time around a simulated test track. The slower the lap time, the lower the PI number; the faster the lap time the higher the PI. This test track is mathematically generated to be representative of the all race tracks in a specific game. We call this a “PI test track.”

PI ranking, however, is different for each game. It is relative to each game’s car list and race routes. Each new Forza title gets another revision of this test track to be a good representational average of all tracks in the game. This, in addition to the changing and growing car list with each title, is why class boundaries and PI #s are not the same with each new version of the game, or between Motorsport and Horizon.

Forza Motorsport titles use an entirely different PI test track than Forza Horizon titles, because race tracks (like Silverstone, for example) are not representative of the types of race routes found in Forza Horizon’s open roads. Horizon’s roads tend to have longer straights, faster turns, and less hard braking and cornering in general. For this reason, the actual class letters and PI values for a given car are not the same between Horizon and Motorsport games. Additionally, Forza Motorsport has Formula 1, Indy, and modern prototype race cars at the top of its PI system, while Horizon 2’s top-end cars are “hypercars” like the McLaren P1 and LaFerrari. This means a PI of 998 in Forza Motorsport is a much higher level of performance than a PI of 998 in Forza Horizon. It also means less granularity is needed in Horizon’s car classes than we have in Motorsport. Again, it’s relative to each game’s cars and race routes.

Once we have PI test track lap time data for every car in the game, we analyze it to determine class boundaries. Most of these land exactly where we would expect, based on the fact that all the performance data for each car is based on extensive real world research, including data provided to us directly by car, tire, and aftermarket parts manufacturers as well as race teams.

We rarely hand tune PI, and if so it is to maintain fair game balance across career, multiplayer, and leaderboards, or to keep cars of similar type and performance in the real world in similar PI ranges or classes, and never to a degree that a car’s performance characteristics are significantly compromised compared to its real world counterpart.

Lastly, of course we allow players to upgrade and tune their cars to be competitive with cars that have a much higher PI in stock form, within the bounds of real-world limits. In multiplayer or rivals competition, it’s not uncommon to see cars which, in stock form, would have no chance of winning, but with a great tune (and driver!) can smoke the competition.

[OrdainedBasher]

I think I might’ve over simplified the question. This post is what I was referring to though! Thank you!

[OrdainedBasher]

This now leads to my second question, which I may not be able to fully articulate as I’m typing this on a phone at work. Let me try though.

Is this theoretical track a representation of the various features of each track or more so all the circuits sort of strung together, thus making a comprehensive, if exhausting, test?

Using the previous GT Le Mans thread, where the discussion is comparing the lap times of the Ford to those of the 458 from last year’s WEC race at Spa.

The Ford was slower than the Ferrari. There are a multitude of variables that can completely overrule the assigned values of the GT Le Mans and 458 GTE, including traffic, race conditions, tire compound etc. Additionally, Spa has only a fraction of the different layout and geography found across all tracks.

However, could we now say the Ford’s value is higher as it has a faster theoretical time around this test track, though the Ferrari may be faster around a more nuanced circuit?

[ManteoMax]

I think the answer is given in the quote. “This test track is mathematically generated to be representative of the all race tracks in a specific game.”

[OrdainedBasher]

I suppose you’re right. Thanks very much for the reference and the help!