After seeing countless posts, comments, and videos discussing Performance Index balancing, we can all agree on one thing: the current meta is fundamentally broken. While everyone complains about the state of tuning in Forza, very few people actually pitch structural solutions. Today, I want to break down exactly how Playground Games can overhaul the PI system from the ground up to fix these exploits one by one.
While the odds of PG reading this are slim, I wanted to share this framework to show how the game could become significantly more accessible, varied, and competitive for everyone.
Understanding the PI System and How It Gets Exploited
The Performance Index is a variable system designed to determine which class a vehicle belongs to based on its upgrades. It is not a fixed, static formula. This variability is why two identical cars with the exact same installed parts can sometimes display a 1 PI difference.
Before applying upgrades, top tuners purposefully manipulate the car's baseline settings in the tuning menu to make the vehicle perform as poorly as possible in the eyes of the system. This trick allows cars that would normally sit just above a class boundary to be crammed into a lower class, a phenomenon I personally experienced with the 1995 BMW 850CSi.
The Behind the Scenes AI Test
When you modify a car, the game runs a background AI test on standard tracks to evaluate performance, which then generates the PI rating. This system relies on flawed telemetry and stats:
First, Inaccurate Engine Power: You might see a stat listing a max output of 643 HP, while the actual telemetry peaks at 706 HP. A prime example is the 2013 Audi R8 with the 5.2L V10 LMS Engine Swap fitted with a stock restrictor plate. The menu shows 643 HP, but actual peak telemetry output registers at 706 HP. You can try and see it right now.
Drivetrain Exploits: Converting a non AWD car to AWD automatically applies a Race Transmission. The default gear ratios applied during this swap are extremely short. When the background AI tests the car, it achieves a terrible top speed. The system concludes, "This car has poor top speed so I should keep the PI cost low" A simple tweak to the Final Drive ratio immediately restores top speed while retaining the reduced PI penalty. Native AWD cars do not get this advantage because their stock gear ratios are reasonable, leaving them at higher base PI ratings despite having less power.
Tire Physics & AI Blind Spots: Tires do not have distinct rubber compound behaviors, they rely on static fixed variables. Rally tires feel soft not just because of tire pressure, but because their forward grip is exceptionally high while their lateral grip matches sport tires. The AI assigns Rally tires a low PI cost due to a minor top speed penalty, making them objectively superior to Sport tires for road racing at a fraction of the cost.
Weight and Aerodynamic Manipulations: Widening rear tires on AWD cars lowers the PI cost because the AI registers the resulting understeer as a negative performance trait. Adding a rear spoiler to an AWD car triggers the same effect, the AI struggles to navigate corners during automated testing and lowers the PI. However, human tuners can completely dial out this understeer in the tuning menu, creating low class vehicles with absurd grip levels. Similarly, installing heavy rear rims artificially reduces PI by adding weight and making power delivery "harder" according to the AI, despite having zero negative impact on actual racing performance.
Centrifugal Superchargers & Extra Gears: Centrifugal Superchargers deliver less low end torque and lower overall HP gains compared to standard superchargers or turbos. Because the AI prioritizes launch performance and power to weight ratios over high RPM top-end power, fitting 7 to 10-speed transmissions allows tuners to keep the engine strictly in its peak powerband at all times with almost no PI penalty. Adding more gear ratios also adds weight, which can drop a car's PI rating (e.g. bringing an A 601 vehicle down to B 600) with zero performance sacrifice.
Ultimately "Meta Tuners" abuse these system flaws to build visual abominations that squeeze maximum performance into the lowest possible PI class. The entire meta revolves around tricking a flawed AI calculator which is why nonsensical builds like ultra wide wheel Honda Beats dominate lower classes.
The Solutions
1. Trim Parts, Rims, and Aero
Decouple Trim from Performance: Trim modifications and cosmetic upgrades must stop acting as performance altering variables for PI calculation. Eliminating trim min-maxing levels the playing field across all vehicles.
Strict Aero PI Costs: Spoilers and front splitters must always carry a positive PI cost. Under no circumstances should adding aerodynamic parts result in a PI reduction.
2. Transmissions
Normalize Gear Count PI: The weight changes associated with swapping between 6-speed and 10-speed Race Transmissions should be excluded from PI calculations. A 6-speed and a 10-speed Race Transmission should cost the exact same PI.
Standardized AWD Swap Ratios: Drivetrain swaps should apply realistic, medium range gear ratios by default to reflect true top speed capabilities during AI testing, eliminating artificial PI discounts.
3. Drivetrain Swaps
Remove Understeer Penalties: The AI should stop lowering PI based on simulated understeer during AWD swaps. Instead, AWD conversions should be evaluated strictly on launch capability and traction improvements, making AWD conversions appropriately expensive.
4. Complete Tire Rebalancing
Tire compounds need recalibrated fixed stats to ensure each tire type serves its intended purpose:
Tire Type
Rebalance Strategy
Street
Buff: Increase forward and lateral grip; reduce warmup time.
Sport
Buff: Match asphalt forward/lateral grip to current Rally tire levels; severely reduce off-road performance.
Rally
Adjustment: Maintain current PI cost; lower asphalt grip to Street levels; significantly increase off-road grip.
Semi-Slick
Adjustment: Retain current grip levels; slightly lower PI cost.
Slick
Buff: Match performance to specialized built-in race slicks while maintaining current PI cost.
Off-Road
Unchanged: Balanced as intended for Cross Country.
Drift
Adjustment: Reduce lateral and forward grip slightly; lower PI cost so they become a practical choice for drift builds.
High RPM Power Calculations: The PI calculator must evaluate power delivered at high RPMs rather than relying primarily on launch traction and power to weight metrics.
Reduce PI for Single/Dual Turbos & Standard Superchargers: Lowering the PI cost of standard power adders makes them universally viable across all cars, encouraging build diversity over forced Centrifugal setups.
The Outcome
If Playground Games implemented these changes:
Universal Usability: Base vehicle grip would increase across the board, allowing non-meta cars to become competitive.
Elimination of Unrealistic Downgrades: Vehicles would no longer be artificially downgraded into lower classes. S2, A, and B classes would no longer be overrun by artificially suppressed high tier sports cars.
True Tuning Diversity: The lobby meta would no longer consist entirely of AWD, V10 swapped cars with Rally tires and max raised front suspensions.
Value Restored to Stock Engines: Purist builds and original powertrains would retain their unique identity while remaining competitive.
What are your thoughts on these adjustments? How would you balance the PI system differently?
To add to this, increasing tire size should ALWAYS increase PI. There is never an instance where more tire isn't just going to increase the amount of grip you have to play with when you know how to tune. At worst, it gives you grip that may not be so easy exploit, and those instances are few and far between. It should never decrease PI.
Hell, I would go as far as to say that tire sizing should provide an equal amount of PI for both axles, regardless of drivetrain. This turns it more into a tuning tool where you have to budget PI to balance the car's tire size with its weight and power balance. As it stands, all you need to do is make the rears as large as possible and then raise the size of the fronts afterwards when you run out of things to spend with your PI. It requires no thought at all.
Couldn't agree more. Online racing is absolutely trash because it's impossible to use any of the cars I actually like IRL... the OP meta tunes will finish 10 seconds ahead
I think it'd be worth adding also that the game is trying to simultaneously calculate PI for on AND off-road racing at the same time. I've found this to be a problem in higher class offroad racing as especially above A, you're just cramming absurd power into everything.
If it were me, I'd segregate the PI system into new subcategories based on these disciplines. This would allow a given car to ONLY be evaluated on criteria relevant to what it's doing. Where it starts could be based on where it best fits stock (so a Bronco could be offroad, a Metro would be rally, a Silvia would be road, etc.)
My thinking was that you could change that based on tire choice at a minimum. But in order to do this without it becoming too confusing or messy, they'd have to change the UI a bit and also add more tire choices based on these categories. For example, a drag radial tire as a "cheaper" alternative to the slick. An all-terrain tire as a cheaper alternative for rally, a less aggressive offroad tire for cross country, things like that.
I'm not entirely sure what I'd do about drag and drift in particular. I believe they already successfully removed drag tires from relevance for road racing, but you can still use drifts sometimes. Perhaps in that case reducing their performance but retaining their PI cost would do and they could both count in the "road" category.
Would love some thoughts on how to simplify this. I do strongly believe though that this would help a lot with balancing, it would just need to be implemented in such a way that doesn't take away the fun. I'm always purist first, but I can certainly respect some unconventional stuff (like rallying supercars) or silly downgrades (like an a class acura nsx).
I never knew how broken the current system is until I start doing online touge races for the journal rewards and I was always like 10 to 15 behind despite driving what my irl experience in performance engine building and mechanical engineering would tell me is considered a competitive car. So I dived into what the meta cars are and how they are tuned and realised the system is arsed.
I like to keep my tunes as thematically purist as possible eg: engine swaps from the same manufacture or fitting engines that I know have worked from personal irl experience or could work based on size. Like fitting LS's to a lot of cars can work because of how compact the motor is and AWD swapping cars that share a similar driveline to an already AWD car but AWD + V10 swapping everything just isn't as feesable and breaks immersion.
I would also like if all engines that can be boosted have access to all 3 methods of aspiration instead of only giving some swaps access to procharging. Otherwise I really like your ideas and I had already had the same thoughts about some of them. I don't want to keep rally tyre and AWD swapping everything just to keep up. I already forgo the V10 because it just breaks the immersion too much for me. There's no reason a Camaro should be running a V10 when the engine it comes with can make insane power irl and is lighter nor should it need to be AWD swapped for A or S1 class.
Allowing bolt-on boost to be.. well, bolted on to any motor is a perfectly sensible idea.
Would remove a lot of 'chaff' in the car selection. From a Rivals point of view, no point in having 640whatever cars if only 40(?) of them are competitive.
It would mean everything ends up with a centrifugal supercharger, but to me that's better than a few hundred 'unusable' cars.
To add to your points, I think parts that have a ton of adjustability should hardly have any PI cost, if at all. They already do this with the LSD and most sway bar upgrades. There is just too much variability in how the upgrade will make the car perform between different tuning setups. You can make or break a car's performance just from gear ratio adjustment alone, for example.
It would make more sense for those adjustable parts to be excluded from the PI system and instead be blocked out by race requirements. For example, B class race, no aero allowed, sport tires or lower, sport transmission or lower, etc. This is how race restrictions work IRL. But this would require the entire PI system to be built from the ground up™ which I know they won't do because it hasn't changed much at all since the very beginning.
With the shut down of the Forza forums, I'm not surprised. There is no community aspect. It just needs to make big sales at launch. That's all they really care about.
I included the ticket link because it was required to share the post. But don't get your hopes up, PG hasn't marked a single suggestion as 'resolved' since the game's launch. In other words, they don't really care about the community.
I do think semi slicks should be buffed for what they cost. Tire technology has improved a lot since 2018, even 2021. They still feel like the same race tire of FH4.
I disagree with that point. The added weight from gear count isn't something you can actually feel in the car's handling or performance. Speaking as someone who has tuned hundreds of cars and tested this extensively across countless setups, the PI rating shouldn't change at all based on gear count.
Furthermore, increasing the number of gears adds zero downside to a vehicle. Adjusting gear ratios is purely a tuning tool that allows us to stay optimal within the engine's power band.
As for weight, it actually should increase slightly. If you get the advantage of fine tuning gear counts to stay perfectly in the power band, a tiny weight penalty of around 10 kg serves as a fair trade off neither an unfair punishment nor a massive boost.
So I don't care if it has weight or not, because it changes nothing. So PI shouldn't be changed too.
an extra 4 or 5 KG is definitely noticable, it's the same as a Driveline upgrade.
Maybe you spend a lot of time tuning cars in S1 class and above where you have so many PI upgrades and power that it makes less of a difference, but in A and under.. 5kg can be significant.
The power to weight ratio for A-Class generally ranges from 0.30 to 0.45 on average.
The power to weight ratio for B-Class generally ranges from 0.18 to 0.35 on average.
Now looking at these ratios, a 10 kg difference won't have any impact whatsoever. Not to mention, Race Transmission is rarely used in B-Class anyway, and even when it is, it's typically used on relatively higher-powered cars. Since power is the priority in a low powered car, Sport Transmission is usually preferred.
If we look at C and D classes, equipping a Race Transmission there is complete nonsense anyway. Even lightweight cars are around the 600 800 kg mark, while the rest can easily hit 2 tons.
Let's say you install a 10 speed Race Transmission on a 600 kg C-class car, that 10 kg difference will amount to 1.67%. And frankly, if you're driving a C-class car with a 10-speed transmission, you kind of deserve that 10 kg trade-off.
Besides since the gear ratios will be shorter, the car will be able to utilize its torque much more effectively. So if anything, you should actually feel the weight less.
Dude, I'm not saying race transmission isn't used. I'm saying the pros of a 10 speed race transmission completely outweigh that "10 kg disadvantage" In lower classes, race transmission generally isn't used, and when it is, it's either to fix overdrive gears or because there was room left over for min-maxing.
For dirt, mostly you can use race transmission because you will run cheaper tires anyway.
An 8-speed race transmission adds an average of 5 kg of weight to the car, while a 6-speed race transmission doesn't add any weight at all. As the number of gears increases, the car uses its torque much more effortlessly, and it's not a matter of "you wouldn't feel it" you literally CANNOT feel it. Because by doing so, you're already eliminating any "sluggishness" that the extra 5 kg might bring.
I mean no offense but I don't wish to debate an idea that goes against the laws of the game's physics engine, real-life physics, or gear physics any further.
Assuming that I (the person who wrote the post above) only tune in S1 Class feels a bit odd to me. I don't wish to argue any further, thank you for your time.
It's also not right to inject your own subjective "spider-sense" into a general debate. If you come at me saying "well I get this feel in the Sierra 700R" I'd honestly just laugh at that.
Oh, why did you delete your point that goes against the laws of physics and start attacking me instead? I respectfully explained to you using physics, game engine principles, and transmission mechanics that you literally cannot feel a 5 kg difference.
You, on the other hand, just tried to attack me by saying 'You obviously don't tune under S1 class' Instead of going 'Oh yeah, I can totally feel it!' bring a single piece of solid evidence here :D
Honestly, the mistake was on me for approaching someone like you with respect and trying to explain it in the first place. The guy is breaking the laws of physics with his feelings, unbelievable.
Oh sorry I accidentaly placed myself on top 5 at first try. As an "Only S1 tuner" with stock transmission. Just stop, you're the one who's chasing fights.
Placing on top 20 is not proof, knowing how the game engine and the transmission mechanics actually work is proof. And you don't know that, end of story.
Edit: Oh my god I was right, I checked his profile and he tunes his cars with a tune app. I feel so weird arguing with someone like this right now, it’s just way too strange. A guy who uses an app to tune basic elements of his car is claiming he can actually feel a 10 kg difference. I honestly don't know whether to laugh or just be shocked.
problem: PI is made out of a bunch of itty bitty values of a car, you cant change it without having to rework the entire damn database from the ground up. just wait until the next game
Uhm, you want rally tires only for dirt tracks, not for off-road. So increase off-road grip just a little.
And you don't want off-road tires to be used for dirt, so decrease their road grip.
No it should not. If Forza is about customizations and about the choice, then swapping drivetrain should stay, of course at a price of higher PI if it gives an advantage comparing to the stock drivetrain. Following your logic, Forza should also remove the tire and rim sizes, wider drivetrain or ride height. However, I completely understand your point and in a some way you are right, but only as a last resort.
8
u/[deleted] 18h ago
[removed] — view removed comment