Forza Horizon 6 Isn’t Showing You Your Real Horsepower — Meet the Hidden Torque Multiplier

A weird two-numbers-for-one-stat quirk in Forza Horizon 6 means the horsepower figure on your car’s spec sheet is, for a lot of cars, flat-out wrong. Here’s how to calculate what your engine is actually making — full credit to Johnson Racing (@Johnson_Racing) and LetzeLU (@LetzeLU), who did the testing and the math.

Build two muscle cars to the same spec — same engine swap, same tune, same 455 horsepower on the card, near-identical weight — line them up on a drag strip, and they should cross the line together. In Johnson Racing’s latest video, they didn’t. One Dodge walked away from the other by a full 3 seconds. Same displayed power. Same weight. One is in B-class, the other in A-class.

That’s not a driver-skill story, and it’s not a bug in the build. It’s a number Forza Horizon 6 keeps off your spec sheet on purpose — a fixed, per-car torque multiplier — and once you know how to read it, the whole PI system suddenly makes a lot more sense.

What the game shows you isn’t what the car makes

Open any car’s stats and you get a horsepower figure. You reasonably assume that’s the power the game actually simulates. For a huge chunk of the car list, it isn’t. Every car carries an invisible torque multiplier — a hidden coefficient the developers set per car — that scales your displayed horsepower up or down into the number the physics engine really uses. Some cars get buffed. Some get quietly gutted. The card never tells you which.

The tell that this exists at all is a discrepancy hiding in plain sight: Forza shows your power-to-weight ratio in two different menus, and the two values don’t match. That mismatch isn’t a rounding glitch — it’s the multiplier leaking through. Community tuners have flagged that Forza has carried some form of this since FH5 (treat that as community knowledge, not an official spec), but the game has never surfaced it directly. It just shows you the answer twice and lets you notice the gap.

The proof: two “identical” Dodges, one 3 seconds up the road

Johnson Racing and LetzeLU built matching classic muscle — a 1969 Charger R/T and a 1968 Dodge Dart — same swap, same tune, both reading 455 hp at roughly 1,266–1,267 kg. On paper, a coin-flip. In the drag race, the Dart cleared off by about 3 seconds.

The scoreboard already knew why. The Dart lands in A-class at 637 PI; the Charger sits in B-class at 573 PI — off, the video argues, the exact same build. Here’s the part people get wrong when they see a result like that: they blame the tune, or the driver, or launch. The real variable is that the PI system is reading each car’s true output, multiplier included, while the horsepower number on the card is not.

How to find your car’s torque multiplier

The multiplier isn’t printed anywhere, but the game hands you enough to back it out in about thirty seconds. It comes from those two mismatched power-to-weight readings:

Grab the “real” power-to-weight. In Upgrades & Tuning, open your tuning setup — the power-to-weight ratio shown here is the accurate one. On the Dart, that’s 0.41 hp/kg.
Grab the “displayed” power-to-weight. Go to the Custom Upgrade menu and read the power-to-weight there, on the same setup. On the Dart, that’s 0.36 hp/kg. (Same setup in both menus, or the math won’t hold.)
Divide the first by the second. Tuning-setup value ÷ Custom-Upgrade value. For the Dart: 0.41 ÷ 0.36 = 1.138. That’s your torque multiplier.

A multiplier above 1.0 means the car makes more than the card claims. Below 1.0 means the game is skimming power off the top.

Turning the multiplier into real horsepower

Multiply the displayed horsepower by the multiplier and you get what the car is actually putting down:

Car	Displayed hp	Torque multiplier	Real hp	Class / PI
1968 Dodge Dart	455	1.138	~518	A / 637
1969 Charger R/T	455	0.694	~316	B / 573

The Dart’s “455” is really about 518 hp. The Charger’s identical-looking “455” is really about 316. Two cars the spec sheet swears are twins are, in the simulation, roughly 200 horsepower apart — which is exactly the kind of gap that turns a drag race into a 3-second blowout. Divide the Dart’s ~518 real hp back by its weight and you land on 0.41 hp/kg again, confirming which menu was telling the truth: the tuning-setup number is real, the Custom-Upgrade number is built on the fake horsepower figure.

The honest caveats — because a multiplier under 1.0 isn’t a death sentence

Two things worth keeping straight before you go re-rating your whole garage.

First, the method’s precision is limited by the game itself. Forza only shows those power-to-weight values to two decimals (0.41, 0.36), so dividing them carries a real margin of error — the multiplier you get is a close estimate, not a lab result. Tuner dust008 (the same creator behind the turbo-lag meta we covered) posted a tighter method in the comments: nudge upgrades until the “real” power-to-weight ticks over by 0.01, use the weight at that threshold, and solve for the exact figure. By that math the Dart’s multiplier lands at 1.13 and the Charger’s near 0.70 — squarely in line with the video’s numbers. A couple of viewers also, fairly, wanted both cars re-tuned to the same true horsepower and raced again to fully isolate the variable; the drag result plus the class gap is strong evidence, but that’s the cleaner experiment.

Second — and this is the part that matters when you’re picking a car — a multiplier below 1.0 does not mean the car is bad. The 2008 Viper carries a multiplier around 0.9 and is still one of the strongest A-class and S1 cars in the game. Torque is only one of several hidden figures; drag coefficient and downforce are in there too, doing their own quiet work, which is why a “nerfed” car can still corner and accelerate like a monster. The multiplier explains the horsepower mystery. It doesn’t explain the whole car.

The Bottom Line

Forza Horizon 6’s horsepower stat is a headline number, not the truth. The truth is displayed-hp × a hidden torque multiplier, and you can pull that multiplier yourself by dividing the tuning-setup power-to-weight by the Custom-Upgrade one. When two similar builds behave nothing alike, this is usually why — and it’s also why PI, for all the grief it gets, is quietly the most honest number on the screen: it already bakes the multiplier in.

Want to know which of your favorites are secretly buffed? Pull up any two cars, run the two-menu math, and check the gap. You might be sitting on a sleeper — or driving a card that’s been lying to you all along.

Full credit to Johnson Racing and LetzeLU for the testing and the method — watch the original video, Forza Horizon 6 LIES TO YOU About Car Performance!. Refined-calculation method and the classic-muscle multiplier table courtesy of dust008 in the video’s comments. Analysis and write-up by ApexSpeedCraft.