Turn your red
deltas purple.

No. Purple Delta is an unofficial companion app for Gran Turismo 7. It is not made by, endorsed by, or affiliated with Sony Interactive Entertainment or Polyphony Digital. Car and circuit names are used only to identify in-game content.

You pick a car and a track, type your car's power, weight and Performance Points (PP) from its GT7 page, and choose the tyre, the weather, a driving style and the parts you've fitted. The engine works from the car's own GT7 figures and the track's character (how bumpy, how technical, how long the straights) and returns a full sheet in seconds, on your phone: body height, natural frequency, anti-roll bars, damping ratios, camber, toe, LSD, downforce, transmission top speed and brake balance, plus the power restrictor, ECU output and ballast where your figures need them. You type the values into GT7 yourself.

Tuning does. Setups are generated on your phone, so they need no connection. Signing in, the Community Garage and subscriptions need one.

583 cars from 77 makers and 122 track layouts at 41 venues — every car and track in GT7 1.71, including the cars 1.71 added. Every car is tunable with Pro; the free plan covers the GR Supra Race Car '19, plus one featured car per Daily Race, free that week. Wet setups are offered wherever GT7 runs rain, and dirt tracks get dirt tyres.

No. They haven't been lap-tested, and no setup app can promise a win. Each sheet is a physics-based starting point for your car's power, weight and PP: it saves the blank-page guesswork, and you fine-tune it at the wheel to your own driving. Rate any tune Helpful or Not quite in the app and it goes straight to the developer.

Free lets you fully tune the GR Supra Race Car '19, plus one featured car per Daily Race, free that week; browse every car and track; use the Tune Troubleshooter on the cars you can tune; and read, publish, like and comment in the Community Garage. Pro unlocks full tuning for every car in GT7 1.71 and saves your tunes to a garage that syncs to your account on every device. Pro is £1.99/month or £14.99/year in the UK (save 37%), with local prices at checkout. The annual plan has a 7-day free trial for eligible new subscribers.

Yes, on the annual plan: 7 days free for eligible new subscribers, then £14.99/year in the UK (local prices at checkout). It's offered on both the App Store and Google Play, and the app shows it only if your store account is eligible. Cancel in your App Store or Google Play account at least 24 hours before the trial ends and you won't be charged.

Yes, once the car is built. Get it under your lobby's PP cap in GT7, then type its power, weight and PP into Purple Delta: the sheet is built for exactly those figures, and if you cut power or add weight it fits the power restrictor or ballast that change needs. It doesn't tell you which settings a BOP race locks, so check the race's regulations for what you can change.

Yes — that's the Tune Troubleshooter. Tick what the car does wrong from 24 handling problems in six groups (understeer, oversteer, traction, stability, speed and tyres), such as "Pushes wide on turn-in" or "Rear steps out on entry (lift-off)", and Update Settings applies the suspension, differential, brake and downforce changes to your sheet. It takes your drivetrain into account, and if a change needs a part you haven't fitted, it skips it and names the part to fit. Treat it as the next thing to try at the wheel.

Yes. Purple Delta produces in-game tuning values you enter in Gran Turismo 7, so the setups apply the same whether you play on a wheel or a controller.

Gran Turismo 7 on PS5 or PS4, and the Purple Delta app on an iPhone, iPad, or Android phone or tablet. You read the values in the app and enter them on the car's settings screen in GT7. The app is free, with an optional Pro subscription (£1.99/month or £14.99/year in the UK; the annual plan has a 7-day free trial for eligible new subscribers).