About

About Slipratio

Slipratio is a browser-based automotive acceleration simulator. Pick real vehicles from a public catalog, set a race distance, and watch a physics simulation play out gear by gear, with real specs, dyno curves where we have them, and real-world conditions like temperature, altitude, and track surface folded into the model.

Who runs this

Slipratio is an independent project built and operated solo. It runs on a small Cloudflare Workers footprint plus Supabase, with no advertising, no third-party trackers beyond Cloudflare Web Analytics, and no paid tier. The simulator is free to use and intended to stay free for end users. The catalog and methodology evolve from owner and enthusiast feedback. If you spot a spec or a result that looks off, the contact form and feedback@slipratio.app both go to a real person.

The physics

Each car runs on a Rust/WebAssembly straight-line model compiled from its specs: peak power and torque, dyno curves where available, gear ratios, final drive, curb weight, weight distribution, frontal area, drag coefficient, tire compound and radius, drivetrain layout, and launch behavior. The simulation steps the car through gears under throttle, slip, and aero load while ambient temperature, altitude, and track surface adjust the available grip and air density.

Because the same model runs in your browser deterministically, two users opening the same shared race link see the same result on the same car configuration. No leaderboards or random rolls. The numbers are the numbers.

Dyno tiers

Every catalog vehicle has a labeled dyno source. Pro is a curve from a verifiable third-party run (OEM press kit, named dyno shop, or licensed partner data) attached as the active dyno. Curated means a hand-checked stock torque curve shipped with the catalog row when no Pro dyno is available. Computed means the curve is generated from peak power, peak torque, and their RPMs using a physically-motivated interpolation, useful but lower fidelity than a real dyno. Custom means a user uploaded their own dyno CSV for a private custom car. The label is always visible on the spec page and on every comparison row.

Catalog policy

The public catalog ships with stock specs sourced from manufacturer documentation and reputable enthusiast publications. Each vehicle page links the source URLs we used. Owner-uploaded dynos stay private to the uploading account unless the source category and licensing posture clearly allow promotion to a public stock curve.

Limitations

Straight-line simulation only. No corners, no aero balance beyond drag, no tire degradation across a stint. Launches assume a flat surface and the configured surface friction. Results are best read as relative comparisons (this car versus that car under these conditions), not as official certified times.

Next steps

Open the simulator to run a race, or browse the full vehicle catalog. Feedback, missing cars, and bad-sim reports are all welcome.