Engine Simulator – BMEP Toy Dyno v4

Build an engine concept and this tool estimates torque, power, BMEP, airflow, and fuel use across the RPM band using a BMEP → torque → horsepower model. Educational use only – not a real tuning tool.

Engine Setup

Loads a baseline close to real engines, then you can tweak.
Mode controls fuel type, BMEP range, and knock / boost limits. Other options refine it.

Geometry & RPM

1–12, e.g. 4, 6, 8.
Bore diameter.
Stroke length.
Calculated from bore, stroke & cylinders.
Gas NA: ~9–11 · Gas turbo: ~9–10 · Diesel: ~16–18 · Methanol: ~12–15.
Max simulated RPM.
Resolution of the curve.

Breathing & Limits

Best-case VE around peak torque.
hp/L penalty as displacement grows above 2.0 L.
Above this, torque drops from stress/friction.

Induction & Valvetrain

Used for turbo/supercharged modes. Gas NA ignores this. Diesel & methanol use it when turbo.
Only used when mode = Methanol Race. Ignored otherwise.
Impacts NA & boosted gasoline curve shape. Diesels mostly ignore this.
More valves = better high-RPM breathing in gas engines.

Results

Peak Power

– hp @ – rpm

Peak Torque

– lb-ft @ – rpm

hp per Liter

– hp/L

Fuel @ Peak Power

– lb/hr (– gal/hr)

BMEP @ Peak Torque

– psi

Airflow @ Peak Power

– CFM

RPM HP Torque (lb-ft) VE (%) Piston Speed (m/s) BMEP (psi) Airflow (CFM) Fuel (lb/hr) Fuel (gal/hr)