Nasty Fast Parts · Two-Stroke Tech Tools
Engine Build Simulator v84
Estimate horsepower, torque and BMEP using the same saved machine, Jetting and measured compression data as the other NFP calculators.
Shared Builds · Jetting / Gearing / Premix / Engine Tools
Shared named builds are stored in this browser on this site. JSON files move them between devices.
Engine Build
Estimate how a two-stroke build's displacement, porting, pipe, carburetor and RPM range can influence its power curve.
Copies source settings into this simulator. Click Save to keep them.
Machine & Cylinder
Porting, Pipe & Intake
Compression & Environment
If chamber volume is entered, calculated from bore / stroke / volume. Never infer from gauge PSI.
If known, geometric compression is calculated from chamber volume.
Gauge reading is shown for reference, not converted directly into a ratio.
Pipe profile influences preferred peak-power RPM.
Shown for build documentation. Not a measured airflow multiplier.
Estimated Performance
Compression values are estimates unless chamber volume and squish clearance were measured.
Estimated Flywheel HP & Torque
Simulation uses explicitly assumed BMEP/powerband coefficients, not dyno calibration. It does not predict detonation, thermal failure, exhaust wave tuning, transmission losses, gear acceleration, or whether the physical porting supports this RPM. Never use these horsepower predictions alone to choose jetting or ignition timing.