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The method: stock to finalYour first session, step by stepTroubleshooting
Engine & fuel
VE and speed-density fuellingLambda, AFR and target mixturesInjector scaling and dead timeFuel system capacityE85 and the stoich setting
Spark & knock
Ignition timing and MBTKnock, knock sensors and false knock
Boost, heat & limits
Boost control and wastegatesHeat: IAT, EGT, coolant and protectionMechanical limits
Reading results
Reading a dyno sheet and logCorrection factors and fair comparisons
Reference
Same concept, different namesWhat real software has that this does not (yet)
Engine & fuel

Fuel system capacity

Pump, regulator and injectors together set how much fuel you can actually deliver. Boost and E85 eat capacity fast.

The regulator holds the rail a fixed pressure above the manifold (here 300 kPa). Under boost the rail pressure rises one-for-one with MAP so the injectors keep the same differential pressure — which is why injector flow is rated "at 300 kPa".

The pump has a finite flow that falls as pressure rises. When the injectors demand more than the pump can supply, rail pressure sags, each millisecond of pulse delivers less fuel, and the engine goes lean while the ECU thinks it is doing fine. In the log: fuel pressure drops below (300 + boost) as λ climbs.

  • Bigger injectors do not fix a pump that cannot feed them.
  • E85 needs ~40 % more fuel flow for the same λ; stock injectors on a turbo car usually go static.
  • A large turbo with the stock pump will sag pressure at the top end before anything else complains.
Now try it.

Set the injector data, stoich and limits on a virtual car, then pull it and see what the numbers do. Free, in the browser, no account.

Open the Scalars tab in the dyno →