Opel C20LET
The C20LET is the turbocharged sibling of the Red Top, used in the Calibra and Vectra Turbo, and the preset carries the lower 8.5:1 compression ratio that forced induction requires. Putting the two presets next to each other is the clearest illustration in the whole library of what turbocharging actually trades: the C20LET gives up part-throttle efficiency and peak-pressure margin in exchange for far more air. Because the block geometry is identical, every difference you see in the P-V diagram comes from compression and intake pressure alone. The calculator returns the full cycle plus the gas and inertial loads on the rod and crankshaft.
Preset parameters
Values below are the preset the calculator loads — you can change every one of them in the form. Angles are absolute crank angle (CA) on a 0–720° cycle.
Reference figures
Manufacturer figures carried by the preset for comparison. They are reference values, not calculator output.
Notes for modelling
- Raise intake pressure (pik) in steps and watch peak cylinder pressure — that curve is the practical boost limit of the stock bottom end.
- Ignition timing and burn duration are editable; retarding ignition is how real boosted engines buy knock margin, and the model shows the power it costs.
- Carry peak pressure into the stress calculator for a rod and stud check.