Tech Articles

Structured technical content across engine fundamentals, EFI hardware, and calibration principles.

A black and white THIS WAY sign with upward arrows above a staircase, marking where to start with EFI tuning
Two VE curves for a higher-lift and lower-lift cam of the same duration, showing the higher-lift cam holding volumetric efficiency up at high RPM

Camshaft profiles and valve timing: how they shape your VE curve

Cam specs tell you more than which RPM range an engine likes. They predict the shape of the VE table you'll be tuning, and why a cam change means starting that table over.

Four-cylinder engine cutaway showing pistons, connecting rods, and crankshaft

Compression ratio: what it tells you about power, efficiency, and knock

Static compression ratio is the first number you check on an engine. What it tells you about efficiency and knock, what it leaves out, and why it still matters.

An external crank trigger wheel and position sensor mounted on the front of an engine

Trigger patterns explained: why your ECU needs crank and cam signals

Before your ECU can open an injector or fire a coil, it has to know engine position and engine speed. The crank and cam signals provide this information to the ECU, and a fault in them is a common reason an engine cranks but won't start.

Lambda and injector duty cycle plotted against engine speed approaching the fuel system limit

You're at the injector duty cycle limit: how to decide what to do next

Your injectors are maxed out and the mixture is wandering at the top of a pull. Confirm the limit is real before you act, then weigh each fix and what it costs.

A row of fuel pump nozzles labelled with different fuel grades, including 92 and 95 octane

Octane ratings on ethanol blends: what the number actually tells you

Two fuels with the same octane number can knock differently in the same engine. What RON and MON actually measure, why sensitivity matters, and why ethanol blends beat their rating.

Gasoline E0 and E85 fuel property cards compared side by side

How E85 changes your calibration

E85 needs more fuel, cools the charge, resists knock, and shifts your ignition timing in both directions. The physics behind each calibration decision.

Effective injector flow versus boost pressure for a fixed-pressure regulator versus a 1 to 1 manifold-referenced regulator

Injector Sizing: The Reasoning Behind the Numbers

Injector sizing rests on one number nobody can confidently pick. What BSFC actually is, how to size without guessing it, and why the duty cycle margins exist.

Lambda target zones across the engine operating map, showing idle, cruise, moderate load, full load, boost transition, boost, and decel zones with their primary objectives

What AFR should I run? Choosing the right lambda for the conditions

Lambda targets aren't a single number copied across the map. Why each zone wants something different, where to start, and the constraints that set the limits.

V8 cylinder block with bores visible from above, foreground and background, with warm light catching the deck face

Why bore diameter determines knock frequency

Knock frequency is set by bore diameter. The formula, the resonant modes, why Mode 0 is the default and Mode 2 is the strongest fallback, and how to use the calculated value in practice.

Block diagram of airflow-based ECU fuel calculation showing inputs, airflow estimation, air mass, fuel model parameters, and pulse width output

How ECUs calculate fuel delivery

The VE table isn't always storing what you think it is. Where airflow estimation ends, where the fuel model begins, and why errors in one end up in the other.

Plex combustion analysis software showing in-cylinder pressure traces and knock intensity data

Why knock appears under some conditions and not others

Knock threshold isn't a fixed number. It moves with ignition timing, boost, intake air temperature, coolant temperature, fuel octane, AFR, and engine speed simultaneously.

2D ignition timing map showing timing values across RPM and load

How ignition timing produces torque and what limits spark advance

The physics behind ignition timing decisions, what MBT means in terms of cylinder pressure, and where knock sets the ceiling.

A typical naturally aspirated VE table surface

What your VE table shape tells you about your engine

VE tables aren't just fuelling maps. The shape tells you how the engine breathes, where it's most efficient, and where something might be limiting performance.