Tuning Guides
The maths behind the mods, in plain English. Each guide explains one topic properly — then hands you the free calculator to run your own numbers. No fluff, no sign-up.
// Guides
How to read a tire size
What every number on your tire sidewall means — width, aspect ratio, construction, wheel diameter, load index and speed rating — with worked examples.
6 minWheel offset explained
What ET / offset and backspacing mean, how positive vs negative offset changes where a wheel sits, and how to work out whether a wheel will clear or poke.
6 minCompression ratio explained
What static compression ratio means, how it's calculated from bore, stroke, chamber and gasket, and what ratio suits NA versus boosted engines.
6 minAFR and lambda explained
What air-fuel ratio and lambda mean, why stoichiometric differs by fuel, and the AFR targets tuners use for cruise, NA and boosted wide-open throttle.
5 minPower-to-weight ratio explained
Why power-to-weight predicts performance better than horsepower alone, how to calculate it in hp/ton and kg/hp, and how to compare cars fairly.
7 minHow to size a turbo
How to pick a turbocharger from a power target: required airflow in lb/min, pressure ratio, and how to read a compressor map without getting lost.
6 minBrake bias explained
What front-to-rear brake bias is, how weight transfer under braking sets the ideal split, and what happens when the balance is wrong.
6 minCorner balancing explained
What corner weights and cross-weight (wedge) mean, why 50% cross makes a car handle the same both ways, and how corner balancing actually works.
6 minTrap speed vs ET explained
What quarter-mile ET and trap speed each measure, why trap speed is the honest power number, and how to read a drag strip time slip like a racer.
6 minInjector sizing explained
How to size fuel injectors from a horsepower target: BSFC, duty cycle, cc/min vs lb/hr, and why oversized injectors hurt idle quality.
6 minDyno correction & density altitude explained
Why the same car makes different power on different days, how SAE J1349 correction factors work, and what density altitude tells you about NA power loss.
6 minE85 explained
What E85 is, why it makes more power and needs ~30% more fuel, what a flex-fuel conversion actually involves, and how to blend to a target ethanol content.
6 minGear ratios explained
What gear ratios and final-drive numbers really mean, how they trade acceleration against cruise rpm, and why tire diameter is part of your gearing.
6 minCamber, toe & caster explained
The three alignment angles: what each one does, how each wears tires, and ballpark specs for street and track — plus the mm-to-degrees maths.
6 minCamshaft specs explained
How to read a cam card — duration, lift, LSA and overlap, what each does to the powerband and idle, and why overlap is a cam's personality number.
5 minHow to read OBD-II codes
What every character of an OBD-II trouble code means — system, generic vs manufacturer-specific, family and fault index — and how to turn one into a diagnosis.
5 minBolt pattern (PCD) explained
What a bolt pattern like 5×114.3 means, how to measure yours with a ruler, the mm ↔ inch conversions, and why PCD is only part of wheel fitment.