How it works, and what to do about it.
Each guide starts with what a part does and whether you need it, then how to choose and fit one, then the numbers and trade-offs. Read as far as you want to go.
Planning a build
- What Order to Mod Your Car In
Why maintenance, tires, brakes and suspension usually come before power, why power adders need supporting mods first, and how to plan a buy order.
18 min read
Tuning
- What Does an ECU Tune Do?
An ECU tune changes the fuel, timing, boost and limiter tables an engine runs on. What changes, how it is delivered, and how tuners verify it worked.
17 min read - Stage 1, 2 and 3 Tunes Explained
Stage 1, 2 and 3 are informal shorthand for how much hardware a tune assumes, not a standard. What each stage usually means and how to verify one.
17 min read - WHP vs Crank HP: Reading Dyno Numbers
Wheel horsepower and crank horsepower are not the same number, and dyno results are not comparable across dyno types. How to read a dyno sheet correctly.
17 min read - Datalogging: What to Log and Why
A datalog is a recording of what the engine was actually doing under a tune. What channels to log, how to read a pull, and the signs of trouble to look for.
16 min read - How to Read a Dyno Graph
A dyno graph plots power and torque against rpm. This guide covers the axes, before/after overlays, and spotting a dip, an early fall-off or boost creep.
21 min read - How to Read Datalog Graphs: AFR, Boost and Fuel
How to read a datalog graph: lining up AFR, boost and fuel pressure through a pull, and what a lean spike usually means.
22 min read - Reading Ignition Timing and Knock Logs
How ignition timing and knock retard read in a datalog, why timing drops under boost, and how to tell real knock from sensor or mechanical noise.
18 min read
Fuel
- How to Size Fuel Injectors
What injector flow ratings mean, the formula for sizing a set, and why duty cycle, fuel pressure and dead time all matter.
18 min read - Fuel Pump Upgrades: When and What Size
How in-tank lift pumps are rated, why free-flow numbers mislead, and the symptoms that show a pump is running out.
17 min read - E85 and Flex Fuel Explained
What E85 is, why it resists knock better than gasoline, what it needs from the fuel system, and why it needs its own tune.
17 min read
Power and breathing
- Turbo vs Supercharger: How They Differ
How turbochargers and superchargers force air into an engine differently, what each trades off, and what both need to support around them.
17 min read - Intercoolers Explained
Why compressed air gets hot, how air-to-air and air-to-water intercoolers cool it, the physics behind the heat rise, and how to judge one with IAT logs.
17 min read - Intake and Exhaust Upgrades: What They Do
What cold air intakes, axle-back, cat-back, headers and downpipes change, why the catalytic converter is not optional, and why bolt-ons often need a tune.
17 min read
Engine and cooling
- Forged Internals: When an Engine Needs Them
Cast, hypereutectic and forged pistons compared, what fails first under boost, I-beam vs H-beam rods, and when a build actually needs forged internals.
21 min read - Oil and Engine Cooling for Modified Cars
What oil viscosity numbers mean, why oil and coolant temperature matter under load, oil coolers, baffled pans, and what overheating looks like in a log.
19 min read - Camshafts and Naturally Aspirated Power
Lift, duration and lobe separation angle explained, what a cam moves in the power curve, valve springs, idle quality, and why a cam change needs a tune.
19 min read
Drivetrain
- Clutch Upgrades and Torque Capacity
How clutch torque capacity relates to clamp load, friction material and effective radius, and the drivability trade-offs of a stronger clutch.
17 min read - Limited-Slip Differentials Explained
Open vs clutch-type, helical and electronic limited-slip differentials compared, what preload and ramp angle do, and how an LSD changes handling.
19 min read
Suspension and chassis
- Lowering Springs vs Coilovers
Lowering springs versus coilovers explained: what each changes about ride height, spring rate and damping, and what going lower costs elsewhere on the car.
17 min read - Wheel Alignment: Camber, Caster and Toe
Camber, caster and toe explained in plain terms, how street and track specs differ, what lowering does to them, thrust angle, and reading a printout.
20 min read - Weight Reduction: What It Gains and Costs
How power-to-weight arithmetic works, why unsprung and rotating mass count more than static weight, and what removing weight actually costs in comfort and safety.
17 min read - Lift Kits and Bigger Tires for Trucks
Leveling, spacer and suspension lifts compared, tire diameter arithmetic, the speedometer error a bigger tire causes, regearing, and load and height-law effects.
18 min read
Wheels and tires
- Wheel Offset, Width and Fitment
How offset, width and backspacing move a wheel in the fender, what poke and tuck mean, and the checks that keep a new wheel and tire combo rubbing-free.
17 min read - Tire Compounds, Treadwear and UTQG Ratings
What UTQG treadwear, traction and temperature grades mean and their limits, compound types from touring to R-comp, heat cycles, size codes, load index and pressure.
19 min read
Brakes
- Brake Upgrades: Pads, Fluid, Rotors, Kits
What pads, fluid, rotors and big brake kits actually change, why tire grip limits stopping distance, and what to check before fitting bigger calipers.
19 min read
Track and drag
- How to Prepare for a Dyno Day
What to check on the car before a dyno session, fuel and fluids, tire pressure and strapping, what to ask the operator, and how to read the sheet you take home.
19 min read - Your First Track Day: Car and Driver Prep
What an HPDE day is, tech inspection items, brake and tire prep, run groups and flags, what to bring, and the etiquette that keeps a first track day safe.
19 min read - Launch Control and Drag Racing Setup
How launch control and two-step work, tire pressure and drivetrain shock at launch, reading 60-foot times, and the rough relationship between trap speed and ET.
20 min read
Legal and emissions
- Emissions-Legal Mods and CARB EO Numbers
What CARB Executive Orders are, how they work in general, which parts typically need one, and why the rules vary by state and change over time.
18 min read - Lighting and Window Tint Laws for Modified Cars
How window tint and lighting laws generally work: VLT percentages, which windows they cover, medical exemptions, headlight color, and underglow rules.
19 min read